Re: [Emc-users] Carving a spiral

[Dave Engvall]

https://www.britannica.com/science/spiral-mathematics
Several options here, take your pick. 
Should be trivial to move it from floating pt to fixed. 
May have to scale to make it happy. ;-)

Dave


> On Apr 10, 2024, at 12:09 AM, gene heskett  wrote:
> 
> On 4/10/24 01:57, John Dammeyer wrote:
>> A friend and I have been discussing exactly how to write the G-Code to
>> create a spiral scroll.
>> His rotary table 90:1 reduction with a 1600 micro-step motor could be set up
>> to move N steps for each step of the X axis to create the spiral.  But that
>> approach seems clumsy.
>> Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter.
>>  Without using G2 or G3 it's really just a triangle isn't it?  Move rotary
>> table distance A and move X axis distance A'.  Do it in small enough
>> increments and you get a spiral.  But I feel like I'm missing something
>> really simple.
> First, a 90/1 is quite high. I have two rotary's, both consisting of a 3NM 
> 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. Using 
> a screw in the worms output hub as a single prox sensor index pulse 
> generator. To calibrate a complete rev, I measure the steps by starting the 
> count on the 3rd turn ans stopping the count on the 103rd turn, which gives 
> me a scale*100.  Shift the decimal point 2 places left this becomes the scale 
> for the axis in the .ini file.  All this math in linuxcnc is floating point 
> so I can ask it for 33.333 degrees and it will run to what it thinks is 
> 33.333 degrees. This stepscale:
> STEPSCALE   = 22.222 = 1 degree
> So one count is about 1/22.222 degrees, probably less than the 
> backlash in the rvs39 worm, a pretty cheap worm.
> 
> Currently to make one of my maple vise screws, starting at 0 degrees its 
> around 60,000 degrees it turns for around 400 mm of screw that y travels. 
> Then I lift the tool, turn it another 180 degrees, re lower the tool and 
> bring y back to zero and b=180. Makes a perfect two start buttress thread. 
> The B is turning, in perfect sync with the Y motion, at something in the 300 
> to 400 rpm range. That 3NM motor is heating but not dangerously so.
> 
> There is no reason you couldn't lay it down to make a C drive, and 
> simultaneously drive X Z & C to carve an impeller in a quite serviceable 
> scroll.
> 
> The versatility of the closed loop stepper/servo, which does EXACTLY what the 
> TP tells it to do, without a PID in the path, is amazing. I have them rigged 
> to e-stop linuxcnc in about a millisecond if they make an error, like losing 
> a step. Tested till the cows come home, has yet to happen working a job. I 
> haven't hobbed any gears, but it certainly seems accurate enough to do it.
> 
>> Suggestions?
>> Thanks
>> John
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> 
> Cheers, Gene Heskett, CET.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> 
> 
> 
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Re: [Emc-users] Not so slight problem with spindle/tools

[Dave Engvall]

I have a very good Cat40 bolt to bench for installing tools but it is a nasty 
job to bolt the cat40 back into the spindle. 

If I could get access I’d pull the whole mess and replace (ideally). The stack 
is 105 washers so not too expensive. I’ll climb up on top and take another good 
look down the bore and see if there is any hope. 


> On Mar 19, 2024, at 1:12 PM, BRIAN GLACKIN  wrote:
> 
> The mining industry uses these washer stacks to secure replaceable wear
> plates in Jaw crushers.  Twist the nut down until the compressed washers
> all fit into a “cup” and viola bolt is torqued and the bolt has additional
> springiness beyond just the steel of the bolt
> 
> I would agree with Todd replacement is best as these are technically “wear
> parts”. But sounds like the ability to do this job was redesigned to be
> costly and less repairable.
> 
> Can you add an extension the rod and add an additional stack of washers in
> a more convenient location?   Got a cross section of the area?
> 
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Re: [Emc-users] black list aliexpress

[Dave Engvall]

Considering how much of the Ru munitions have western chips proves how much of 
the world is willing to cheat for a buck. 

> On Mar 18, 2024, at 7:33 PM, gene heskett  wrote:
> 
> On 3/18/24 18:50, Jon Elson wrote:
>> On 3/18/24 07:53, Todd Zuercher via Emc-users wrote:
>>> Gene,
>>> 
>>> In all honesty I wouldn't mind knowing more about your VFD source you say 
>>> you want black listed.  I'm so sick of trying to track down high speed VFDs 
>>> that I'm almost tempted to pay the machine manufacturer's ridiculous 3X 
>>> normal retail list price markup the next time we need a new one.   We 
>>> occasionally have needed a replacement VFD capable of running about a 15kw 
>>> 4pole router spindle at up to 24krpm (that is 800hz output, most drives 
>>> seem to max out at or are limited to 500-600hz output.)  The last time we 
>>> tried to order a new drive with these specs it was put on back order for 
>>> more than 1 year before we canceled the order.  (We canceled after the 
>>> delivery date had been pushed back 3 months for the 5th time.)  Then we 
>>> bought a used one off of ebay.  (Tracking down a used drive on ebay with 
>>> documented proof of the correct high speed firmware, when the sellers have 
>>> no clue, is also another annoying trick to perform.)
>>> 
>> I bought a $79 eBay special VFD for my Bridgeport R2E3 retrofit. The entire 
>> programming sheet was one large sheet of paper.  I wanted to program torque 
>> boost at the low-end. I could do that, but then the motor had an overcurrent 
>> at full speed.  There needed to be a breakpoint where the torque boost faded 
>> out, but I couldn't figure out how to set that.  So, I finally broke down 
>> and spent more money on one from Automation Direct.  It came with a 90+ page 
>> book that had all the parameters listed, and showed how they interacted.  
>> Very good, clear and understandable.
> 
> And worthless w/o that.
> 
>> There are arms controls on high frequency VFDs.
> 
> Yeah the ITAR stuff IIRC. The one that came as OEM on the 6040 didn't do 
> anything it was told, ran in random directions etc. I threw it in the trailer 
> and bought a $120 clone on ebay. Its done as it was told for around 5 years 
> now. But its been changed once as the OEM motor was 120 volt and I was going 
> blind from the blinking shop lights so when the 120 volt motor bearings went 
> out, 3 or 4 hours running, the whole thing was replaced by 250 volt 4 bearing 
> stuff. One session with bad water I had to learn about, should still modify 
> it with a deionizer. but its not plugged up the motor,,, yet...  That 6040 
> has stepper/servo's on the Z and B axises. the Z because the 4 bearing motor 
> is bigger and heavier so stock couldn't lift it, same size motor in 
> stepper/servo picks it up at 60 ipm. And has never faulted. B axis is another 
> stepper/servo, follows the Y at 400 rpm carving vice screw threads in perfect 
> sync. 4mm tall buttress threads, 50mm in diameter two start, 12mm pitch in 
> hard maple. 3NM motors on 5/1 worms, chucks, shaft adapters, mounts, all 3d 
> printed, works great. And no (expletive) PID's in sight. They do exactly as 
> the tp or motion tells them to do.  Sweet.
>> Jon
> 
> Take care & stay well Jon.
> 
> Cheers, Gene Heskett, CET.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> 
> 
> 
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Re: [Emc-users] Not so slight problem with spindle/tools

[Dave Engvall]

Indeed, using drive dog threaded holes. Initially I did think about a flat disc 
but cannot see that gives me 
 any better holding strength than the dogs with a slight tee on top so one gets 
both drive and cat40 retention.

The other problem is keeping the  spindle from rotating while I torque down the 
tool. 
Tool holder is a Cat40 SK16 which gives me better rigidity than a ER collet. 
The concept is
to use AlCrN coated tools with coolant in hopes of getting decent tool life. A 
local shop is getting 
about 5000 feet of path length/cutter but also using coolant! Even with light 
cuts that is moving a 
lot of material in my case 8620 or 20 carbon steel, not too challenging.


> On Mar 18, 2024, at 5:26 PM, andy pugh  wrote:
> 
> On Mon, 18 Mar 2024 at 21:13, Dave Engvall  wrote:
> 
>> So I’ve built Tee-nuts that will retain the cat40 assuming the
>> M6 shcs hold. Planned use is to use small tools at max spindle speed.
>> (4K). I need ideas to clamp the cat40 so I can torque down tool while in
>> the spindle.
>> 
> 
> I am not 100% sure what you are describing.
> 
> Are you saying that you are using some tapped holes in the spindle face to
> hold Tee nuts to retain the tooling? Or are you maybe using the drive dog
> threaded holes?
> 
> Whilst a proper repair to the drawbar seems like the correct fix, I think
> that a machined ring to retain an ER collet holder might be better than
> what I think you are describing.
> 
> (Then you can just swap tools and collets)
> 
> -- 
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is designed
> for the especial use of mechanical geniuses, daredevils and lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
> 
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[Emc-users] Not so slight problem with spindle/tools

[Dave Engvall]

On my Muzak the belleville stack is too far gone to retain tools. Access is 
from the top which means removing the spindle motor, and transmission a 
nontrivial task. A couple of years earlier model everything came out the bottom 
and would have been a much easier job. So I’ve built Tee-nuts that will retain 
the cat40 assuming the
M6 shcs hold. Planned use is to use small tools at max spindle speed. (4K). I 
need ideas to clamp the cat40 so I can torque down tool while in the spindle. 
Any inspiration?

Dave

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Re: [Emc-users] Axis direction

[Dave Engvall]

> On Feb 5, 2024, at 6:19 PM, gene heskett  wrote:
> 
> On 2/5/24 18:26, John Dammeyer wrote:
>> Thanks everyone.  On the Unimat list there were a number of people really 
>> pushing the idea that Z+ was towards the chuck and it just didn't make 
>> sense.  And as we all know, nowadays once can find an internet source that 
>> supports almost anything.
>> Now if only the wand with the partridge feather core would arrive.  I'm sure 
>> the site selling it was not a con job.
> 
> That bit of humor John, reminds me a a msg I got from Ray Henry a day or so 
> ago. Said he wished he had known that a snow blower purchase was good at 
> warding off snow he would have bought one 20 years ago. He is in the UP and 
> has only had 1, 2" snowfall since buying a blower
> 
   If that really worked it might be worth it as we age. :-)
I
> I'm in WV and had 16" on the front deck about 2 weeks ago. Long gone now of 
> course.
> 
>> John
>>> -Original Message-
>>> From: andrew beck [mailto:andrewbeck0...@gmail.com]
>>> Sent: February 5, 2024 3:05 PM
>>> To: Enhanced Machine Controller (EMC)
>>> Subject: Re: [Emc-users] Axis direction
>>> 
>>> Same here every machine I have used (12 years CNC machining).  negative z
>>> is always towards the chuck.
>>> 
>>> Or on a mill brings the tool down to table. Or table up towards tool
>>> 
>>> 
>>> 
>>> On Tue, 6 Feb 2024, 09:23 Sam Sokolik,  wrote:
>>> 
 Even the k with a discrete component 60's control had smaller numbers
 towards the spindle...
 
 On Mon, Feb 5, 2024, 1:36�PM 
>>> wrote:
 
> 
> John,
> 
> Leaving aside right or left hand rules etc, leaning your head towards
> your left shoulder shows that the relationship between the spindle and
> the carriage is the same as on a vertical mill.
> To bring the spindle closer to the carriage is a move in the -Z
> direction.
> If the argument is about the tool position, with the work in the chuck,
> tilt your head to the right and you now have the tool on the right and
> the work on the left, like a mill with the tool above (on the right) and
> work in the chuck below (on the left0. Now the movement of the tool
> towards the work is still -Z.
> 
> Marcus
> 
> 
> On 2024-02-05 18:01, John Dammeyer wrote:
>> There's been an interesting discussion on the Unimat users list about
>> axis direction.  As usual someone can always find something on the web
>> that supports their opinion.
>> For example this one:
>> https://digit-chain.com/names-of-axes-in-cnc-machine/
>> 
>> However I disagree that movement towards the rotating axis, be it the
>> chuck on a lathe or the spinning cutter in a mill spindle,  is a Z+
>> direction.  Doesn't even seem intuitive to me either.
>> 
>> Now it's true that you can set the Z=0.00 position anywhere in the
>> G54... spaces depending on what you touch off on.  And then a
>>> movement
>> toward the spindle could be positive.  But in an G53 machine
>> coordinate space isn't a Z- direction towards the spinning tool or
>> part?
>> 
>> That's the way I have my LCNC system and MACH system set up.  Even
>>> my
>> ELS is negative towards the lathe chuck.
>> 
>> John
>> 
>> 
>> 
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> 
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 ___
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>>> 
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> 
> Cheers, Gene Heskett, CET.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> 
> 
> 
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Re: [Emc-users] where to nuy gears

[Dave Engvall]

Stockgears.com makes plastic gears. However, they seem expensive to me. 
Been years since I’ve seen a price list. 

Dave

Ps. Had to pull out a small cutting board they made as advertising to remember 
the name. ;-)


> On Mar 4, 2024, at 9:30 AM, andy pugh  wrote:
> 
> On Mon, 4 Mar 2024 at 17:02, fxkl47BF--- via Emc-users
>  wrote:
>> 
>> i'm looking for retail suppliers of straight internal spur gears
>> imperial and/or metric
>> other than sdp-si.com
> 
> https://www.hpcgears.com/n/products/6.internal_gears/internal_gears.php
> 
> 
> -- 
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
> 
> 
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Re: [Emc-users] Capto

[Dave Engvall]

Just cheat a bit. If you are belt driven then put a small idler/tensioner 
pulley arranged to be driven by the main belt.  
On the Mazak the servo motors had resolvers built in: with a 1:7 gear to 
increase the resolution .

> On Jan 4, 2024, at 7:14 AM, Sam Sokolik  wrote:
> 
> We had gotten some 5000 line - 2 count encoders on ebay a while back.
> It certainly helped..  Higher would be nicer.,.(for bigger diameter testing)
> 
> sam
> 
> On Thu, Jan 4, 2024 at 9:08 AM andy pugh  wrote:
> 
>> On Thu, 4 Jan 2024 at 13:39, gene heskett  wrote:
>> 
>>> Humm, that may call for a higher resolution spindle encoder than I have
>>> on my Sheldon,
>> 
>> I have a resolver on the spindle of my lathe, which the Mesa 7i49
>> converts into a 14-bit number, so should have enough resolution.
>> (linearity of the resolver is not something that I have ever tested)
>> 
>> But I don't quite understand why you are worrying about whether you
>> can make Capto shanks on your Sheldon?
>> 
>> --
>> atp
>> "A motorcycle is a bicycle with a pandemonium attachment and is
>> designed for the especial use of mechanical geniuses, daredevils and
>> lunatics."
>> — George Fitch, Atlanta Constitution Newspaper, 1912
>> 
>> 
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> 
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[Emc-users] Wandering in the wilderness

[dave engvall]

Hi all,
I've pretty much finished the mechanical side of a add-on Y axis for my 
small mill. New axis is 25 mm rails,  2 nm stepper-servos and glass 
scales as quality control only.
I have a Dell 790 with Debian 9 RT with Buster uspace. Hardware is 5i25 
and single 7i76. Boots and comes up in sim mode which pretty much 
confirms that I need to flash the card. I need 3 axes of stepper for the 
stepper servos plus estop and not much else. I'm planning on soft limits 
plus rubber energy absorbers at axis mechanical limits.

Will do Armstrong tool change. So what is a best choice for the bit file?
Comments and advice please.
Thanks.

Dave




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[Emc-users] Progress!

[dave engvall]

HI all,
I've been occupied in building a new Y axis to go on top the x of my 
contourmaster. Nothing like jousting with windmills.
1" rails on top of a cold drawn/hot roll frame.  5/8" ballscrew. With 
the spindle as reference I get about a half thou deflection leaning on 
the axis in the y direction and about a thou in the X direction. We'll 
see how this works in practice.

Aux readout from a set of chinese glass scales to add interest. ;-)

Now with that done I need to hook up the stepper=servos.
My brain seems to have gone on  holiday.
Controller is 5i25/7i76
http://servo.xlichuan.com/Private/ProductFiles/470763d1b2947213fdc2.pdf

I know the board is well protected but I'm not one to just hook things 
up and hope the magic

smoke is well contained. ;-)

Thanks

Dave





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Re: [Emc-users] Running PathPilot on non-Tormach Machines

[dave engvall]

Different strokes for different people.
Tormach supplies a niche market and is surviving. :-)
I went the other way and bought a machine with a dead control at 
auction. Trucked it in, shoved it thru the door of my shop and then 
spent the next year getting it running, New servo amps, servo-to-go 
card,  encoders on the ballscrew, etc. Not for someone that wants a 
turnkey op. Resale is not good; e.g. Mazak converted at Galesburg went 
out the door for way under 1K$ and that had the tool change working, new 
driver cards, and I think new amps. Labor of love or a challenge but 
certainly not a business opportunity!


I must admit the subject prompted a lot of traffic.

Dave
On 1/26/23 8:45 AM, ken.stra...@sympatico.ca wrote:

Nor do I! That is why I sent a pile of cash to Tormach instead of trying to
roll my own. It just works and allows me to make chips without worrying
about editing files or applying updates that break things or... Others
obviously favour different choices!

-Original Message-
From: Stuart Stevenson 
Sent: January 26, 2023 11:38 AM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Running PathPilot on non-Tormach Machines

  "Define a set of hardware that works and make their own distribution with
only one user interface.  It doesn't surprise me that nobody wants to do
this thankless task."

Perhaps thankless but Tormach has built a presumably profitable business by
doing exactly that.

And then packaging and selling the hardware to match.
An added dimension many (me included) do not want to tackle.

Overall, I am very impressed (and satisfied) with the capability and
progress.

thanks
Stuart


On Thu, Jan 26, 2023 at 9:33 AM  wrote:


"Define a set of hardware that works and make their own distribution
with only one user interface.  It doesn't surprise me that nobody
wants to do this thankless task."

Perhaps thankless but Tormach has built a presumably profitable
business by doing exactly that.

-Original Message-
From: Eric Keller 
Sent: January 26, 2023 10:01 AM
To: Enhanced Machine Controller (EMC)

Subject: Re: [Emc-users] Running PathPilot on non-Tormach Machines

On Thu, Jan 26, 2023 at 8:24 AM  wrote:


To me this is the minimum level of magic required to make a
commercially viable product. The vast majority of potential users
are uncomfortable (or don't want to bother) with manually modifying
configuration files. Of course the power of LinuxCNC is due to the
possibility of configuring things for all sorts of hardware. Without
magic the flexibility means that it will never be mainstream.

Nobody wants to give up the flexibility though.  The problem that lcnc
has is aptly summarized in this thread where someone gave up because
they wanted to use an Rpi4 and ethercat.  That's fine, and there are
plenty of people that have ethercat running with lcnc, maybe even on a
Rpi4.  But both the
Rpi4 and ethercat require a bit of messing around, I think, and
neither are really mainline lcnc.  Getting a 3 axis running on a Mesa
board on a PC with decent latency (another sticking point,
unfortunately) is trivial.  Someone mentioned 4 axis.  The problem
with that is that everyone has their own 4th axis.  This is also the
problem with lcnc in general.  I would say more than 90% of the
problems I see with people having trouble setting up lcnc is they have
a totally nonstandard install that wouldn't work with any other
software either.  So they can't get it to work with lcnc, buy
something standard, and go install Mach. And then badmouth lcnc any
time the subject comes up.

The people that want to make lcnc more popular could do something
about it, I think.  Define a set of hardware that works and make their
own distribution with only one user interface.  It doesn't surprise me
that nobody wants to do this thankless task.
Eric Keller
Boalsburg, Pennsylvania


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Re: [Emc-users] Home switches for LinuxCNC on a Lathe

[dave engvall]

I did something similar on a BP sized mill. Manually move x and y to 
roughly center the beam of a laser diode in a 3 mm hole in a tab at one 
end of the mill. Kick off homing for x and y and it will pick up the 
first index on each axis. You can then move from there to where your 
preferred zero is. I think one can do something similar with glass 
scales but they tend to have several (3) guard lines each side of the R.


Dave

On 12/4/22 5:25 AM, Stuart Stevenson wrote:

You might try the FADAL mill method.

They use two arrows (markers). One on the moving member and one on the
unmoving member. You physically align the arrows and run the home routine.
The next found index mark on the encoder is the home position.

regards
Stuart


On Sun, Dec 4, 2022 at 1:25 AM gene heskett  wrote:


On 12/3/22 22:56, John Dammeyer wrote:

  From what I understand you're talking about a normal parallel lathe so

here

are my thoughts:

Yes.  And thank you.

The Z axis is more interesting.  Before homing I imagine the tail stock
has to be loosened and moved all the way to the right as far away from

the

headstock to ensure finding a home switch.  Or a home switch could be
somewhere in the middle but then which direction to search?


I think the safest setup  in this case (given your Z axis can crash with
the tailstock if you forget to move it all the way to the right) will be
having the home switch towards the chuck side (with a proper
independent limit switch right at the left of the home switch to avoid
crashes when homing). This way you can set up your homing sequence to

first

home the X axis to move it to a safe place and then home the Z axis

towards

the chuck.

I'm guessing you are suggesting something like what Gene was that the

home switch isn't at the end of travel but somewhere else and once
activated never goes inactive in that same direction.   So if you start a
home sequence and the switch is ON you know you have to go to the right
until it goes OFF.  It can't over travel past the OFF position and go ON
again.  That approach lets the Home Switch be pretty well anywhere.

Unless the limit switch is movable it's useless.  My carriage can go

much further to the left to turn near the part held in the 5C collet than
it can with the part held in the 3-Jaw.  So a crash into the spinning 3-Jaw
can happen without ever touching the limit.  And if the limit does prevent
that one can't turn a part close to the collet.

How does one determine, with that tool tip, where the lathe centerline

is

and set that so G54 X is 0.000?


I think you're asking about tool setting. If you have tool fixtures that
ensure that whenever you change your tool you get the exact same tool
position then it's just like a CNC turret. You just take a skim cut on

the

diameter (or maybe use some fine paper to gauge the tool against the
workpiece) and then measure and input the diameter (or radius depending

if

you're in G7 or G8) in the touch off popup.


Thanks.  I'm going to have to study that a bit further.
I understand that the machine coordinate for x at the home switch is

0.000.

And measuring the tool tip relative to how it mounts into the AXA holder

can be done creating an offset from the home switch.v  Now each time the
tool holder +tool  is put into the AXA the distance from the tool table is
offset from that home position and LCNC knows where the tip and can turn a
diameter.  Theoretically.

However as  soon as the holder is pivoted even slightly the distance of

the tool tip relative to the home switch changes.   And it changes
differently depending on how far the tool protrudes out of the AXA holder
right?

So the tool measurements are only useful with the AXA in one position

and that can change really easily in the home shop.  We're not talking a
commercial production operation where the setup is the same over a long
period of time.

I suppose if you can touch of or measure the new position of the tool

tip you can then use simple trig to determine the angle that the AXA holder
has pivoted.  Unless it also slid in the T-Slot which now moves it in more
than one dimension.

Doe my explanation make sense?  A small shop lathe where the operator

can shift the tool bit around relative to the X home switch and even on the
carriage relative to the Z home switch suggest a tool table for a LCNC
lathe is virtually impossible.

So I can manually turn that shaft.  Leave the X axis where it is and

measure the diameter; say exactly 1.000".   Then click on the "Touch Off"
on the display and enter half the diameter (0.5") for the offset.

Now a request to move the X to 0.480" to do a 0.020" deep pass should

work right?

But the tool table and for that matter the home switch and machine

coordinate system is pretty well useless.  Or have I missed something?

John



Don't adjust your antenna, you got it, John, the reception is perfect.
The main reason for a home sw is the let the machine know where its at
in the absolute sense, I've 

Re: [Emc-users] Deep slot chip removal

[dave engvall]

With an open machine I tend to us air rf vacuum to extract chips. One 
needs enough air movement to get turbulence for effective chip removal. 
I tend to start pockets, etc with a drill to within .02 of full depth. 
I've also drilled a pattern of holes to extract major volumes of 
material from pockets. However, just getting a good starting hole with a 
drill and then continuing with a mill is a smoother process.  In 
desperation mode blow air and catch the chips with vacuum much like a 
dentist does.


Dave

On 12/1/22 12:18 AM, Gregg Eshelman via Emc-users wrote:

Flood coolant, air blowing, or vacuum. Or pre-drill a bunch of holes to almost 
finished depth to remove the majority of the waste before milling.


On Wednesday, November 30, 2022 at 10:08:49 AM MST, Nicklas SB Karlsson 
 wrote:

Milling a deep pocket spiral down work great first turn but after a
while torque is not enough and mill stop. Suspect it is because mill
have to cut old chips in addition to machining part.

Maybe it is a good idea to use drill bit a little bit smaller than
slot?


Nicklas Karlsson


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Re: [Emc-users] losing encoder counts

[dave engvall]

This make a good case for dual independent encoders. motor 
shaft/ballscrew, ballscrew/glass scale, steps/glass scale, etc.
Just for grins I tried the hand crank on my well used (Boeing then trade 
school, the auction) defunct tracer mill converter by a Russian engineer 
to cnc for the trade school. 1963 vntage cinci. Comparing the hand crank 
on the X vs a accurite 5 um glass scale they were dead on (of course 
only in one direction) ;-) The Y was a mess so I didn't try it.
It is relatively easy to clamp a glass scale to the bed, dial it in 
parallel to the axis then tie it to the spindle with the spindle power 
carefully disabled and proceed with measurements. Notice I did not say 
much about a Chinese glass scale. Some are good some not so good. You 
pays your money and takes your chances.


Dave

On 10/5/22 7:53 PM, Jon Elson wrote:

Wow, it gets deeper!

It is NOT the encoder, or anything in the encoder-reading process.

I marked the motor shaft, and the motor is returning to the exact same 
position every cycle.


Well, I tried a different indicator and mount, and the problem was in 
the indicator mount!  I was using an old knock-off of an IndiCol that 
clamps around the spindle nose or end mill holder and has several rods 
with locking thumbnuts on them.  These swivel joints were slipping 
just a tiny bit each time the vise touched the indicator, even though 
they were PRETTY tight!  Ugh, 3 days of going around in circles trying 
to tell where the issue was!


Jon



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Re: [Emc-users] XSY inverters (VFD)

[dave engvall]

On 9/24/22 11:18 AM, gene heskett wrote:

On 9/24/22 11:34, Jon Elson wrote:

On 9/23/22 17:24, gene heskett wrote:
Each brand of vfd seems to have its own setup. But that lf boost is 
a tricky one. I don't know
if that invertor shows you the amperage being delivered but it seems 
it would be an odd one
if it didn't. What you normally do is read the motors nameplate for 
the FLA, Full Load Amperage.


Then set the lf boost to not exceed that.
Yes, I have found that the default current limit is 3 A, my 2 HP 
motor is rated at 6 A, so that was the reason for the trips.


If you intend to use it in both directions, quickly as in rigid 
tapping operations, the accel/decel
registers are generally set rediculously conservative. Those can be 
sped up to almost instant,

but lcnc can still confuse the vfd into tripping.


I have a lowpass filter on the spindle speed value in the HAL file.  
This has worked great on my old mill.  I did have to turn off the 
motor overheat integrator in the old VFD, as the Bridgeport motors 
can handle plug reversing.  I do 4-40 rigid tapping at 1000 RPM.  I 
will have to figure out how to do that on the new VFD.


Thanks,

Jon
I've not seen a register so named in any of the vfd's I've played 
with. They've all been 1.5 hp rated, driving 1hp rated motors. I'd 
never consider a vfd as "plug" reversable, as that puts it all in the 
time lag to trip the'
service breakers. Delaying the reverse signal until the motor is 
stopped, shifts all those surges into the
filters in the drive., and uses little or no mains power to effect the 
reversal. My mill draws around 5 amps
wide open, and an analog amprobe says it drops to around 2 amps during 
the reversal. Loaded and throwing
swarf all over the place it might peak at about 15-16, but the only 
indication I have that its working too hard, is when your driver goes 
into current limit at about 17.5 amps of DC into the motor. With a 
pid-p at 25 or so
there is no slowdown as the current goes up, until I hear the squeak 
from the motor iron as your driver limits.:)


Those gears in the go704 head are nylon, and I'm still amazed I 
haven't broken them. Among other things
in controlling it,  I used a mux4 for the speed change vs tach scale 
and such, so there's 4 inputs to control
speeds. Two inputs from tally switches watching a notch in the rim of 
the gear shift knob control what gets
fed to the limiter in front of the pid_S input. When neither switch is 
true, a speed of about 25 rpms is
fed to the motor.  By this means, it can be doing 3000 at the spindle, 
I can grab the knob and the tally
goes false in maybe 2 degrees, leaving the motor turning very slow 
while I'm changing gears, those
gears all have square sided teeth, the slow turning engages the gears 
with no hesitation I can feel, and
the tally does not go true until 98% engaged. So I can reach up and 
change gears on the fly at any rpm.
Before, I had to stop the spindle, then grab the spindle and turn it 
by hand in order to engage the new

gear. Then restart the spindle.  Now I just turn the knob.

Picky little stuff, Jon, but its safer too.

I bough me a circular square to use to make the post square to the 
bed, its leaning about 2 degrees,
but have been occupied with the 6040 as I teach it how to make a BIG, 
LONG, hard maple workbench
vise screw. And trying to get a 2nd 3d printer to work with PETG in 
various flavors to make the buttress

thread nut and such.

Some pix of it are on my web page in the sig.  John K. won't let me 
post them.


Take care and stay well now.

Cheers, Gene Heskett.
The controller for the spindle motor on the Mazak changes field current 
relative to spindle speed. I don't suppose there are any hooks to do the 
same for the XSY inverter. Just a random thought.


Dave


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Re: [Emc-users] missing tooth index questions..

[dave engvall]

This may be a bit wild  but use pll and trigger when the expected pulse 
doesn't appear. Maybe a bit far out of the box.

Basically the reverse of synchronous detection.
D

On 9/18/22 1:59 PM, Sam Sokolik wrote:

in case that screenshot didn't come through

https://electronicsam.com/images/emco/Screenshot%20from%202022-09-18%2015-43-25.png

On Sun, Sep 18, 2022 at 3:50 PM Sam Sokolik  wrote:


I have a optical encoder from a mouse running on an emco encoder wheel
(100 holes).  I cut out the metal between 2 holes.  I think that would be
considered one missing tooth...  I have the encoder scale set to 100 and
the missing tooth set to 1

I have a little comp that sets the index enable to true whenever it is
false.

Looking at the halscope screen shot - it only counts to 98..  I would
think it would count from 0 to 99.  You can see the gap is seen - but I
think there should be an extra count in there..

(I could be not understanding it too)

ps - if I set the missing teeth to 2 - it will not trigger (like it
doesn't see the gap then which seems correct)

thanks!
sam


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Re: [Emc-users] Pocket milling

[dave engvall]

indeen! Spiral out from center going as deep as possible and constand 
radial engagement. When that is exhausted them
try same idea on the triangular remanents. Then go back and test that 
against Jon Elson's code. Machining is an experimental science. Eh?


Dave

On 9/18/22 12:18 PM, Nicklas SB Karlsson wrote:
I was not thinking to much about the corner. If machining with for 
example 50% tool engagement then end is reached machining at 90 
degrees into material and tool engagement increase to 100% before next 
pass. An alternative would for example be to machine into material 
with an angle.


For the first pass tool engagement will always be 100% so maybe start 
in the middle spiraling outwards is a good choice to keep tool 
engagement at the desired value is a good choice?



Den 2022-09-18 kl. 18:57, skrev dave engvall:

Hi Nicklas,
Just a WAG, offset cutter maybe .25 mm from real corner and plunge 
then clean up in incrementally with a couple of passes to clean out 
the wings. I think most cam programs just take light passes including 
the finish pass.
How stiff the spindle is and sharpness of the cutter are still 
critical. Slowing feed on final pass should also help.
Another approach might be to use a roughing cutter of the equal to 
the final radius and mill out as much as you can without overcutting 
then clean up with a regular end mil. Unless you have a really tight 
machine your plunge cut and final pass will not be equal. Don't ask 
me how I know. ;-)

This advice. is of course, worth about what you paid for it.

On 9/10/22 2:51 AM, Nicklas SB Karlsson wrote:
Then pocket milling with tool engagement less than tool diameter for 
some patterns tool engagement increase to tool diameter in the 
corners or ends. Anybody have anyone have any experience or 
knowledge how to handle this situation?


Nicklas Krlsson



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Re: [Emc-users] Pocket milling

[dave engvall]

Hi Nicklas,
Just a WAG, offset cutter maybe .25 mm from real corner and plunge then 
clean up in incrementally with a couple of passes to clean out the 
wings. I think most cam programs just take light passes including the 
finish pass.
How stiff the spindle is and sharpness of the cutter are still critical. 
Slowing feed on final pass should also help.
Another approach might be to use a roughing cutter of the equal to the 
final radius and mill out as much as you can without overcutting then 
clean up with a regular end mil. Unless you have a really tight machine 
your plunge cut and final pass will not be equal. Don't ask me how I 
know. ;-)

This advice. is of course, worth about what you paid for it.

On 9/10/22 2:51 AM, Nicklas SB Karlsson wrote:
Then pocket milling with tool engagement less than tool diameter for 
some patterns tool engagement increase to tool diameter in the corners 
or ends. Anybody have anyone have any experience or knowledge how to 
handle this situation?


Nicklas Krlsson



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Re: [Emc-users] Linuxcnc OEM?

[dave engvall]

One has to remember that emc was written not as a machine controller but 
to demonstrate
the concept of communication between machines. In like manner steppers 
were an add-on.
Linuxcnc is only alive today because of a critical mass of dedicated 
volunteer programmers.


Dave
On 7/21/22 2:32 AM, andy pugh wrote:

On Thu, 21 Jul 2022 at 03:22, Charles Steinkuehler
 wrote:

I'm not sure of their international shipping details, but Probotix sells
LCNC based routers:

https://www.probotix.com/

Which mentions that they have (amusingly) sold LinuxCNC systems to NIST. :-)





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Re: [Emc-users] Clausing NC Spindle drive belt tension and noise.

[dave engvall]

Indeed! Poly-Vee belts are acceptably quiet but of course then you need 
to rig an encoder.
Probably a decent trade  off.  Available, not too expensive, transfer 
power well and seem to last.

Years ago I made both of my pulleys.

Dave

On 7/4/22 10:05 AM, andy pugh wrote:

On Mon, 4 Jul 2022 at 17:04, John Figie  wrote:


https://www.roll-ring.com/?lang=en


Andy, That is a nice idea. However in my case I don't think I would
have clearance.

It could go at the bottom, nearer the drive motor.

The belt on my Holbrook is a rather wide poly-vee. Very quiet. I have
a much smaller, small pitch toothed belt to drive the encoder.





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Re: [Emc-users] spindle problem

[dave engvall]

Hi Todd and others;
Indeed it is a horrible idea but I feel backed to the wall.

I have T lugs but they are secured by M6 shcs which is no where close to 
as strong as the normal retention stud. However, I plan to use the 
machine at full rpm with AlCrN coated end mill,

coolant and keep the loading low.
I don't have much to lose. My chances of living more than 10 years more 
are not good and that assume health good enough to work in the shop.


Dave


On 6/27/22 7:25 AM, Todd Zuercher wrote:

Gluing a spindle taper into a spindle sounds like a truly horribly idea.  (I'd 
be more worried about it letting go when you didn't want it to, than trying to 
get it out later if you did want to remove it, although that also may prove 
problematic.)

The drive lugs are usually removable/replaceable.  Maybe you could make new 
drive lugs that also positively engage the tool holder to retain it.  Something 
like a longer T shape that would capture the tool holder flange.  (Personally 
I'd do every thing I could to fix the spindle properly though.)

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031

-Original Message-
From: dave engvall 
Sent: Monday, June 27, 2022 9:57 AM
To: emc-users@lists.sourceforge.net
Subject: Re: [Emc-users] spindle problem

[EXTERNAL EMAIL] Be sure links are safe.

Update: The drive lugs get in the way of a safety disk or ring or anything 
else. Epoxy looks more promising; just a semi-permanent solution.
Note: Epoxy can always be removed with heat or chlorinated solvents but...
Dave

On 6/27/22 6:27 AM, dave engvall wrote:

Back again;
Since crawling in under the spindle is difficult for an old stiff guy
I laid the iphone on the table and took a pic, rotated the spindle 45
degrees and took another; nothing useful moved. However, there are
large socket head cap screws around the perimeter of the spindle. It
should be possible to make a safety cap that has a few thou clearance
to limit axial movement. 'Maybe' I can jury rig something. Basically I
have to see what kind of clearances I have. An actual thrust bearing
seems like asking for trouble.
Psychologically it would almost be easier to pick up the radiator cap
and run a new(er) one in. Still that brings all sorts of problems of
its own. Hard to win.
Back to the drawing table. ;-)
Dave

On 6/26/22 9:10 AM, andy pugh wrote:

On Sun, 26 Jun 2022 at 15:45, dave engvall  wrote:


A couple of solutions present themselves but neither are ideal.
Simply use the M6 shcs that hold the dogs in place to secure the CAT40.
Balance and adequate strength/safety would seem to present problems.

Does the nose have any extra holes? There are 4 threaded holes with
no obvious function on my 30INT spindle and looking around the
internet I see threaded holes in some of the CAT40 spindles.
It seems that you could use those to hold in a custom ER40 (or
similar) adaptor.

4000 rpm probably isn't fast enough to need to worry too much about
balance.





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Re: [Emc-users] spindle problem

[dave engvall]

Update: The drive lugs get in the way of a safety disk or ring or 
anything else. Epoxy looks more promising; just a semi-permanent solution.

Note: Epoxy can always be removed with heat or chlorinated solvents but...
Dave

On 6/27/22 6:27 AM, dave engvall wrote:

Back again;
Since crawling in under the spindle is difficult for an old stiff guy 
I laid the iphone on the table and took a pic, rotated the spindle 45 
degrees and took another; nothing useful moved. However, there are 
large socket head cap screws around the perimeter of the spindle. It 
should be possible to make a safety cap that has a few thou clearance 
to limit axial movement. 'Maybe' I can jury rig something. Basically I 
have to see what kind of clearances I have. An actual thrust bearing 
seems like asking for trouble.
Psychologically it would almost be easier to pick up the radiator cap 
and run a new(er) one in. Still that brings all sorts of problems of 
its own. Hard to win.

Back to the drawing table. ;-)
Dave

On 6/26/22 9:10 AM, andy pugh wrote:

On Sun, 26 Jun 2022 at 15:45, dave engvall  wrote:


A couple of solutions present themselves but neither are ideal.
Simply use the M6 shcs that hold the dogs in place to secure the CAT40.
Balance and adequate strength/safety would seem to present problems.

Does the nose have any extra holes? There are 4 threaded holes with no
obvious function on my 30INT spindle and looking around the internet I
see threaded holes in some of the CAT40 spindles.
It seems that you could use those to hold in a custom ER40 (or
similar) adaptor.

4000 rpm probably isn't fast enough to need to worry too much about 
balance.







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Re: [Emc-users] spindle problem

[dave engvall]

Back again;
Since crawling in under the spindle is difficult for an old stiff guy I 
laid the iphone on the table and took a pic, rotated the spindle 45 
degrees and took another; nothing useful moved. However, there are large 
socket head cap screws around the perimeter of the spindle. It should be 
possible to make a safety cap that has a few thou clearance to limit 
axial movement. 'Maybe' I can jury rig something. Basically I have to 
see what kind of clearances I have. An actual thrust bearing seems like 
asking for trouble.
Psychologically it would almost be easier to pick up the radiator cap 
and run a new(er) one in. Still that brings all sorts of problems of its 
own. Hard to win.

Back to the drawing table. ;-)
Dave

On 6/26/22 9:10 AM, andy pugh wrote:

On Sun, 26 Jun 2022 at 15:45, dave engvall  wrote:


A couple of solutions present themselves but neither are ideal.
Simply use the M6 shcs that hold the dogs in place to secure the CAT40.
Balance and adequate strength/safety would seem to present problems.

Does the nose have any extra holes? There are 4 threaded holes with no
obvious function on my 30INT spindle and looking around the internet I
see threaded holes in some of the CAT40 spindles.
It seems that you could use those to hold in a custom ER40 (or
similar) adaptor.

4000 rpm probably isn't fast enough to need to worry too much about balance.






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Re: [Emc-users] spindle problem

[dave engvall]

Hi Roland,
I thought about using a friend but I tend to outlive them. Lost a couple 
lately that would have been ideal. That is the trouble with getting old. 
;-)
If the machine were in a nice open shop where just running in a tall 
forklift and picking up the
transmission, etc and lifting it off to the side it indeed would be 
easier. What would have been not too difficult 10 years ago is somewhat 
intimidating now.

'Sides I'm not the best supervisor.
Still thanks for the idea.

Dave

On 6/27/22 4:09 AM, Roland Jollivet wrote:

Surely you could hire a buff mechanic from down the road and totally
supervise/instruct him what to do?


On Sun, 26 Jun 2022 at 16:45, dave engvall  wrote:


Hi,
My Mazak V5 has been down for a few years. First for brushes on the
spindle motor and then a much more serious broken belleville stack.
Unfortunately, the spindle on this model comes out from the top which
means pulling all the hydraulics and the spindle motor/transmission and
getting them out of the way. I don't see that is it possible to replace
the stack w/o fussing with all of the above.
Note: I'm 4 score and 4 and not as energetic as I used to be.
A couple of solutions present themselves but neither are ideal.
Simply use the M6 shcs that hold the dogs in place to secure the CAT40.
Balance and adequate strength/safety would seem to present problems.
The other solution is to simple punt and epoxy a CAT40 in place and live
with the restrictions.
Candidate CAT40 is a SK16 with holders for end mills up to M16 and at
least consider adding an ER20//ER16 with a M16 stub (custom dia) to
drill/ream. I have sets of ER20 and ER16 collets.
Note: spindle is 4000 rpm and 5 HP geared.

If anyone has a better idea I'm all ears.
As usual TIA: I seem to be out of easy/ideal solutions.

Dave


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[Emc-users] spindle problem

[dave engvall]

Hi,
My Mazak V5 has been down for a few years. First for brushes on the 
spindle motor and then a much more serious broken belleville stack. 
Unfortunately, the spindle on this model comes out from the top which 
means pulling all the hydraulics and the spindle motor/transmission and 
getting them out of the way. I don't see that is it possible to replace 
the stack w/o fussing with all of the above.

Note: I'm 4 score and 4 and not as energetic as I used to be.
A couple of solutions present themselves but neither are ideal.
Simply use the M6 shcs that hold the dogs in place to secure the CAT40. 
Balance and adequate strength/safety would seem to present problems.
The other solution is to simple punt and epoxy a CAT40 in place and live 
with the restrictions.
Candidate CAT40 is a SK16 with holders for end mills up to M16 and at 
least consider adding an ER20//ER16 with a M16 stub (custom dia) to 
drill/ream. I have sets of ER20 and ER16 collets.

Note: spindle is 4000 rpm and 5 HP geared.

If anyone has a better idea I'm all ears.
As usual TIA: I seem to be out of easy/ideal solutions.

Dave


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Re: [Emc-users] cable connector for lcda357H stepper_servo

[dave engvall]

 Mucho thanks everyone for all the help. Ebay looked good but fallback 
would be Digikey.

Note: I'm not tight, I just squeak a little when I walk.
Have an order in for 5 in case I need spares.

Dave

On 5/23/22 2:40 PM, gene heskett wrote:

On Monday, 23 May 2022 15:01:15 EDT Rob C wrote:

If it's the green connector, just search google for 6 pin 5.08 mm screw
terminal and you will get these sort of hits:
https://www.amazon.co.uk/dp/B0924QD2T2?tag=amz-mkt-chr-uk-21=
1ba00-01000-org00-win10-other-smile-uk000-pcomp-feature-scomp-feature-s
comp=aa_scomp

This link above is the wrong size, its too big.

This s/b the digikey for this 3.81 mm sized plug:
<https://digikey.com/en/products/detail/phoenix-contact/1803617/260533?
utm_adgroup=Terminal Blocks - Headers%2C Plugs and
Sockets_source=google_medium=cpc_campaign=Shopping_Product_Connectors%2C
Interconnects_term=_content=Terminal Blocks - Headers%2C Plugs
and
Sockets=EAIaIQobChMI4K2wmsn29wIVocmUCR1IxAjXEAsYAiABEgIxmPD_BwE>


https://www.google.com/search?q=6+pin+5.08+screw+terminal=1C1GCEA_e
nGB928GB928=ALiCzsZ_Zu8IuD736JHpZK01OeIrOj8YVw:1653332340188
ce=lnms=isch=X=2ahUKEwi7mdT2pvb3AhXDoFwKHbE_BeQQ_AUoAXoECAEQ
Aw=1229=531=1.56
On Mon, 23 May 2022 at 19:58, Rob C  wrote:

Is this the green connector plug?

On Mon, 23 May 2022 at 18:57, andy pugh  wrote:

On Mon, 23 May 2022 at 18:41, dave engvall 

wrote:

Can anyone provide a part number, eg. manufacturer or digikey, etc
number for the 6 pin encoder cable connector on the LCDA357H
controller.>>

Google has shown a number of options (including DE-09)

Can you find a photo, and measure the pin pitch?

--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Cheers, Gene Heskett.




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[Emc-users] cable connector for lcda357H stepper_servo

[dave engvall]

Hi all,
Can anyone provide a part number, eg. manufacturer or digikey, etc 
number for the 6 pin encoder cable connector on the LCDA357H controller. 
It should be identical to the cable end for the 6 pin connector for 
pul+, plu-, etc.

As always I appreciate the help. As I age I seem to need more of it. ;-)

Dave


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Re: [Emc-users] Do pnp prox switches need a pulldown load R?

[dave engvall]

Indeed!  Positional is critcal and useful.
D

On 5/12/22 2:07 PM, Gregg Eshelman via Emc-users wrote:

Go traffic lights in Japan used to be blue. There may still be some blue ones 
in out of the way places. When the country adopted the international color 
standard for traffic light colors, supposedly their department in charge of 
such things chose the bluest shade of green they could get by with.


The plain old traffic light can be a bother for people who are red-green color 
blind. They have to note the position of the light rather than the color. Might 
be more of an issue with horizontally positioned ones, especially when at a big 
intersection with multiple lanes and lights.

What you don't want to do is drive with red sunglasses that are the perfect 
shade to 100% block the color of stop lights. Can't tell they're on at all so 
you have to know that when you see no lights, the red one is on.

On Thursday, May 12, 2022, 08:21:29 AM MDT, Chris Albertson 
 wrote:

On Wed, May 11, 2022 at 3:03 PM gene heskett  wrote:


I suppose in some circles that bleached red could be called brown. But
blue has never been ground on this side of the pond. Which is odd, in
electrical wireing, black is hot, white is neutral/ground, a static
ground is green. Inside a radio, black is ground.


Yes, that is how it works in the US.  But they did other things
differently in the US too.  Like using inches and yards to measure
distance.  At about 60+ I might be the youngest to remember US units like
feet used in engineering work.  When I was in school they still had us do a
few of the problems in US units.  They stopped using that soon after and
from the 80s all work was metric.

There might be a cultural reason for using blue for ground.  My wife
sometimes slips up and in English calls the "GO" light in a traffic signal
"Blue" even though the color is green worldwide.    Her first two
languages, when she grew up were Japanese and Chinese.

In English Green, Ground and Go all start with "G", so I'd guess that is
why we used green.  But that coincidence only works in English.


Chris Albertson
Redondo Beach, California


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Re: [Emc-users] OT but built on linuxcnc machines:) affordable color sensor for project (24v model)

[dave engvall]

I like the idea of a web cam, much better than single chips. Even better 
if one can split out the  RGB channels, in which case you get built-in 
filters. Still concerned about getting enuf contrast off a thin film of 
marker pen; fluorescence?  Glad it is someone else's problem.


Dave

On 5/11/22 10:30 PM, Chris Albertson wrote:

On Wed, May 11, 2022 at 10:08 PM Chris Albertson 
wrote:


You can do this with a  $20 webcam.  Any decent video camera will work,
especially if you take care to rig up good quality even, no-glare lighting


Sory I hit "send" too soon...

Sorting parts on a conveyor belt by color, size or shape is a classic
computer vision problem.It is possible that the software could find the
part if it is always in the different part of the belt.  What you do is
first locate the part, isolate te pixels that belong to it, then look at
and RGB histogram to determine color

The software you use is "OpenCV".   It is a library with hundreds of
functions, some for getting the video camera data into the computer.   You
could use either C++ or Python.








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Re: [Emc-users] A bit OT: Looking for pinout for a Chinese Scale reader head

[dave engvall]

Indeed, it is an interesting approach.
http://www.shumatech.com/support/chinese_scales.htm#Scale%20Connector
It may be time to dig out the scope or to upgrade to newer scales and 
readout.
If the glass scale is very good then it is probably worth the fuss ... 
else
The chinese scales I got were good but not nearly as good as the 
accu-rite 150.
I've not been able to make the chinese scales play nicely with an 
accu-rite readout.
So I did the whole shebang in chinese as a manual readout X, Y, Z for my 
mill. Before I removed the X accu-rite scale I checked it at 1 inch 
intervals against the handwheel for the ballscrew.
This is a 1963 Cinci tracer converted to cnc and at this point back to 
manual. The handwheel checked to 0.001" re the  digital display.

Clearly YMMV.  Best wishes.

Dave




On 5/8/22 7:59 AM, Mark wrote:

Hi All,

I've got an elderly Shumatech DRO-350 and was using it this past week 
and the read head on the X axis of my mini mill decided it was time to 
give up the ghost. I ordered what looked to be a drop in replacement 
but when it arrived, I noticed it had a mini USB connector as it's 
data port. The old chinese scales used a plug that had four sprung 
strips that lay against four strips in the reader head. I'd been using 
a cable I got from Little Machine shop years ago that had that plug on 
the scale end, and a 4 pin mini DIN connector on the other that 
plugged into the DRO-350. Attached is a picture of the connection 
lines. Wondering if anyone knows what the pinout for the mini USB 
connector on the scale would be and if it would match up to the lines 
pictured below on the mini DIN. If so I can cobble together a cable 
that has the mini DIN on one and a mini USB on the other.


Thanks,
Mark


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Re: [Emc-users] Blown BOB and ???

[dave engvall]

Being used to servos the first thing I test is the estop. Saves damage 
to expensive mechanics.
Once I was testing a new interface. Running it from lower left to upper 
right. It was gaining about .1" every pass. ... after about 4 passes it 
took off for the upper corner at full speed: 400 ipm. My hand made it to 
the big red button ahead of the upper corner but knowing the axis estop 
limits were there and working gives piece of mind. Especially when the 
combined weight of the saddle and the table is 700 Kg.


Dave

On 5/1/22 8:59 AM, Chris Albertson wrote:

There is a good chance there was a wiring error in you original setup.  The
fact the E-stop did not work tells me there was a design error.  E-Stop
should never fail, or rather if it does fail, the machine stops.  If the
inputs on the drivers are blown, that says the same thing.  Smaething was
wrong as that should never happen.

Diagnosing a system that has a design fault is really hard because our
brain tends to think of how a correct machine would function or how the
machine we THOUGHT we built should function.

The best plan is to ignore LCNC the BOB and all for now and see if you can
drive the motor drivers with a simple signal generator and no computer.
  If this does not work, you need to replace or repair the drivers before
you think about reconnecting a computer.   If you need to buy some test
equipment, now is the time.At least a cheap square wave signal
generator and a cheap $12 logic analyzer t go with your multimeter.

Finally, you should draw a schematic of how you propose to connect the
computer and post it here for others to review.   They will check if
nothing else the e-stop design to see that it is failsafe and also check
that you have the power and computer parts properly isolated.   It seems
this may not have been the case in the past, and you don't want to simply
put it back the way it was.

First step is to verify the motors and drivers work independently of
computer control.



On Sun, May 1, 2022 at 7:53 AM Alan Condit  wrote:


Hi Guys,

I was machining a part on my X2 Minimill. Suddenly it left the programmed
track (spoiled the part) and didn’t respond to Estop. I powered the system
off manually raised the Z axis and tried turning it on so I could home it,
smoke started coming from the controller. So I powered everything down and
started troubleshooting.
There were two chips on the CandCNC Mini-IO BOB that had let out the magic
smoke. I had a spare BOB that I built using the Gecko G540 schematic. So I
replaced the other BOB with it. The drives in the controller are Superior
Electric SS2000MD4 drives.

When I got everything put back together and checked the wiring everything
looked good so I tried powering it up. When I tried homing it the traces
move in AXIS but there is no movement on the machine. The motors hold
position so the output of the drives is active. Is it likely that I blew
out the inputs on the drives?

Thanks,
Alan

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Re: [Emc-users] Do we have an m-code with access to halcmd?

[dave engvall]

Being a suspicious kind of guy I'd hang an encoder on the shaft and 
measure it.
Jon Elson makes an  interface that  passes thru the encoder counts on a 
panasonic servo motor with your electronics background you ought to be 
able to do the same for your servo.
Just thinking out loud which usually get me in trouble. So I'll open my 
mouth, then duck and run. ;-)

Dave0.36
Opps! contribution from the CAT.

On 4/29/22 6:01 AM, Thaddeus Waldner wrote:

Gene, can you share a link to the motor you are using?

Thanks


On Apr 29, 2022, at 3:46 AM, gene heskett  wrote:

On Thursday, 28 April 2022 21:17:20 EDT gene heskett wrote:

On Thursday, 28 April 2022 19:35:44 EDT andy pugh wrote:
On Fri, 29 Apr 2022 at 00:20, gene heskett 

wrote:

Surely you already know that? It's 360 x 100 x SCALE ?

Sure Andy. But what is the scale?

200 * 16 * 40 * (60/53) / 360

But these motors are not 200, but 300, they are 3 phase, 1.2 degrees a
full step. 300 steps per rev for full step.
So by purely mechanical means, that would then be:
300 * 16 * 40 * [60/53] / 360, or 603.7735849 according to my TI-36X
Pro. But thats about 5x what seems to be pretty close @ 125.x.
Something, someplace is lying like a rug. But where? You got the hal
file now, is it wrong?

Two problems to fix before its right.

1. These drivers have two microstep modes, digital and apparently powers
of 10. Only one switch is on, sw3, which claims it makes a full turn of
the motor in 6400 steps. Just one problem. A 300 full step per turn motor
cannot be made to equal 6400 with any integer multiplier. At /16, its not
6400, but 4800 steps per turn. A value that's off either by .75, or
1. depending on interchanging the numbers. If it is truely
actually 6400 microsteps/turn, what the hell kind of math is it useing?
Obviously NOT a power of 2. I think these little magic boxes are miss-
marked. Obviously whoever drew up that silk screen was thinking in terms
of a 200 full steps per turn motor, and the 3 phase models are 300, not
200. So that means 300*16 is 4800 steps per turn of the motor shaft. No
way in hell can I make the math work using thier silk screened figures.

So that's problem #1. And the correct answer can only be found if #2 is a
1/1 answer.

[edited]

I just found the stepgen drawings in the docs and I think my hal file
is wrong, the values presented by the position.fb pins are not in the
same units as .count's. position.fb has been scaled.

2. The $64k question then, since the step itself is not available to hal
for counting, is the stepgen a direct translator?, issueing 1 full step
per count it reports on the .count pin?
(yes/no)
If no, what is the ratio?


And this needs counts. I'll fix that when I get it back together. Then
maybe it will make sense.
currently stepgen3.counts is  -173640,
whilestepgen3.position.fb is  1380.7

Fixed already, but not yet exersized for truthfullness. A sneakernet
mistake. :o(

Thank you, Andy.

Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis





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Re: [Emc-users] Controlling DC motors.

[dave engvall]

Clearly OT!
Indeed electronics have   come a long ways since then.
I still have my Dad's 200 w-sec strobe. Oil filled caps from Edmund 
Salvage dumped to the flash tube with a thrytron. Later vintage an 
electronic ignition, nice toroid 6 v to 400 v converter and a decent SCR 
for my   PV544 (pregnant roller skate). Got me a gain of about 1.5 
mi/gal averaged over a year.  and a constant current supply ... that 
drove a 1:2 step up transformer to light 5 to 32 orchard heaters ( eg. 1 
row ) a single person could light up a whole orchard in a few minutes, 
either propane or fuel oil. I think that project only lasted a few 
years. pulsed 220 drifting avout an orchard was just too dangerous. 
Finally came the switch to sprinklers and orchard fans. 
and then grey smog  in the morning went away. No the old days were not 
necessarily the good old days.


Dave

On 4/10/22 8:31 AM, Mark Johnsen wrote:

That brings back memories.  The fun of being at Grandma and Grandpa's was
the Popular Mechanics and Popular Science magazines I could page thru when
visiting.

I remember all the pages in the back of the magazine where people were
trying to sell things, I always wanted a VW Bug replica car conversion to a
porsche or some old cool MB.  Those pages are like today's internet
advertisements, only the pages didn't do much tracking of your 'reading'
history.

Mark

On Sun, Apr 10, 2022 at 4:55 AM Mark  wrote:


Beat me to it.  I was just about to say the exact same thing.

What comes around goes around.

Mark

On 4/10/22 05:28, Gregg Eshelman via Emc-users wrote:

In other words the person who designed that created a pulse width

modulation motor controller without calling it that.


On Saturday, April 9, 2022, 08:18:17 PM MDT, John Dammeyer <

jo...@autoartisans.com> wrote:


Really nothing to do with LCNC or even automation.

I've been cleaning out old shelves and I have piles of Popular

Electronics Magazines.  This one from December 1965 (yes, almost 57 years
old) has an article on how to improve model trains so they start slowly or
crawl rather than lurching forward requiring backing off the speed control.

They call it pulse power.  Using only transistors and diodes the article

describes a method of creating narrow pulses superimposed on a varying DC
voltage.  One knob controls the width of the 12V pulses and the other the
amplitude of the DC mixed with the pulses.  The pulses are 60Hz.

Now we just buy stuff like that for way less than what the transistors

would cost.  Things have come a long way.

Just thought I'd share.
John


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[Emc-users] custom | stock bearing nut

[dave engvall]

Hi all,
I have a pair of ball screws: THK KX 71227 A
These are new but older and as far as I can tell not on the THK site.
They are threaded on one end to retain a bearing.
M15 x 0.8 or close. Does anyone know of a bearing nut that would fit or 
am I stuck with

having a pair custom made?
I've spent a fair amount of time searching the web but maybe (probably) 
someone else's  google foo is better than mine.

As always TIA

Dave


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Re: [Emc-users] Homebuilt encoder

[dave engvall]

Works fine here. If someone had not commented I'd wouldn't  of had a clue.

Dave

On 3/31/22 12:54 PM, Martin Dobbins wrote:

Perfect, thanks!

Martin


From: Lawrence Glaister

very strange... working fine here. maybe try the http version...
using firefox 98.0.2 (64-bit) here.


http://ve7it.cowlug.org/spindle-encoder.html

I would like to track down the issue, so please let me know if you find
its browser related or any other clues I will dive into the server
logs and see if they give any clues. See if multiple refreshes work...
maybe its related to server load???

cheers
Lawrence


On 2022-03-31 11:52, Martin Dobbins wrote:

Same here,

Martin


From: Mark Wendt

Link no worky.  Returns an error "The Request Entity is too Large".

Mark



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Re: [Emc-users] Homebuilt encoder

[dave engvall]

At high rpm a resolver may make more sense ... and more $$. Depends. ??

Dave

On 3/27/22 2:03 PM, ken.stra...@gmail.com wrote:

Gene, do you have a part number for your high RPM Omron encoder? Maybe I can
snag one...

-Original Message-
From: gene heskett 
Sent: March 27, 2022 4:49 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Homebuilt encoder

On Sunday, 27 March 2022 15:45:48 EDT ken.stra...@gmail.com wrote:

If you want spindle positioning (for more accurate probing of
alignment for tool changes for examples) you'll need the encoder to
follow the position at all speeds. Are there high RPM capable absolute
encoders at a reasonable price?

The one I have on the rear end of that 1hp motor, an Omron 1000 ppr, cost me
$21 on fleabay 6 years ago. Its a differential model I'm converting to ttl
in a pair of rs485 to ttl interfaces that cost about $2 each, driving a 5i25
card. NO optics in that path. Absolute it is not, but if the encoder tracks,
who cares.

Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis





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Re: [Emc-users] Because I can't seem to finish anything... Nebel lathe conversion.

[dave engvall]

It is my understanding that ball screws are case hardened so grind to 
get under the case and

then things get easy.
Interesting and good job on the ball nut. !!

In line with the nebel prize: the machine should be a very light grey 
and your hand should pass thru it easily.  ;-) Nebel = fog.


Dave

On 3/21/22 7:46 AM, gene heskett wrote:

On Monday, 21 March 2022 08:19:14 EDT Sam Sokolik wrote:

Dad ground the ball screw nut..   everything fits nicely under the
cross slide it seems..  Found a bit of aluminium to make a simple
bearing block for 2 angular contact bearings..

https://photos.app.goo.gl/NcW1fxrBGBgXH1SPA
https://photos.app.goo.gl/jWwKR5Fvz9ae4bbR7
https://photos.app.goo.gl/jWwKR5Fvz9ae4bbR7


Unforch Sam, no access


On Sun, Mar 20, 2022 at 5:56 PM gene heskett 

wrote:

On Sunday, 20 March 2022 18:07:01 EDT John Dammeyer wrote:

Gene,
The replacement ball bearing fan isn't on the bed fan duct but
cools
the top part of the hot end where the filament enters the PTFE
lined
feed pipe.

Ah, PTFE lined hot end. Needs tubing replaced as even at 200c nozzle
temps, the stuff eventually goes away or leaks badly. Feed it PETG at
240C, goes away in 2 days. All metal hot ends are better, titainium
heat breaks even better. Better yet I suspect is the copperhead
copper/ titainium combo but like the PCD nozzle, bring real money.


Problem solved which the new blower duct, now not aimed at the hot
end, did not completely fix.

should be aimed at or just below the nozzle tip.


Wrapped hot end block in insulating paper and Krylon tape.   Now
nice
flat curves and no drop in temperature even with 98% bed fan speed.

John


-Original Message-
From: gene heskett [mailto:ghesk...@shentel.net]
Sent: March-20-22 2:50 PM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Because I can't seem to finish
anything...
Nebel lathe conversion.>

On Sunday, 20 March 2022 16:46:17 EDT John Dammeyer wrote:

Story of my life.  Fan failed on 3D printer.  Repaired feed
tube
and
replaced with ball bearing fan I had from power supply
manufacturing
inventory.   Almost 1 week later still not working quite the
way it
was and the way I want. John

ball bearing fans start easier, leads to over cooling the early
layers. Change the min speed so its stopped for the 1st layer
like
it used to be at 25% power. Sleeve bearing fans often don't start
at
all till the mid 30% range.

Try zero for the first layer or even as high as the third layer
before
the fan actually starts. I have a ball bearing fan on my BIQU BX
and
it runs plenty fast enough at 30% of max in cura for PETG which
needs far less cooling than PLA. I don't mess with PLA at all,
too
brittle.

I've also put a diamonback .4mm PCD nozzle in mine so I can use
the
carbon fiber filled PETG but haven't yet seen the need for its
improved strength. I'm running the nozzle at 252C and the bed at
90C
and my printed air manifold is air tight. Bed adhesion is only a
problem getting stuff loose. Its almost too good. If the nozzle
is
slobbering, check how tight it is, then reduce the flow 2% at a
time
to stop the overflow, this PCD nozzle conducts heat into the
filament better than brass, melting it better which can increase
the
flow. At 245C the part will not be airtight if you need that. At
252C the part gets noticably glossier because its more liquid and
bonds well to the next layer down before it cools and solidify's.

Take care and stay well John. And my teeny version to be used as
the
B
axis driver on my 6040 mill, the one that costs around a tenner
to
make, seems to be pretty solid, got several hundred hours on it
now
but it probably going to get another 200 running a hard maple
stick
for a woodworkers leg vise screw. I've got to make an idler yet
to
tighten the belt as that is the only backlash it it.

Cheers, Gene Heskett.
--

"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."

-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law
respectable.>

  - Louis D. Brandeis

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Cheers, Gene Heskett.
--

"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."

-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law
respectable.>
  - Louis D. Brandeis

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.


Cheers, Gene Heskett.




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Re: [Emc-users] Because I can't seem to finish anything... Nebel lathe conversion.

[dave engvall]

A while back I swapped out my accurite glass scales on x and y (manual 
mill) for 5 um Chinese ones because my  DRO was going bad. The accurite 
ones are better but were not compatible with a Chinese DRO. Still very 
good to passable without adding the builtin comp. Fixes the problem of 
counting turns. ;-) And I might say adds confidence to the job. I 
actually did it because I wanted a check on the, still in progress, 
project of having stepper-servos on all three axes.

More later, maybe much later.

Dave

On 3/18/22 7:32 AM, Sam Sokolik wrote:

Thought about it...  :)

On Fri, Mar 18, 2022 at 4:50 AM andy pugh  wrote:


On Fri, 18 Mar 2022 at 03:11, Sam Sokolik  wrote:

https://www.youtube.com/watch?v=mes7pFZ90Fg

If you fitted linear scales you could potentially have manual rapids
by disengaging the half-nuts.



--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Graceful pi shutdown, power off

[dave engvall]

Those 'smart sockets' can be really handy. I use one to control the 
startup of my 3 phase rotary converter. That way I can be in the shop 
and only have the converter running when I need 3 phase. In the house is 
a manual lockout switch for times when I know I won't need 3 phase.


Dave

On 2/15/22 9:19 AM, Chris Albertson wrote:

How much power does your system use?  If it can be powered from a normal
120 volt AC  then you can buy a "Smart Outlet" that switches the 120V by
WiFi, cost about $10 or $15.  The Pi then can turn off or on any AC mains
powered device.  They sell these on Amazon or at Home Depot. You can
buy them in a plug-in device or as a powerstrip where each socket is
addressable.   There are quite a few of these on the market.

Here is what I have:
amazon.com/dp/B07B8W2KHZ


Place the script to turn the power on and off in  /etc/rc5.d and /etc/rc6.d
and then it is done as the normal part of booting and shutdown.

If you like the device you can likely find a use for half dozen of them
around the house, use them like light timers with software that runs a
schedule 24/7 or use them to control AC powered stuff from a phone app.




On Tue, Feb 15, 2022 at 6:28 AM Thaddeus Waldner  wrote:


On a small cnc machine run by a raspberry pi, I’d like to set up the main
power to accomplish the following:

1)pressing the power button/flipping the switch turns on the machine

2) pressing the off button, the pi should first perform a shutdown then
turn off the main power to all control power supplies.

3) shutting down the pi via the user interface turns off main power to all
control power supplies when finished.

I’m considering installing one of those powered mains disconnect switches,
the likes of what you find in office photocopiers and industrial cnc
machines.

Any ideas?



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Re: [Emc-users] need gcode maker

[dave engvall]

I typically have gone to West Marine for epoxy. 5:1 mix ratio with 
metered pumps. Good  idea about avoiding the glass expander/thickener 
micro bubbles. :-) Fast, med and slow catalyst available.


Dave

On 2/14/22 2:10 AM, Gregg Eshelman via Emc-users wrote:

Modern epoxies like the ones sold by Total Boat set up harder and don't yellow 
like the epoxies of the 1980's and earlier. An alternative to epoxies are the 
hard urethane resins, also typically made with UV protection.

Total Boat looks like it's the #1 brand of epoxy used by people making those 
"river" tables and mixing all kinds of weird stuff with epoxy to turn fancy 
bowls on wood lathes.


On Sunday, February 13, 2022, 06:16:31 PM MST, Chris Albertson 
 wrote:

It is not the epoxy that is so hard.  It is the filler they mix with the
epoxy.  Many times it is a kind of glass, not unlike what they use to make
sand paper.  Other times they mix finely ground bits of steel.

I used to use a brand of epoxy that sold bottles of pure resin and cans of
filler.  I could mix what I needed for the job.  Sometimes I'd use "micro
balloon" filler these are tiny hollow balls of glass.  A gallon tub of them
weights about as much as an empty tub.  Mixed to a thick paste, it cures to
a foam you can and with a sure-form rasp.  But if you mix the same resin
with chopped fiberglass or chopped kevlar fiber it is as hard as stone and
you'd need an angle grinder to smooth it down.  I was building small boats
and canoes.

Yes epoxy can be damaged by UV light.  If doing a gunstock, put 4 or 5
coats of exterior marine varnish over it.  The marine stuff has UV blockers
(sunscreen) in it.


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Re: [Emc-users] need gcode maker

[dave engvall]

With current technology wood glues ( epoxy ) are often stronger than the 
wood which allows one to machine short sections and glue them together 
for a composite piece that is as strong as a contiguous part.  I think 
Gene is talented enough to make a live axis for his lathe that would do 
a bang up job of making those threads. Going thru the pain to do that is 
left as an exercise for the local shop. ;-)  Nothing is impossible for 
the person that doesn't have to make it work.


Dave

On 2/13/22 10:32 AM, ken.stra...@gmail.com wrote:

Thread milling would be a good approach except that I doubt that Gene has 
18-inches of Z-clearance on his small mill to thread the length of his desired 
screw plus spindle clearance to mill to the table might be an issue.

-Original Message-
From: dave engvall 
Sent: February 13, 2022 1:20 PM
To: emc-users@lists.sourceforge.net
Subject: Re: [Emc-users] need gcode maker

Other options for buttress. DIN |  ANSI .. Either grind a tool out of M2 or 
equivalent or go shopping for inserts on the web surplus sites. They won't be 
cheap but a bit less hassle.
Single point thread mill??
Lathe sound easier than milling it.

Dave

On 2/13/22 9:37 AM, ken.stra...@gmail.com wrote:

Alternatively one can tilt the stock rather than the head which I
believe is Gene's plan.

-Original Message-
From: Robin Szemeti via Emc-users 
Sent: February 13, 2022 12:26 PM
To: Enhanced Machine Controller (EMC)

Cc: Robin Szemeti 
Subject: Re: [Emc-users] need gcode maker

If you can tilt the head at an angle, then something as simple as "G1
X300.00 B30.00" will do it, depending on how you have configured the B axis.
If you can't  tilt the head, no amount of GCODE will help you.

I'd just do it on the lathe ...

On Sun, 13 Feb 2022 at 16:54, gene heskett  wrote:


Greetings all;

I have composed a simple butress thread in OpenSCAD, which can save
many formats besides the .stl's I feed cura with. Those choices are
shown in this list:
STL
OFF
WRL
AMF
3MF
DXF
SVG
CSG
PDF
image (png)

The latter being what you see in the attached png images.

What is out there that can make gcode out of one of those formats,
assuming I can do some creative editing to make the bolt code carve
an 18" bolt from a hard maple 2x2 being spun by a B axis as Y slowly
advances with aux tables to make the Y axis long enough on both ends
on my 6040 mill, and I till use a 60 degree engraving mill in it with
a 30 degree wedge under the motor mount to tip it to make the 0
degree load face of the thread with the side of the tool's V. I
intend to make the wedge as a hinge if I can print it rigid enough.
And PETG seems like it could be the Right Stuff.

The target of all this tom-foolery is a wood workbench vise screw.
The 2nd half nut is about half done on my BIQU HX printer as I send this.
So its beginning to look do-able.

I faintly recall that inkscape had a gcode generator plugin at one
time, does anyone have a clue how well it works or if it even exists

today?

Synaptic does not look promising but I installed inscape and friends
anyway, and of coarse pycam, and I just found dxf2gcode, so that got
installed.

Does anyone else have a better idea?

Thanks All;
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
   soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
   - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>
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Re: [Emc-users] need gcode maker

[dave engvall]

Other options for buttress. DIN |  ANSI .. Either grind a tool out of M2 
or equivalent or go shopping for inserts on the web surplus sites. They 
won't be cheap but a bit less hassle.

Single point thread mill??
Lathe sound easier than milling it.

Dave

On 2/13/22 9:37 AM, ken.stra...@gmail.com wrote:

Alternatively one can tilt the stock rather than the head which I believe is
Gene's plan.

-Original Message-
From: Robin Szemeti via Emc-users 
Sent: February 13, 2022 12:26 PM
To: Enhanced Machine Controller (EMC) 
Cc: Robin Szemeti 
Subject: Re: [Emc-users] need gcode maker

If you can tilt the head at an angle, then something as simple as "G1
X300.00 B30.00" will do it, depending on how you have configured the B axis.
If you can't  tilt the head, no amount of GCODE will help you.

I'd just do it on the lathe ...

On Sun, 13 Feb 2022 at 16:54, gene heskett  wrote:


Greetings all;

I have composed a simple butress thread in OpenSCAD, which can save
many formats besides the .stl's I feed cura with. Those choices are
shown in this list:
STL
OFF
WRL
AMF
3MF
DXF
SVG
CSG
PDF
image (png)

The latter being what you see in the attached png images.

What is out there that can make gcode out of one of those formats,
assuming I can do some creative editing to make the bolt code carve an
18" bolt from a hard maple 2x2 being spun by a B axis as Y slowly
advances with aux tables to make the Y axis long enough on both ends
on my 6040 mill, and I till use a 60 degree engraving mill in it with
a 30 degree wedge under the motor mount to tip it to make the 0 degree
load face of the thread with the side of the tool's V. I intend to
make the wedge as a hinge if I can print it rigid enough. And PETG
seems like it could be the Right Stuff.

The target of all this tom-foolery is a wood workbench vise screw. The
2nd half nut is about half done on my BIQU HX printer as I send this.
So its beginning to look do-able.

I faintly recall that inkscape had a gcode generator plugin at one
time, does anyone have a clue how well it works or if it even exists

today?

Synaptic does not look promising but I installed inscape and friends
anyway, and of coarse pycam, and I just found dxf2gcode, so that got
installed.

Does anyone else have a better idea?

Thanks All;
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page 
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Re: [Emc-users] IJK vs R

[dave engvall]

Clearly, I've not been reading in the right place. That 7%  is new info 
for me. I assume that the 7% is a worst case but I have no idea how 
someone came up with that figure. I that magnitude of error is common it 
is a serious fault but I don't  think I've ever seen real errors but 
then how many  of us have good enough instrumentation to check that. So 
much of what I do are perimeters of features that don't have to exactly 
match  anything else so obviously we get away with it. In reality I 
suppose that if you need  it nice and round you interp to close and then 
use a boring head but that does not solve some conditions. Can't win 
them all.


Dave

On 2/9/22 4:17 PM, andy pugh wrote:

On Wed, 9 Feb 2022 at 19:30, dave engvall  wrote:

Hi,
It would appear that the 'easy' way to compare the two methods would be
to  use  sim or usrspace. That would get it plotted but I doubt the
differences, unless gross, would be easily detectable on a plot.

Thde docs state that a 7% difference was seen, but with some brief
experimentation I can't see it:

F1000
G0 X0 Y0
G2 X10 Y0.1 R5.00025
G0 X0 Y0
G2 X10 Y0.1 I5.0 J0.05
M2





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[Emc-users] IJK vs R

[dave engvall]

Hi,
It would appear that the 'easy' way to compare the two methods would be 
to  use  sim or usrspace. That would get it plotted but I doubt the 
differences, unless gross, would be easily detectable on a plot. I've 
forgotten, if indeed I ever knew how to list output from something that 
calculates points along the way. A gentle or not so gentle nudge would 
be appreciated.


Dave

stepper  should work also since it really doesn't know if something is 
connected ...



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Re: [Emc-users] Trouble with arc error

[dave engvall]

Hi,
I've read the assertion many times that ijk is better than radius and 
always assumed it to be correct; but by how much.
Few of us run machines and are 'new' tigjht ;-) Maybe  I've not looked 
in the right place(s)
for an analysis or for demonstrated interp of circles with some kind of 
error band. Any proof and or experimental evidence?

Just poking the bear. ;-).

Dave

On 2/7/22 1:01 PM, andrew beck wrote:

One option is set your post processor to post radius not ikj values.


That helped me once.

They are much more forgiving

On Tue, 8 Feb 2022, 09:48 Stuart Stevenson,  wrote:


Something is fishy between the Y values.
You have Y4. in the first list and Y0. in the full listing.

On Mon, Feb 7, 2022 at 2:39 PM Stuart Stevenson  wrote:


I see it in your gcode file listing

On Mon, Feb 7, 2022 at 2:39 PM Stuart Stevenson 

wrote:

Where is the decimal point in the X value of "End=(X1, Y0.8964)"?
I would say it is X1. and expect this is a typo when you entered

this

in the email.


On Sun, Feb 6, 2022 at 11:12 PM Andy Howell  wrote:


We had been cutting with the same gcode when suddenly it came up with

an

error:

Radius to end of are differs from radius to start:

  Start=(X1.4208,Y4.8728)

  Center=(X1.4208, Y4.8964)

  End=(X1, Y0.8964)

  r1=0.0236

  r2=4.0001

Its got to some config issue. The same file runs in the simulator just
fine. That r2=4 is curious. We are cutting in a jig using fixture G55.
We had touched off the Y by 4 inches to run the file again. That worked
fine. We more the Y back 4 inches and touched off again to set the G55
back to its actual 0,0 origin. When we ran the time, we started getting
this error.

This is the code in question. Its complaining about line N70.

%
(TEST PIECE 4IN)
(MY PROGRAM COMMENT)
(T1  D=0.2362 CR=0. - ZMIN=-0.11 - FLAT END MILL)
N10 G90 G94 G17 G91.1
N15 G20
N20 G53 G0 Z0.
(BORE6)
N25 T1 M6
N30 S18000 M3
N35 G55
N40 G0 X1.3853 Y0.8728
N45 G43 Z0.6 H1
N50 G0 Z0.08
N55 G1 Z0.0236 F20.
N60 G18 G2 X1.409 Z0. I0.0236 K0.
N65 G1 X1.4208
N70 G17 G3 X1. Y0.8964 I0. J0.0236

Any ideas about what is wrong? We are running LinuxCNC 2.7.15.

Thanks.



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reading, and cease and desist from saving or opening my private
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Thank you for honoring my wish.



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Re: [Emc-users] What Would You Suggest?

[dave engvall]

Hi,
I seem to remember a crank as in crankshaft lashup to drive the table. 
Personally I think the hydraulic setup is better but harder to achieve. 
The free lunch is hard to find.

Dave

On 2/4/22 9:11 AM, John Dammeyer wrote:



From: Kenneth Lerman [mailto:ler...@se-ltd.com]
The longitudinal travel is just over a foot, and it takes about 3-1/2 turns
of the crank to go that distance. I'm thinking around  a second per turn
would be about the maximum. So, that's 60 RPM. I'm thinking of a 1:6 ratio
on the timing belt pulleys, so that's 360 RPM at the stepper which is
pretty slow. A full stepping rate would be 200 * 360/60 => 200 * 6 which is
only 1200 steps per second.

You won't want to run full step.  A minimum should be 8 micro-steps/step to 
avoid resonance and loss of position or lockup.   I'd measure the torque 
required to move the table by attaching a lever to the hand wheel that is say 
1' long.  Set it horizontal and start hanging weight onto the end to get ft-lbs 
or ft-in until it turns. That's the torque required to overcome static 
friction.  Double that to choose your motor.

Say that is 1 ft-lb or 192 oz-in.If you choose 3:1 for your reduction ratio 
you get 600 oz-in.  Look at the motor torque curve (they are all different and 
if the supplier can't give you that buy one somewhere else) and see where the 
torque drops below 400 oz-in.  Say that's 180 RPM.  That's 3 RPS which 
multiplied by 2000 steps per rev for micro-stepping is 6000 steps/second which 
achieves your 1 RPS on the handle.

Or if you find it's 2 ft-lb or 400 oz-in choose a much larger motor like 1200 
oz-in
http://www.automationtechnologiesinc.com/download/9259/
Notice the curve at 3000 half steps per second is about 3.2NM.  That's 12,000 
steps per second (7.5RPS)  with 8 micro-steps per step well within the reach of 
even a parallel port controller and 450 oz-in.  That's well above the 1 RPS you 
need and even just 3:1 still gives you 1600 oz-in.

My two cents...
John Dammeyer

An alternative would be to provide more gearing, but I don't think it's
practical to get more than about a six to one ratio in a single belt
reduction and I'd like to avoid mechanical complexity if I can.

Thoughts?

Ken

Kenneth Lerman
55 Main Street
Newtown, CT 06470



On Fri, Feb 4, 2022 at 7:13 AM Chris Albertson 
wrote:


If looking for lowest cost solution you can us the old "Atom" computer to
control the grinder as long as you do not  need to run the mill and
grider at the same time.  Get an Eiternet interface Mesa card for the new
machine,  You need two config files, just load the one for the mill or the
one for the grinder.

Then someday you buy a second computer you only have to move the Ethernet
cable over.   The best option is a newer version of the Atom.  They seem to
sell for just under $200.   Finally Newegg.com always has many used oe
refurb PCs   Used PCs sourced locally can be a cheap as "free"

But 9ld PCs tend to burn up a lot of power.  I am trying to get mone to do
"wake on LAN" so it can not use power until I need to log onto it

On Thu, Feb 3, 2022 at 6:52 PM Kenneth Lerman  wrote:


I'm considering converting a surface grinder to CNC. To start, I'll
probably just convert the longitudinal and transverse axes.

I'll go with steppers for this -- I'm thinking NEMA-42 motors.

My current Bridgeport clone uses servos and Jon Elson's hardware on a
little Intel Atom Box. I'm thinking of using a Rpi for this. It will

need a

minimal display/control panel when completed, but initially will need a
display with touchscreen or mouse and possibly a keyboard. In the long

run,

some buttons. and perhaps an mpg might be useful.

I'd like to use a raw Rpi without adding special hardware directly. That
probably means using a USB or ethernet interface to control the steppers.
I'm thinking of using Mesa hardware.

Can someone suggest the most cost effective way to do this? (Although I
have to admit, that after buying the timing belts and pulleys, the
steppers, power supply, stepper drivers, ..., it's too late to be really
cost effective.). And the surface grinder only cost me $300.

Thanks,
Ken



Kenneth Lerman
55 Main Street
Newtown, CT 06470

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Re: [Emc-users] Mini-itx 64bit mother board with parallel port

[dave engvall]

Yep! Brain dead, missed those.

Dave

On 2/3/22 8:33 AM, andy pugh wrote:

On Thu, 3 Feb 2022 at 15:28, dave engvall  wrote:


At first glance it looks pretty good but lacks pci slots unless my eyes
have fully given out.
Ditto on disk interface.

Assuming you mean  https://www.onlogic.com/pd14ri/
It has 2 x SATA connectors and 1 x PCIe (so a Mesa 6i25 would fit)





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Re: [Emc-users] Mini-itx 64bit mother board with parallel port

[dave engvall]

Greetings:
At first glance it looks pretty good but lacks pci slots unless my eyes 
have fully given out.
Ditto on disk interface. So unless the pport has a good EPP and 
therefore useful for 7i43 | USC | ppmc it is not a good deal. Just my 
tuppence.


Dave

On 2/2/22 10:43 PM, Chris Albertson wrote:

I just looked around.   There seem to be many at this price point of just
under $200 that all have 6 Watt CPUs in them and several have parallel
ports. Anyways, sub-$20 Intell machines for industrial use seem to by
plentiful.  Much better then a Raspberry Pi for not much more

However if I were setting up a new system I'd not want a parallel port.
Ethernet seems to be better and many of these little mini-ITX boards have
two Ethernet ports on them, as I assume they are designed to be file
servers.

In actually I just bought one, kind of.  It is a Synology NAS with one of
these low-power quad core CPUs inside.  It does RAID and will hold all my
files with a 10 Watt CPU.  (I know it is nothing to to with LCNC, except
file storage.  I'm looking to consolidate storage and backup

On Wed, Feb 2, 2022 at 6:44 PM gene heskett  wrote:


On Wednesday, February 2, 2022 9:08:01 PM EST Chris Albertson wrote:

I followed that link.Wow, that is a good deal.  Especially when you
look at the power supply.   It uses a 12 volt barrel jack and a large
size wall-wort.   The CPU burns all of 6 Watts.It could run on
battery power.

It is good to look for low-power PCs if they are going to run all day,
every day.  The cost of power really adds up.  The bix Xeon powered HP
I use for development work costs maybe 12 cents an hour.  That is
about $400 at the end of the year.

The machine I use to power LCNC and my 3D printer is an Intel i5 and I
could justify downgrading it based on power-saving along.   I had not
realized there was such things at 6 Watt quad-cord Intel CPUs.

On Wed, Feb 2, 2022 at 3:35 PM Andy Howell  wrote:

On 2/2/22 16:31, gene heskett wrote:

On Wednesday, February 2, 2022 4:42:22 PM EST Andy Howell wrote:

I was hoping to update to a recent Debian and LinuxCNC version.
However, I have a 32bit motherboard. This is for our school, so
I'm
trying to contain cost by just replacing the motherboard.

Any suggestions for a 64bit mini-itx motherboard?

Most any NEW mobo today will need a new cpu too since the sockets
are
changed and probably won't take your old memory for the same
reason.

ATM I'm running a normal sized Asus Z370-AII with the cheapest 6
core i5 on it and I'm as happy as I can be. Asus makes decent
stuff. Draws about 140 watts less than the phenom it replaced.

And stay away from OLOy memory, I had a failure and they needed
more data than I had to replace it, so I had to buy a different
brand to replace it. That's BS, so be sure, get it in writing,
that you can get in warranty replacements by simply shipping the
bad one back with a photocopy of the bill of sale. If they won't
do that, go down the list to the next vendor.

Gene,

It looks like most of the Mini ITX boards have the cpu soldered in. I
don't imagine I'd need a lot of memory. 2GB maybe?

Looks like this will do the trick. $200 with 2GB of memory.

https://www.onlogic.com/pd14ri/


There is however, one detail that would discourage me, its already EOL,
came out in q4-15, lifespan 4 years, so its approaching 2 years since
last shipped.

Where is the support, I never got that page to load.

Thanks,

Andy






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Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page 





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Re: [Emc-users] motherboard that plays well with 7i43

[dave engvall]

My thinking is that the 7i43 is best used for rt tasks with an EPP port, 
hence the problem. I should have been more explicit.   The plan is mb -> 
7i43 -> 7i42 for stepper-servos.

Dave

On 1/28/22 11:17 AM, Chris Albertson wrote:

On Fri, Jan 28, 2022 at 10:18 AM dave engvall  wrote:


hi,
I'm looking for users that are actually using a motherboard with a 7i43
and can recommend candidate boards from experience. Thanks in advance.


A related question I have is "Does choice of mainboard matter?"  I'd guess
if you are using the USB interface it wouldn't.

I was thinking of using the Ethernet interface Mesa board but then read it
needs a dedicated Ethernet port in the host PC.  This means buying,
installing, and configuring an Ethernet card. The PC or any PC today
already has half a dozen USB ports.  Even a Raspberry Pi has 4 USB ports
and might work well for this.

But my question is not about using a specific PC, but rather if it matters.




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[Emc-users] motherboard that plays well with 7i43

[dave engvall]

hi,
I'm looking for users that are actually using a motherboard with a 7i43 
and can recommend candidate boards from experience. Thanks in advance.


Dave


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Re: [Emc-users] miniature taper-lock type pulleys

[dave engvall]

On 1/27/22 1:47 AM, andy pugh wrote:

On Thu, 27 Jan 2022 at 04:49, Ralph Stirling
 wrote:


  I got to wondering if it
would be possible to make a miniature taper lock
type bushing and pulley to clamp onto a stepper
shaft.  Anybody ever seen anything like that?

I have designed and used a few options.

Trantorque are great, but do require a relatively large pulley bore.
And they are not the cheapest.

Some alternatives that I have used:

Very thin taper-loc
https://bodgesoc.blogspot.com/2017/01/gears.html

Taper-loc / Trantorque hybrid
https://photos.app.goo.gl/8NTXSFrFtBfRQ2Ds7


I use the mini   5/8" fits the SEM servo motors I use.
Dave


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Re: [Emc-users] miniature taper-lock type pulleys

[dave engvall]

I assume everyone knows about these.
https://www.fennerdrives.com/trantorque/
Not cheap but tend to work.

Dave


On 1/26/22 8:30 PM, Ralph Stirling wrote:

I had some problems today with a small XL timing
pulley slipping on a NEMA17 stepper shaft due to
the set screw loosening after running for long
periods (multiple days).  I drilled and tapped a
second set screw hole, and I can probably apply
some thread locker, but I got to wondering if it
would be possible to make a miniature taper lock
type bushing and pulley to clamp onto a stepper
shaft.  Anybody ever seen anything like that?

The original taper lock system has a split bushing
with an 8 degree taper against the pulley.  They
also have a clever set screw arrangement to tighten
the pieces together and to jack them apart when
removing.  If you haven't used them before, a video
is the best way to understand them:
https://www.youtube.com/watch?v=-3K_vf_7fhM

I like to 3d print my timing pulley perimeters, but
a metal hub is nice (as has been discussed on here
in the past).  I'm pondering how I could make hybrid
pulleys with a taper locking hub.  Threading the holes
in the plastic pulley wouldn't work so well.  Perhaps
some threaded metal insert can be incorporated from
the back side.

Enough of my musings.  Looking forward to hearing
other ideas and suggestions.

-- Ralph

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Re: [Emc-users] rotary table re-engineeering

[dave engvall]

Known good part obscures the problem of shrinkage unless you want them 
to take your known good and scale it for shrinkage which they will do at 
$$/hr. ;-)
Working from their shrink % will allow you to do the sizing and that 
make it simple for them.
A foundry 100 mi or so from me and out in the boonies was using house 
insulation foam for patterns but that generated a lot of plain carbon 
smoke so I don't know if they do that anymore.

Good luck with your part however you do it.

Dave

On 1/23/22 10:56 AM, Chris Albertson wrote:

What you give a foundry is typically the part you want, a pattern.  They
can advise on the limits of what they can do.  For example there is a
minimum and maxim thickness and overall size.

They can also tell you how much the iron will shrink so you can adjust the
pattern

Then for you own good you would want to make the pattern so as to minimize
the amount of machine work.  This also saves you money as you pay the
foundry by the pound.   So make the parrn have all the curves and shape you
need.

Wrapping is another issue.  if you make it too thin or thick the result
will not match the pattern.

Tranditionally, patterns where made of wood or maybe wood with bondo over
it and sanded and finished sooth.  But today you would 3D print the pattern
and give them a plastic copy of the part you want.  They pack it in sand
and make a mold from your pattern.

Some can do a process that is like "lost wax" so then you print using a
kind of plastic that the melted metal burns up

But this is for a "*mini*-mill"  you do NOT need cast iron parts.  The
cutting force is very small.  Why not make your adaptor out of plastic?
Platic seems like the wrong material because "real mills" are made of
steel.   I have a CNC converted Mini mill and the conversion parts are
printed plastic.It you design, knowing the strength of that material
you can do well.  I can not measure flex with a dial indcator
Plastic is like designing a part with glass.  It is very strong and rigid
until it shatters.  But look at the size of the spindle motor and drive
gears on a mini mill.   You would shear the teeth off the drive gears
before generating enough force to break a plastic adaptor shim.

In any case, then after AFTER you know the plastic part works, then you
give the foundry the known-to-work part to use as a pattern and they make
you one in metal.

I've dealt with some manufacturers and while you used to have to ship a
pattern, now days you can email them the design file and they can print the
pattern and do the design check that looks for violation of thier min and
max thickness.

There are also places that can do a 3D print in metals like aluminum of
even stainless steel.  But this is not yet cheap.

On Sat, Jan 22, 2022 at 6:26 PM fxkl47BF--- via Emc-users <
emc-users@lists.sourceforge.net> wrote:


Yes, if you are near Windy Hill, then I understand that they do a lot
of one-offs for vehicle restorers etc.

It's certainly worth considering.

OK
So from the photos in the ad what would I want to have made?
A big rectangle?
The only "true" surfaces on the back are the dovetails.
I think that's a bit of a wimpy mount.
If I disassemble it I can tell if the unfinished surfaces beside the
dovetails are thick enough to drill for additional supports.
Or is that a lot of overkill.
Just attach to the dovetails and be done with it.
I have a 3D printer.
This is go'n to to be fun :)




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Re: [Emc-users] motor coolant for water cooled spindles.

[dave engvall]

Cu inhibits algae and should do a decent job on most bacteria. So a bit 
of Cu sulfate.
Zn chloride and or ferrous chloride inhibits moss but the ferrous 
oxidizes to ferric and stains
siding/concrete so use the chloride. In a pinch just use a bit of 
Clorox; even peroxide should do the job.
If you can keep the mist away from your lungs you might try isopropyl 
alcohol.

HTH

Dave

On 1/16/22 1:42 PM, gene heskett wrote:

On Sunday, January 16, 2022 4:01:01 PM EST andrew beck wrote:

Why not just engine coolant

Is that what you are using?

I first started out with rv antifreeze, but it spoiled and jelled solid
couldn't even bore it out or blow it with 125 psi of air, plugging up the
first spindle motor in about 90 days, and If this $200 4 bearing motor is
plugged, I'll be looking for an air cooled version, 2 motors in 2 years
is not acceptable.

This was distilled water with about 2% water wetter & enough lysol
bathroom spray, 6 or so oz in 4 gallons to keep it sterile, I thought...
This is not a sealed system running at 250F so its not self sterilizing
like an auto system is. Its a sorta clear plastic document storage box
with a buckle down lid, holds about 5 gallons, is vermin & insect tight,
but not air tight.

Thanks Andrew.


On Mon, 17 Jan 2022, 09:37 gene heskett,  wrote:

I just fired up the 6040 to make a pocket for a 3mm sq nut. Noted
that
the coolant tank was down about an inch from evaporation, but hand
hand on the tank could feel the pump buzzing so I assumed it was
working. Its an 80 gallon an hour submersible, probably for
aquariums and such. So I measure the nut to see how big a "pocket"
to make to hold the nut.

About 90% done with that, I noted an air bubble in the hoses to the
top of the motor was still there, feel the motor and it is pretty
warm, check the tank, cold. Lift the lid and find about 1/8" of
dirty grey mold sealing the top. So I'm back to trying to clean it
out so I put half a cup of lysol bathroom spray in it. But haven't
disconnected it so I can dump the tank in the back yard. Yet.

Obviously the modern lysol isn't the magic twanger to keep it sweet.
So what do you folks use to keep a closed system sterile,
non-corrosive and functional?


Cheers, Gene Heskett.




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Re: [Emc-users] Very good software backlash control demo.

[dave engvall]

Hi,
I ran across an article by one of the servo drive firms that said the 
using two sensors/axis improved motion. I think they used a resolver on 
the drive and an encoder on the ball screw. While this improves motion 
that assumes you have very good ball screws. I think that a better 
approach would be to use glass scales and  then another sensor on the 
ball screw or drive. Right now I have a mill with glass scales on X and 
Y with Z being considered. Planned is implementation of stepper-servos 
like Gene's setup. First iteration will be stepper-servos plus a DRO 
simply to tell me how bad things are.
BTW -- on X using the hand wheel vis a vis an accu-rite 5 um glass scale 
was dead on moving X  in the positive direction  I won't admit how bad 
it is on reversal. ;-) Y is damaged but still pretty good going positive 
but really bad in Y neg. No scale on Z so no estimate but not perfect. 
The X  does have a 40 K count/inch in quadrature encoder on it.
Note: Chinese glass scales are now mounted on X and Y since the 
Accu-rite scales do not play well with the Chinese DRO.


Cheers,
Dave



On 1/3/22 6:58 PM, Sam Sokolik wrote:

This has been done at a bigger scale...  (2 feedback loops)

https://web.archive.org/web/20160222165548/http://jmkasunich.com/cgi-bin/blosxom/shoptask/wichita-trip-02-20-08.html

http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Combining_Two_Feedback_Devices_On_One_Axis

On Mon, Jan 3, 2022, 8:42 PM Chris Albertson 
wrote:


CNC is about precision motion control.   Here is a new idea where this
builder gets 0.05mm accuracy but uses hobby level R/C servo  Not only that,
but he connects three of these in series, one to the next to the next so
all the backlashes and poor tolerances add together.  Then he uses this to
do precise motion.  He loads a mechanical pencil with this chain of cheap
parts.

What does this means for LCNC?  It means that someone has found a software
solution to backlash.   What he does is place a quadrature encoder on both
the motor and the output shaft.The difference in encoder reading is an
exact measure of mechanical backlash and effective gear ratio.He can
measure the backlash under different conditions and store the
measurements.  Then he places a cascaded PID controller and Kalman filter
over this hardware.

Technically the problem with backlash control via software is the delay
from input to output pays poorly with the PID algorithm.  He applies a
predictive model.

Checkup this video.  It is unimpressive if you have a  $100,000 CNC milling
machine, but he is using a linked chain of hobby servos.  The novel idea is
his software.   It is on github, you can read it.
https://youtu.be/gq-P39rfRqU

He explains it  here.   Notice in the video he shows the backlash.  The
gear-slop is at the 1/4 inch level but using his software backlash
correction you can see the results in the dial indicator is about 0.05mm
(or about 0.002 in American units)  Not bad given the truly horrible
mechanics.
https://youtu.be/SioCwvR_PYY

Why do I care?   I have a robot-dog leg here on my workbench using hobby
servos, let's say performance could be improved.   But the anti-lash
technique might be used on a real milling machine. Maybe one of the
experts here could look and see if it could be applied?I will use parts
of his idea on my dog-bot.

--

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Choice of CNC conversions

[dave engvall]

I'd be lost w/o a command line editor. vi may be vile but vim can be 
surprising useful. My feeble brain still can't get configurations that 
work with a gui type  configure.  I'll gladly take a framework and 
modifiy it to suit my needs. Wish list: smoother motion probably via 
sine wave, moderate look a head and a screaming fast rt in a dedicated 
rt chip. Properly done the motion module doesn't change much but a lot 
of task stuff wrapped around it does and that allow improvements as the 
focus of the programmers changes. Just my tuppence devalued by inflation.


Dave


On 12/25/21 1:40 AM, gene heskett wrote:

On Friday, December 24, 2021 6:47:33 PM EST John Dammeyer wrote:

I think we perhaps need to take a step back before this turns into a series
of unworkable positions.

[...]

The basic setup screens for LinuxCNC for either parallel port or Peter's
MESA stuff is amazing and simple until you need to step outside the box.
And I think, if I were to summarize this I'd say software needs to be
designed so the command line editor is never ever used.  Those two sets of
config screen sets are what have allowed most people to set up LinuxCNC.
Take those away, tell them they have to write the HAL and INI file from
scratch and watch them run, quickly, to alternate systems.

What am I?  Cat food? John, that box your are complaining about is one heck of
a big box. I might run  the config ONCE when bringing a new machine to life,
from then on anything I do to that machine is done with geany, the text
editor.  The ONLY problem I've had is a reticence on the part of the
developers to add a pin or 9 to allow me to fully use a feature I built into
the pi controller on that Sheldon, in a fool proof 100% automatic way.

For instance, I put a pair of $20 mpja encoder dials, 100 ppr quadrature
output gizmos, so I can drive that Sheldon by hand just as if it still had
hand cranks. And they are many many times more convenient to setup a touch off
point than any keyboard or mouse driven method, unlike the keyboard or mice
they seem to talk directly to the hardware, with no lags like the keyboard or
mouse imposes on the accuracy as I can directly dial up a touchoff to within .
0001" or .001mm in metric mode. The machine is not that accurate but the
electronics is.

But one huge usability problem. Using the mouse or keyboard the active
touchoff gets automaticly applied to the last axis you moved. But there were
NO input pins to effect that from my dials. I had the signals available, but
it took me 3 years of intermittent fussing about it because when I'm doing
touchoff's that way, I had to hunt up the mouse, find that teeny little button
in the gui, and manually change it to the axis I ws abut to touch off. If my
touch off was applied to he wrong axis I broke tooling and muttered a lot. And
started all over with the setup. Old habits die, or kill you. I was given the
pins a couple months ago and its many times more useful now, no more messed up
touchoffs. There is a slight lag though, it seems to be activated on the
falling edge of my signal. I can speed that up, just haven't found my round
tuit.

The one size fits all approach you are touting as superior is not, its a very
small box limiting what you can do.

Merry Christmas to all.

Enough rambling for now.
John

  I agree

Cheers, Gene Heskett.




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Re: [Emc-users] Complex 6 axis robot arm.

[dave engvall]

I must say John that you are much more patient than I. As long as the 
parts will take the heat warming helps drive the epoxy cure. Roughly 10 
degrees C doubles the reaction rate. 175 F or 80 C is a good place to 
start. Assuming RT is 20 then 80-20 = 60 or 2^6 X. Naturally one may 
have to back off the temp for wimpy thermoplastics. ;-)


Dave

On 12/23/21 9:12 PM, John Dammeyer wrote:

I bought one of these well over 30 years ago.
http://www.autoartisans.com/armatron/SuperArmatron.jpg
  
My sons played with it until either they were bored or it stopped working.  It went back in the box and they never told me the motor no longer ran.
  
I ended up taking it apart and disassembling the small 3V DC motor.  Bend clips back, pull off plastic brush assembly.  Black greasy gunk all over the armature and brushes.  Once cleaned up and put back together the motor ran but two of the joints were problematic.  I really didn't want to take apart the arm but I could see a shaft turning but the gear not.
  
When I did it burst apart and gears and gears mounted on shafts were everywhere.   Took a while to figure it out what went where.  Now I've used the Dremel to carve some grooves into the shafts and small vise on mill to drill 1.15mm holes into the body of the nylon gears which, I'm guessing due to age, had cracked.  Almost looks like the gears were molded onto the shafts but no splines.
  
http://www.autoartisans.com/armatron/ArmDisassembled.jpg
  
Anyway, a bit of 60 minute epoxy and now I'll have to wait 12 hours for it to set good and hard and then the adventure of trying to put it all back together.  I know where it all goes now.
  
All mechanical, one motor turns continuously, the joysticks engage six different gears to create the joint motion.  The complexity reminds me of IBM Selectric typewriters I repaired as an IBM OPCE so many decades ago.
  
Now it's all done with computers.  I'm not sure there are even people around who could design something like this that is fully mechanical.
  
John Dammeyer


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Re: [Emc-users] Harmonic Drive

[dave engvall]

Soaking the plaster of paris encased part in sodium bicarb in water 
should dissolve the POP. Use as much bicarb as the weight of the plaster 
of paris. I've  not tried this so YMMV. ;-)


Dave

On 12/21/21 1:34 AM, Gregg Eshelman via Emc-users wrote:

One method of strengthening 3D printed plastic is to pack the item very firmly 
in very finely ground salt then heat it just the point where the plastic begins 
to melt. The firm salt keeps the size and shape and the plastic layers melt 
together more. It only work on parts with 100% infill. Can also use plaster but 
it's a PITA to get off the parts. 
https://www.youtube.com/results?search_query=3d+printing+salt

On Monday, December 20, 2021, 02:59:38 PM MST, Chris Albertson 
 wrote:
  
  Is it possible to post process a thermal plastic gear?  Lets say you took

a high-precision metal gear and heated it to 180C and the rolled it over
the printed gear with the correct center to center distance.  You would
need to build a test fixture to do this but might be worth it.

lately I've been experimenting with brass thread inserts.  I have 1/2
dozen different types and printed test blocks with different hole diameters
and I've tried the soldering iron at different temperatures.  The best
results are really good with the M3 size screw failing before the nut.
  The worst case is they just pull out easily with pliers.

The hard part seems to be repeatability and if the hole is parallel or at
right angles to the layers. Printer setting and part design seems to matter
a lot also.    I've got a walking-dog type robot and I need to convert it
all over to threaded inserts, about 80 places.  I find it helps to think if
each holes gets larger or smaller then design when it is printed. and this
depends on ho the hole is connected to the rest of the part.  By walls or
sheets or infill..  Engineering is fun...
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Re: [Emc-users] ER32 collet chuck

[dave engvall]

Apparently standard grade collets are grade A , AA collets are 
concentric to 5 um.


https://www.parlec.com/Products/Tool-Holding/ER-Collet-Chucks/Collets/5-Micron-(AA)/Inch-(1)

Dave

On 12/7/21 4:16 PM, John Dammeyer wrote:

Does anyone know the difference between the non AA and AA collets?

  
  

-Original Message-
From: ken.stra...@gmail.com [mailto:ken.stra...@gmail.com]
Sent: December-07-21 3:24 PM
To: 'Enhanced Machine Controller (EMC)'
Subject: Re: [Emc-users] ER32 collet chuck

I assume that you meant "ER40". I use one of these on my Myford lathe (not 
CNC!):
  

 
https://www.arceurotrade.co.uk/Catalogue/Collets/ER-Lathe-Collet-Chucks/ER40-Lathe-Collet-Chucks

There are many other vendors charging more and less. Searching eBay for "lathe 
collet chuck" will get dozens of hits such as
   https://www.ebay.ca/itm/184103307906.

-Original Message-
From: Gene Heskett <  ghesk...@shentel.net>
Sent: December 7, 2021 5:52 PM
To:   emc-users@lists.sourceforge.net
Subject: Re: [Emc-users] ER32 collet chuck

On Tue, 7 Dec, 2021 at 5:39 PM, John Dammeyer <  
jo...@autoartisans.com> wrote:


To: enhanced machine controller (emc)
I'm thinking of ordering one of these for my 4th axis so that I can finally get 
LCNC to do more than just demonstrate that I can rotate
it under computer control.  It appears to fit the same registration as the 
smaller 3 jaw chucks so a face plate that can register it or the
chucks would be in order.

Good idea?  Or don't go that way�

It does look quite useful, link? And is it made in ER42?



Thanks John.
--

"ELS! Nothing else works as well for your Lathe"
Automation Artisans Inc.
www dot autoartisans dot com
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Re: [Emc-users] Spindle positioning.

[dave engvall]

On 11/21/21 9:24 PM, John Dammeyer wrote:

I'm running my AC Servo spindle motor as step/dir and can easily tell LCNC to 
do 1 RPM.   I also have the quadrature encoder on it so I can do power tapping. 
 The drive is through the MESA 7i92H as one of the stepper channels as is the 
encoder signals.
  
Is there a way to tell the spindle to turn until it finds the index and stop so it's always stopping at the exact same spot?  Like decelerate to 0.5 rev per second  (30 RPM) or slower and stop when the index happens?  With either an M5 or the button on the user interface?
  
I currently have acceleration/deceleration set high so it reverses quickly with power tapping.  Not to mention the ratio from motor to spindle isn't quite 1:1 because I didn't turn the pulleys exactly the same diameter or groove depth.  But on an M5 a deceleration to 30 RPM and then a complete stop on the index edge.
  
Thanks

John
Some of the '80 vintage Mazaks used a hydraulic cam to index the 
spindle. Fast and positive.
Stop the spindle, rotate with cam which locks orientation for tool 
change, change tool, get the cam clear of the drive pin, start spindle.


If I were  doing that  today I would use 3 sensors. IOW a guard sensor 
either side of index, rotate quickly to detection of guard slow way down 
and search for the central sensor. How you know which is the shortest 
path is left as an exercise for the "student". ;-) Or maybe one simply 
defaults to searching in one direction.


If you don't need orientation then a stepper motor and a gear would seem 
to be as simplistic as one can get.


Dave

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Re: [Emc-users] Power Draw Bar

[dave engvall]

In converting my Mazak I just tied a toggle switch to the control line 
for the valve that ran the hydraulics for tool release. One hand on the 
switch and one on the tool. Rather crude but it worked until the 
belleville stack broke.


Dave

On 11/14/21 4:02 AM, Roland Jollivet wrote:

On a BT30 spindle;
A button the front of the sindle, drawbar is depressed only as long as you
hold the button in.



On Sun, 14 Nov 2021 at 08:03, John Dammeyer  wrote:


Quick question.

On commercial machines that have buttons to load or unload the tool by
actuating the drawbar how are the buttons arranged?

Are there two?  One for Load and one for Unload?  Are they arranged
vertically or horizontally?

If vertically does the upper one load or unload?  If horizontally does the
one on the right load or unload?

Thanks
John


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[Emc-users] 7i90 ethernet link

[dave engvall]

Is anyone using ethernet as a link between linuxcnc and a 7i90?
Comments and/help appreciated

Dave


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Re: [Emc-users] Project Progress

[dave engvall]

For the fussy or perfectionist water cool. Probably water cool the 
ballscrew as heat conduction will be far superior to trying  to cool the 
acetal nut.

Yep! I just fell out of the trees and damaged my head. ;-)

Dave

On 11/4/21 2:46 PM, andy pugh wrote:

On Thu, 4 Nov 2021 at 21:34, John Dammeyer  wrote:

The backlash removal will be a major project.

Maybe https://www.denfordata.com/bb/viewtopic.php?t=3727

Or possibly:
https://photos.app.goo.gl/72BgoRiKeGmQqDHs9
There is a GTEN RSH ballnut in there. They are rather slim but have an
external ball return to deal with. That particular one was
special-order with preload.


--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Project Progress

[dave engvall]

The aquaium pump should keep the sump aerobic. I suppose adding a bit of 
peroxide from time to time would do the same thing. If you let the sump 
go reducing (anaerobic) then the beastie that grow make volatile fatty 
acids and other wonderful smelling ( :-(  ) by-products.

I live in a high desert area and do not seem to have an odor problem.
Obviously YMMV.
Dave

On 11/3/21 11:34 PM, John Dammeyer wrote:

I used the big 1/2" one for the large pocket and the smaller 5mm one for the 
smaller pocket and profile.  The surface finish, given my crappy cast aluminium, was 
really nice.

My mill does have a coolant pump but I don't know if I use the mill often 
enough to fill the reservoir with coolant that then goes mouldy and stinky.  So 
I'm working on a compressed air mist coolant system.  But maybe having a 
secondary reservoir that pumps out the main one and adds an aquarium bubbler 
would work for the flood system.  So in the last 12 years I've never used 
coolant.

John



-Original Message-
From: andrew beck [mailto:andrewbeck0...@gmail.com]
Sent: November-03-21 10:52 PM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Project Progress

What cutters are you using?

As a sideline here in New Zealand I buy and sell tooling so I'm always
testing the limits.

And can probably advise a bit

On Thu, 4 Nov 2021, 11:29 John Dammeyer,  wrote:


I've been using LCNC quite a bit (for me).   In the photo there are two
steel spring collars that were entirely done with the mill.  I could have
left them as large disks with just a stepped hole and the set screw holes
but what's the fun in that.


http://www.autoartisans.com/mill/SpindleControl/TrialFitOnSpindleCover-1.jpg

The spindle cover casting (10lbs of scrap aluminium) was machined in the
places I needed flat surfaces and to get rid of a bit of sag in the casting
mostly for looks.  I'd occasionally spray a bit of WD-40 but mostly just
held the shop vac to clean up the chips.

http://www.autoartisans.com/mill/SpindleControl/SpindleCoverplate-4.jpg

Essentially between 1000 and 2000 RPM, 2 flute 1/2" end mill, 25% step
over, about 2.5 to 5 IPM IPM and a depth of cut of about 0.1" for each
pass.  This created chips that did not melt onto the tool bit and left a
quite nice smooth finish.

But with those parameters it did take quite a while.  OTOH, it ran
automatically and other than check on it periodically and vacuum or blow
away chips I could do other things nearby.

If I enter the parameters into Machinist Toolbox with a target RPM of 1500
I see it suggests a tool feed rate of 21 IPM.  I think that would melt the
chips without flood coolant.  Since I didn't want to screw it up and have
to cast it all over again I was very conservative.

Was I too conservative on this?   It's been suggested by a friend who runs
MACH3 that he dials in a much faster feed and spindle rate and then hauls
back on the sliders to reduce it to very slow and then in small steps bumps
up the speed until it feels right.



Suggestions are welcome.
Thanks
John
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Re: [Emc-users] Prox sensors and wiring

[dave engvall]

Hi Andy,
I have a box of those connectors in a 6 wide and will get a box of 1 
wide and two wide.
My thoughts are when used outside in a marine environment to glop some 
3M Scotchcoat on them. Of course that make them rather fixed but they 
are cheap. :-)


Dave

On 11/4/21 1:44 AM, andy pugh wrote:

On Thu, 4 Nov 2021 at 06:30, John Dammeyer  wrote:


As for connectors, I'd solder and heat shrink to cables if they weren't long 
enough to reach the cabinet.

You can get glue-lined heat-shrink for a truly watertight joint.

I bring the prox leads back to a watertight junction box, and in the
junction box have these:
https://uk.rs-online.com/web/p/pcb-terminal-blocks/8745433/

On a little board  in the box. It makes re-connecting a new prox in an
awkward position rather less painful.
https://photos.app.goo.gl/W85tdizk8BKjV5sf9

Less downtime, as I don't  need to find a new mating connector.

I might be tempted to use these inside a box now.
https://www.amazon.co.uk/gp/product/B08N6G8B1Z





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Re: [Emc-users] Shortening motor shafts

[dave engvall]

I use 1/16" grinding discs all the time for such. I think I'd arrange to 
clamp the shaft  not the motor frame so as to
reduce vibration on the bearings. It it amazing what those discs will do 
at reasonable speeds.


Dave

On 10/17/21 10:27 PM, andrew beck wrote:

Quick and easy way is to use a 1mm cutting disc on a angle grinder.

Slightly harder option is put it in a mill,

clamp the shaft and cut 5mm off

Just don't bang on shaft and you will be sweet.

I would definitely not take them apart that's a headache


On Mon, 18 Oct 2021, 18:12 Ralph Stirling, 
wrote:


I just got a great deal on three 750w brushless servos and drives to
upgrade my cnc mill.  They have the same face dimensions, but the shafts
are 5mm longer than the old brush servos. There was no clearance between
the motor shaft and ball screw inside the coupler, so I need shorten the
32mm long 19mm diam shafts by 5mm.  Can this be done without damage to the
motor from heat or vibration?  I don't want to have to pull the ball screws.

Thanks,
-- Ralph

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Re: [Emc-users] Replacing a handle.

[dave engvall]

Being lazy and cheap I would clamp the piece broken handle side up to a 
plate using a pin thru the hole as a second reference for holding, If 
necessary use a screw thru the hole depending on  size. Now that you 
have it affixed, probe profile and convert to dwg/cad. Machine off the 
casting on the broken side about half way to the knob.


bolt down piece of Al and mil a rough +.01  to +.02 replacement; pin and 
epoxy to handle, finish mill to final dimensions.

Done in two.

Did I miss something obvious?

Dave

On 10/13/21 7:22 AM, Gene Heskett wrote:

On Wednesday 13 October 2021 05:50:52 Dr. Andreas O. Lindner wrote:


Opens OK in Freecad 0.19 on my MAC.

I don't have any mac's, I don't want to test my fire insurance. I am the
long since retired CE at a tv station, a chair I held for 18+ years at
the end of the last century. They bought a couple mac G5's with some gfx
production software several years after I retired, paid about 30 grand
for all of it and both of them went up in flames that needed a fire
extinguisher to put out within 6 months, post mortem found a frozen fan
in each one. Std, BBLB, bronze bushing $0.95 fans. Needless to say, mac
told us to call somebody that cares, and mac's were removed from our
approved purchase list. The station built a new control room complex for
the digital conversion and now broadcasts 8 channels thru 2 transmitters
using 2 linux driven (centos) video file servers built in house. Records
4 channels from a satellite, and plays 4 channels to air each. The owner
died about 4 years back, his daughter sold it to Grey for an obscene
amount, and the first thing they wanted was for linux to disappear, they
were a windows operation. 3+ years later, those servers are still there
and still working, and have never aired a BSOD, so the cash cow never
goes dry, something the windows machines used by the weather channel did
several times daily. MBA's do seem to understand reliability, so I've
not heard of any make linux disappear memos recently.

But they have also lost their linux guy to the fbi at about a 3x raise a
year back. I think there's a potentially costly lesson someplace in
that. ;-)  He built those servers from scratch.



FreeCAD_0.19-23578-Linux-Conda_glibc2.12-x86_64.AppImage, here on stretch
with 32gigs of dram, goes into a cancelable busy loop loading it, and I
let it chew on it for several minutes. No debug output to the terminal
so I've no clue what its upchucking over.


Dr. Andreas O. Lindner

Lindner TAC

[...]

Cheers, Gene Heskett.




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Re: [Emc-users] more dc servo questions

[dave engvall]

Hi,

Fully recognizing that nothing is impossible to the person that doesn't 
have to make it work.  With that proviso I will open
mouth and insert foot. To wit: a sine for acceleration should give a 
more gentle startup and approach to end point. Of course implementation 
is left as an exercise for the student. ;-)

Now I'll shut up and go away.

Dave

On 9/22/21 11:28 AM, Chris Albertson wrote:

So you are driving it with something like this?
amazon.com/HiLetgo-BTS7960-Driver...


One possible mistake is if even for a short time the both enable inputs are
active you will get "shoot through" and short the power supply.Can you
verify this NEVER haens using a scope or logic analyser?   Do not
bother with a software "hal scope"  You need to look at that is actually on
the wires with a device that samples the actual metal pins.  Real pins have
riseand fall times and they can't intersect.

I would also just use one PWM generator and connet it to both LPWM and
RPWM.A safer why to handle L-EN and R_EN is to make 100% certain that
they go through a state where BOTH ARE OFF.  Don't flip them instantly as
there is a finite rise and decay time. There needs to be soome number of
microseconds where both are off.

I bet LCNC flips both L-EN and R_EN on eht same software cycle.  If so then
the supply is shorted via the controller board.

There boards are cheap and another way to fix this is to used a boaed with
a "forward/Reverse" pin rather then two pins sothere is no chance of
enabling both pins.

Or using a "smart" controller with a serial interface where the speed and
direction are sent as a digital command message.   Then the acceletaion and
such is handled by the controller.

The sounds like an short in the h-bridge to me but I could be wrong.  You
can test this with a digital scope. on the control pins.

On Wed, Sep 22, 2021 at 10:21 AM Gene Heskett  wrote:


On Wednesday 22 September 2021 11:44:51 John Figie wrote:


Gene,

I would like to better understand your problem and have been thinking
about this. I have some questions.


I don't think the fact that there is a worm gear matters.  The
problem, I bet is the large inertia of the system.

Hmm I am not sure about the inertia. I think if you have a large gear
reduction then the inertia reflected across the gears should appear
low from the motors point of view.


Aside from proper tuning of the PID gains you could change the
system to use a nested or "cascade" PID.  THis allows the velocity
setpoint to be controlled by the position error
see the section "cascade" in the wiki article
https://en.wikipedia.org/wiki/PID_controller

I think you want a very fast loop i=for the inner PID.  LIkely it
wouldbe in external hardwarelike a microcontroller or FPGA.
(does MESA

do


the PID algorithm in the FPGA?  It should.)



On Sun, Sep 19, 2021 at 3:39 PM Gene Heskett


wrote:

Greetings all;
As most of you know, I built a servo from scratch for a BS-1.

BS-1? What is this? Is this like a Grizzly BS-1 dividing head? Did you
mount the servo motor to this?

Not a grizzly, a Chinese clone.


But I am not at all happy with its performance.
It is a motor with a worm output, driving the worm of the bs-1.
And it has an A/B quad encoder in it.

So you have a 2 worm gear reduction. Where in this system is the
encoder mounted?

On the rear of the motor.


What are the encoder counts per rev of the encoder?

DNK, no index in it.  So I measured the encoder for 100 turns of the BS-1
as verified by the home switch, divided that by 36 to get a count
per degree scale value. Thats about 666.something per degree of the BS-1


What are the motor characteristics?

Brushed PMDC, rated a 100 watts, 24 volts. Intended to run estate gates
by chain drive similar to garage door openers. I assume its OEM
controller has a homing switch, and counts encoder pulses to open so
many pulses when the approaching driver punches his access button.


But I must rather severely limit its run speed because the PID
doesn't see the null coming near fast enough to slow it and stop
a couple

When you say null coming what do you mean? Is this the point where the
desired position is reached according to the motion planner in
LinuxCNC?

Yes. I'd assume so. Motion has its own version.

Null in this context is when the encoder output equals commanded
position.


arcseconds early. I can't allow it to use reverse to stop as the
motor seems to be a near short circuit then, crowbarring the
power supply,

How do you prevent the PWM from reversing the voltage on the motor? Is
the motor driven from a PWM in only one polarity? How is the PWM and
the switches arranged?

Control is by a LCNC PID, fed by the lcnc encoders position output
feeding the PID feedback, with a pwmgen running in mode 2 where it has
two pulse width 

Re: [Emc-users] more dc servo questions

[dave engvall]

Hi all,
To the best of my knowledge any version of the lcnc pid is in software. 
OTOH mesa does offer SOFTDMC which does run in/on mesa fpga products.
However, that breaks the core concept of multiple vendors and real ease 
of user modification of the software although there are a few in this group
that could fiddle the code for an fpga. In addition softdmc needs all 
the support written to wrap around it; interp, task, etc. Years ago I 
head a rumor tht someone had tried to do it and abandoned the effort. If 
I recall correctly it does offer something besides trap accel, controls 
jerk and runs on a 50 us clock.

The manual is available online.
Dave

On 9/19/21 5:12 PM, Chris Albertson wrote:

Is the PID controller running on the PC under LCNC or is this an external
PID controller you built?

What are the numbers, the loop period, motor speed and numer of encoder
lines. and so on?

I don't think the fact that there is a worm gear matters.  The problem, I
bet is the large inertia of the system.

Aside from proper tuning of the PID gains you could change the system to
use a nested or "cascade" PID.  THis allows the velocity setpoint to be
controlled by the position error
see the section "cascade" in the wiki article
https://en.wikipedia.org/wiki/PID_controller

I think you want a very fast loop i=for the inner PID.  LIkely it
wouldbe in external hardwarelike a microcontroller or FPGA.   (does MESA do
the PID algorithm in the FPGA?  It should.)



On Sun, Sep 19, 2021 at 3:39 PM Gene Heskett  wrote:


Greetings all;
As most of you know, I built a servo from scratch for a BS-1.

But I am not at all happy with its performance.
It is a motor with a worm output, driving the worm of the bs-1. And it
has an A/B quad encoder in it.

But I must rather severely limit its run speed because the PID doesn't
see the null coming near fast enough to slow it and stop a couple
arcseconds early. I can't allow it to use reverse to stop as the motor
seems to be a near short circuit then, crowbarring the power supply,
causing a 2 to 3 minute dead time for the 450 watt psu to cool, so I
must limit its speed to disallow its use of reverse to accomplish the
stop.  With 2 worms in series the scale for a 360 degree full turn is of
coarse huge.  If it could be throttled to a gradual stop by anticipating
the coming null, I could probably run it 2 to 4x faster for a cruising
speed.

So my question is, which of the pid inputs would if raised, better
anticipate the approaching null, slowing it over the last 5 angular
minutes of a turn, ideally to a stop within an arc-second of the command
from the gcode?

Thanks all.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] jerk control

[dave engvall]

IIRC emc was conceived as a vehicle to test intercommunication between 
processes and as such higher level features such as lookahead,  
smoothing, etc were not part of the master plan. In fact emc would not 
have had stepping if Matt Shaver had not requested it.


Now on to the real subject of this email. Is there a user that has the 
resources to test linuxcnc vs tiny g for smoothness vis a vis jerk. I 
suspect that tiny g does not have integrated tools to do this so simply 
milling under extreme conditions may be the only way to access the 
utility of its jerk component.

Ideas, comments.
Ray Henry used to talk about tuning by milling before we had good tools 
in emc. It could also be that he was dealing with analog controls. ;-)


Dave

On 8/23/21 5:51 PM, andrew beck wrote:

Andy do you know what the tormach uses for more than 3 axis path blending?



On Tue, Aug 24, 2021, 11:11 AM andy pugh  wrote:


On Mon, 23 Aug 2021 at 21:27, andrew beck 
wrote:

Just had a look at tiny g looks great.

I did try to implement a zero look-ahead finite jerk planner for laser
rastering. It was interesting, and I learned a bit.

It is easier the less general you make it.

Ideally LinuxCNC would have a 9-axis finite-jerk planner that handled
arbitrary kinematics with feed-override control.

Tiny-G is a 3-axis (I think) planner with trivial kinematics and no
feed override (AFAIK).

At the moment I would be happy just to see LinuxCNC handle more than
3-axis blending. It's in Tormach.

I have a feeling that kinematics is not a problem in most cases, the
kins functions run fast enough to be used for finite-difference
differentiation / numerical integration.
I am not sure about the more computationally intensive ones, such as
genserkins. (I think that is fast forwards, slow inverse)

--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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[Emc-users] jerk and a bit of humor

[dave engvall]

read all the way to the bottom for the humor.


https://www.linearmotiontips.com/how-to-reduce-jerk-in-linear-motion-systems/

Dave


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Re: [Emc-users] Something went wrong.

[dave engvall]

Hi all,
Everyone has their own favorite way of workholding.  Without good work 
holding nothing good follows. Thin angle stock I clamp in the vise with 
a rectangular block as suggested below. However, my most common approach 
is to bolt it down usually with 1/4" shcs, which implies gr 8. If I 
think I need better position control then drill and ream for dowel pins 
at +.0005 to +001" plus bolts to hold vertically. Or since 95% of my 
work is with steel, or if I get frustrated just weld it to a plate which 
get bolted to the bed. Good workholding burns a lot of time but is 
absolutely necessary. Duh!


Milling cutters: usually TiAlN sans coolant. I've not tried AlCrN coated 
but a local machine shop is getting a mile of path length/cutter! That 
is a lot of chips.
Speeds and feeds: what every you can get away with. With my little 
machine (BP size 1963 vintage) 0.05" axial is about all I can get with 
out it screaming at me. But I will use as much doc as I can get without 
screaming.


I still have no solution for the needle sharp chips I get with 
conventional cutters.


Cutter comp = yes. Rough with tool dia 0.04 over the real dia. Hard to 
get in trouble that way. Edit tool table or change tool  number for 
successive passes.

Spring pass as necessary.

Chip removal: compressed air or vacuum or both like the dental hygienist 
does for cleaning.  OK for one-offs but production needs a better idea.


That's my tuppence; machining is an adaptive and dynamic process.

Dave
On 8/4/21 6:54 AM, Cristian Bontas wrote:

Hi

I would do it about the same way you did it first, with a few changes.

First, clamp it as high as possible on the vertical part. Get rid of 
the cylinder, or if the vise is not clamping properly without, use a 
thinner one (say 6-8 mm diameter) placed as close to the upper lip as 
possible.


Support the horizontal part. Assuming the top of the vise below the 
overhanging part is flat and horizontal, make a small block to support 
it. Clamping the part would start with pressing it on this block, then 
tightening the vise. Make a long clamp to press down on the part over 
the block - might need to use two screws on either side of the vise. 
Place a bit of Al or Cu wire between the part and the clamp, as at 
this length it will bend. Machine the part in several cuts, so that 
you can move the clamp and support block so that they don't interfere 
with the cutter and its holder.


On 8/4/2021 00:27, John Dammeyer wrote:
That's a good suggestion John F.  Thanks. I did do some more playing 
around and it's clear the part flexing and the backlash both were at 
fault especially with the plunge to the next depth.


And that brings up another issue.  One of my pet peeves with 
electronics project magazines is they are great at a schematic and 
either point to point wired or PC board but very little energy is 
spent on describing various ways of mounting or installing in a 
cabinet.  Especially with the concept of Human Factor Engineering 
which is the practice of making something easy to use or even 
intuitive.  Like an ESTOP button is always a red mushroom  Not a 
toggle switch.


Same goes with work holding.  Youtube has tons of videos that show a 
tiring sequence of a milling cutter sprayed with coolant making chips 
for 3 minutes with 3 commercials interjected, one every minute.   But 
very little on work holding.


The next part I am making is shown in the attached screen shot 
rendering.  My raw material is in the second photo.  So the question 
is about work holding and how or what features of LinuxCNC can be 
used to make this easier.


I can use my band saw to create the initial width and split it into 
two L shapes.  But after that I start to have problems, due to lack 
of experience I think, on how to firmly hold it and mill the stuff 
with a 5mm and  6.35mm (1/4") cutter.


Suggestions?

Thanks
John



-Original Message-
From: John Figie [mailto:zephyr9...@gmail.com]
Sent: August-03-21 11:59 AM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Something went wrong.

Speaking of backlash. My tiered old Bridgeport has about 0.002" of 
backlash
in the ballscrews. So if circular interpolation is used there is a 
small
bump at each 90 degrees of the circle. But if I make the finish pass 
first

clockwise and then repeat counter clockwise the imperfections are much
smaller. I know from experience with my first CNC machine that's 
built that
actually used leadscrews with lots of backlash the clockwise 
followed by

counter clockwise method was remarkable compared to a single direction
final pass.

John

On Tue, Aug 3, 2021, 10:10 AM jrmitchellj  
wrote:


You might try the run again without the backlash compensation in 
LCNC to

get a feel of what it is actually doing.


--J. Ray Mitchell Jr.


�I predict future happiness for Americans, if they can prevent the
government from wasting the labors of the people under the pretense of
taking care of them.�

THOMAS JEFFERSON


On 

Re: [Emc-users] Something went wrong.

[dave engvall]

HI John,
If I'm reading correctly it is  OK with conventional milling but off 
with climb. Too weird!  I guess the next step would be to mill it 
conventional and overlay with climb and see what happens. Maybe  a bit 
of layout dye between runs.


The alternative would seem to be that Murphy and all his cousins have 
invaded your shop. ;-)

Where is the can of murphycide?

Dave

On 8/2/21 2:59 PM, John Dammeyer wrote:

And here's the other side.  Notice no stair stepping so with conventional 
milling it appears just enough of a load to not show edges.

Really do need ball screws or maybe really tighten up the gibs.  Maybe my 
backlash value entered into LinuxCNC INI file is off a hair?

Anyway, this time the hole is centered in the outer round section.   It was 
clamped the same way the last time.  If it had moved then the RHS width would 
have also changed relative to the pretty close to round hole.

Anyway.  Lots to learn.
John




-Original Message-
From: jrmitchellj [mailto:jrmitche...@gmail.com]
Sent: August-02-21 2:10 PM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Something went wrong.

It would be interesting for me to see how the part was held in the machine.

--J. Ray Mitchell Jr.


�I predict future happiness for Americans, if they can prevent the
government from wasting the labors of the people under the pretense of
taking care of them.�

THOMAS JEFFERSON


On Mon, Aug 2, 2021 at 10:10 AM John Dammeyer 
wrote:


Same tool for both inner hole and outer profile.
Same feeds and speeds and conventional, not climb milling.
G40  -- No compensation.
Only I,J in the file with a G17 preceding them.

I could hide it considering what it's for and that no one will see it.
But that's not really the point.  I'd know.

Will try it again today this time with entry exit for each pass rather
than just the first and last.

John


-Original Message-
From: Ralph Stirling [mailto:ralph.stirl...@wallawalla.edu]
Sent: August-02-21 8:12 AM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Something went wrong.

To elaborate a little more, your description sounds a bit like G42

cutter compensation, described in

https://linuxcnc.org/docs/2.8/html/gcode/tool-compensation.html .

-- Ralph

On Aug 2, 2021 6:12 AM, Ralph Stirling 

wrote:

CAUTION: This email originated from outside the Walla Walla University

email system.


Cutter compensation enabled?

On Aug 1, 2021 7:26 PM, John Dammeyer  wrote:
CAUTION: This email originated from outside the Walla Walla University

email system.


The milling operation was set up to always be climb milling. Zero point

for the center hole and the outside perimeter was the same.

And yet it milled more away on the LH side.

The piece was tightly clamped and did not move.  The width of the

perimeter on the RHS is correct with the outer diameter at 45mm

and the inner hole at 32.5mm.

ie. At the RHS it's 6.25mm wide and on the LHS it's 4mm so it's the

milling of the outer that shifted.  The inner circle is pretty well

round.  Not as good as a boring tool but still round.

The inner hole was done after the outer perimeter.

Very odd and I don't understand why.  LinuxCNC and the motor drives did

not throw up any faults.

S1100
Feed was 307mm/min with 1/4" 2 flute cutter.
Total depth was 3.2mm and depth per pass 0.9mm.
WD-40 and compressed air.

John



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Re: [Emc-users] Something went wrong.

[dave engvall]

Weird! Is it repeatable? Did the program use R or I,J? Just fishing? ;-)

Dave

On 8/1/21 7:25 PM, John Dammeyer wrote:

The milling operation was set up to always be climb milling. Zero point for the 
center hole and the outside perimeter was the same.  And yet it milled more 
away on the LH side.

The piece was tightly clamped and did not move.  The width of the perimeter on 
the RHS is correct with the outer diameter at 45mm and the inner hole at 32.5mm.

ie. At the RHS it's 6.25mm wide and on the LHS it's 4mm so it's the milling of 
the outer that shifted.  The inner circle is pretty well round.  Not as good as 
a boring tool but still round.

The inner hole was done after the outer perimeter.

Very odd and I don't understand why.  LinuxCNC and the motor drives did not 
throw up any faults.
S1100
Feed was 307mm/min with 1/4" 2 flute cutter.
Total depth was 3.2mm and depth per pass 0.9mm.
WD-40 and compressed air.

John




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Re: [Emc-users] electrical inspection pain

[dave engvall]

Although electrical inspectors tend to be a  power unto themselves they 
still have to follow the rules. i.e. WAC's and local and national 
electrical codes. Be as gentle as possible they tend to be prickly. 
Being WW they no doubt see a bunch of EU stuff for wineries. Clearly the 
machine didn't need approval in its former location. If there is no 
clear authority for what he is demanding then he is out in left field. 
Good luck.


Dave

On 7/28/21 1:22 PM, Dave Cole wrote:

IMO, your building inspector is stepping way outside of his authority.
His job is "building" inspection.   You got a permit for your 
"building" project.    Not for some machine sitting in your building.


Unless your mill is part of the "building",  he is way outside of his 
authority.


If your mill is hardwired into your electrical system, that may be a 
problem.  You may need to have a plug and receptacle for your mill, 
with the appropriate branch circuit protection (circuit breaker or 
fuse, etc) for the outlet.


I would ask specifically why he believes your machine must be stamped 
when it is not part of your building.   Record exactly what he says.   
Try and do as much in writing as possible. Emails work.  Ask them what 
standard codes they follow and ask them to cite the sections of the 
code they are basing their decision on.   Then appeal his decision.   
Tell the guy you mean no disrespect, but that you disagree with his 
decision and want to appeal it.
They should have a process to do that.   Chances are that his boss 
will not support his decision. Unless everything used in your county 
is required to be UL approved (very unlikely), I think his decision 
will be overturned.    7 engineers in the state who can apply a stamp 
are  inadequate to cover all of WA state!   Just make sure you are 
decent about it.   People become irrational when they feel attacked.
If they push back you need to remind them that you are suffering from 
loss of use due to what you believe is an arbitrary decision.


Do you know any lawyers in the area? If you can, you want to copy a 
lawyer on all of your correspondence.    The lawyer doesn't need to do 
anything typically if you follow the appeals process.   But including 
legal counsel raises the bar significantly on their part.   Tell the 
lawyer you want to copy them in case they are needed.  Etc.
When things get sticky for the inspectors, and you have legit 
arguments, they will typically back off.   Getting legal counsel 
involved is incredibly sticky since they have to get "their" legal 
counsel involved as well, and that costs $$, it sparks internal 
meetings.   Lots of paperwork, etc. Suddenly you turn into a plague on 
the department.


I do industrial integration and have been doing it since 2003.   I 
have LinuxCNC machines running in plants everyday.

But I'm in Indiana.

Dave


On 7/28/2021 3:14 PM, Ralph Stirling wrote:

I'm in a bind now.  I just had the electrical wiring I put
into my garage shop inspected.  The WA state inspector
liked my wiring fine, but balked at the non-UL-listed
CNC mill (the main point to my whole garage shop project).
He insists it get stamped by one of the *seven* official
"approved engineers" for the state of WA before he can
sign off on my electric.  I suspect that the field approval
would cost considerably more than my entire mill (1998
vintage French 5hp spindle, 300x200x300mm travels,
$5K).  Didn't matter to him that the new VFD is listed.

Any other US-based, especially WA-based LinuxCNC
retrofitters faced this problem successfully?

Thanks,
-- Ralph

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Re: [Emc-users] A new lathe encoder option.

[dave engvall]

"The solution is to either add more counts per revolution or use a ten 
timesmore complex control algorithm."


IIUC then the real problem here is statistical. That is the sample size is too 
small to be significant. Maybe an over-simplification of the issue but:

I think there are a couple of ways to approach this. (1) time stamp the 
index pulse.
               (2) use a high count encoder and scale as necessary. 
This is clearly limited by the response of the  optics    for the disc.  
100 - 200 KHz for the inexpensive stuff.
I don't think there is a one size fits all solution. In electronic terms 
lathe spindles are pretty slow and have a lot of angular momentum. Most 
lathe spindles

rpm range is not a lot over 5-6 binary bits.


Just late evening rattling the cage. (off coffee until sunrise).

Dave






Could you solve the noise issue with a phase-locked loop?

Yes, this would be a far better solution. But I didn't want to
re-write the encoder counter from scratch.

Ideally you would use two PLLs, one for the pulses and one for the
index, to predict the pulse gap and extrapolate through it.

--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
� George Fitch, Atlanta Constitution Newspaper, 1912

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Re: [Emc-users] A new lathe encoder option.

[dave engvall]

"The solution is to either add more counts per revolution or use a ten 
timesmore complex control algorithm."


IIUC then the real problem here is statistical. That is the sample size is too 
small to be significant. Maybe an over-simplification of the issue but:

I think there are a couple of ways to approach this. (1) time stamp the 
index pulse.
         (2) use a high count encoder and scale as necessary. This 
is clearly limited by the response of the  optics  for the disc.  
100 - 200 KHz for the inexpensive stuff.
I don't think there is a one size fits all solution. In electronic terms 
lathe spindles are pretty slow and have a lot of angular momentum. Most 
lathe spindle

rpm range is not a lot over 5-6 binary bits.
I've actually considered putting a disc brake on the spindle. Not 
exactly joking.


Just late evening rattling the cage.

Dave







Could you solve the noise issue with a phase-locked loop?

Yes, this would be a far better solution. But I didn't want to
re-write the encoder counter from scratch.

Ideally you would use two PLLs, one for the pulses and one for the
index, to predict the pulse gap and extrapolate through it.

--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
� George Fitch, Atlanta Constitution Newspaper, 1912

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[Emc-users] center of circle

[dave engvall]

https://math.stackexchange.com/questions/213658/get-the-equation-of-a-circle-when-given-3-points 




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Re: [Emc-users] OT: power, horsepower, and a bad brain

[dave engvall]

Hi,
Alternators like to be spun fast. Max rpm 10K but 6Krpm is a good place 
to operate. It is easy to damage pb-acid batteries while charging.
See 
https://www.solar-electric.com/lib/wind-sun/Iota-charging-deep-cycle-batteries.pdf


There are better guides on the web but this is the first one that came up.
In summary bulk charge to about 25% of total capacity. Absorbtion charge 
up to the recommended voltage then float charge.
One can fast charge a battery but the chances of damage increase. I 
think the 10 A rate of most 12 chargers is reasonable.
A serious web search should give better figures. To charge at high rates 
is going to take a very large battery. ;-)
I suspect that charging batteries in series will help level out the 
charge when charging multiple batteries. Of course that takes a different

alternator. ;-(  As always YMMV
Good luck.

Dave


On 7/9/21 9:46 AM, fxkl47BF via Emc-users wrote:

On Sunday, June 27th, 2021 at 6:41 AM, fxkl47BF  wrote:


i'm gonna explain my screwup here because this group of folks has a very 
diverse range of expertise. enough kiss'n up. if you know of a list that would 
be more appropriate please let me know.
i've had a desire for some time to build a gasoline powered battery charger. 
i've seen it done several times and thought no big deal. my first thought was 
to use a 3 hp engine and a 100 amp one wire alternator. but since i already had 
a 6.5 hp engine i decided to go with that and an alternator like this 
https://www.ebay.com/itm/NEW-CS130-ONE-WIRE-RED-ALTERNATOR-FOR-CHEVROLET-GMC-CHEVY-220-AMP-1-WIRE-1100665-/283190864732?hash=item41ef7dab5c.
 i also added an ammeter like this 
https://www.ebay.com/itm/30474999?hash=item461ba47b37:g:hYUAAOxy4fVTEuR6.
i finished it and was ready to test. i pulled a big battery out of my tractor, 
connected a 1000 watt inverter, and about an 800 watt load. i cranked the 
engine and connected it to the battery. ammeter showed about a 7 amp load. i 
switched on the inverter and it went to about 9 amps. i switched on the load 
and it went to about 75 amps. the engine was straining. i disconnected the the 
alternator from the battery so the load could draw down the battery. after 
about one minute i reconnected the alternator. the ammeter jumped to about 110 
amps and it promptly stalled the engine. i tried several times with the same 
results.
all of my feeble calculations led me to believe that a 6.5 hp gasoline engine 
was more than enough to power a 220 amp 12 volt alternator. either my 6.5 hp 
engine is more feeble than my brain or my calculations are way off.
thanks for any feedback.

i've been do'n a little piddle'n on this when life didn't get in the way.
i took all of the feedback from y'all and it sounded like less would be better 
so where my sheaves were originally a 2:1 increase now i have a 1:1. i tried 
slower, .7:1 decrease but it was too slow. the alternator would barely make 13 
volts. to get a little more info i bought one of those point and shoot 
tachometers. it says this engine runs at 3200 rpm with no load. with a 1:1 
ratio i drained down my battery and with a 800 watt load the alternator made 
120 amps at 14.3 volts for 20 to 30 seconds before the amps dropped. the tach 
showed it turning at 3100 rpm. i think to get 220 amps i would need a 10 or 12 
hp engine and turn this thing at 1 rpm. of course it would melt down after 
about 1 minute.
i appreciate all the feedback.


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Re: [Emc-users] Code of Conduct

[dave engvall]

From my view as a 'older' person: the CoC simply weaponizes those who 
want to be nasty.
I visit another forum where about half the members are polite and the 
other half apparently didn't get much parenting . profane, 
aggressive, nasty, lacking basic spelling and language skills, etc. 
Needless to say I'm not going to name names.

To quote or  paraphrase MT "why does common sense seem to  be so uncommon".

On 6/29/21 5:14 AM, fxkl47BF via Emc-users wrote:

‐‐‐ Original Message ‐‐‐

On Tuesday, June 29th, 2021 at 3:52 AM, Robert Murphy  
wrote:


I have a feeling that there is a boiler plate/template for the Code of Conduct.
Rumours abound relating to projects being forced to have one.

have one or be labeled non-conformist and be boycotted


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[Emc-users] another printer project?

[dave engvall]

https://www.globalspec.com/FeaturedProducts/Detail?ExhibitID=325495=%2D1103937792=d47436=210629=d253f6=Vol21Issue26=1=2070084=link%5F2070084=367418=95281=newsletter=nl=414029 




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Re: [Emc-users] Machining question

[dave engvall]

On the Z for my Cinci I cheat by running the encoder off a small idler 
driven by the belt between the servo and the ball screw. Gets me about 
5X number of counts. In more practical terms ~100K count/in. Encoders 
off the end of the ball screws are 40K/in.
I pretty much standardize on Koyo 2500 cpr light duty encoders at about 
$90 a pop. Couplers are helicoil and I've lost a couple in 20 years of 
operation. Very careful alignment in mounting helps. Only way I know to 
do much better is to use the Fanuc 'red cap' encoders.


Dave

On 6/19/21 6:16 PM, Gene Heskett wrote:

On Saturday 19 June 2021 18:57:42 John Dammeyer wrote:


But doesn't the 7i92 FPGA deal with quadrature encoders and therefore
doesn't really need to deal with a sampling process but instead looks
at edges?  And because of the way quadrature works, with the A/B
phasing you don't get the same types of errors compared to polling a
bit level X times per second and trying to decide when it's high/low.

John

Sure the quadrature decoder is the best, but to avoid quantization noise,
it must count a large number of edges going by for each sample time it
records how many edges have gone by THIS time. My original home made
encoder wheel on the G0704 had 74 slots, which was about as fine as I
could machine in a 30 thou thick brass disk. Each slot had 2 edges, and
with the slot interruptors spaced to be about 90 degrees apart, that was
around 276 edges per revolution. So it was at 500 revs, and a 1 khz
sample rate, blessed with quantization noise such that it was hammering
the nylon gears, making it sound as if all the bearings had square balls
in them since the controller was slapping both faces of the gears trying
to do 600 revs on one sample and 400 revs on the next sample a
millisecond later.

So I drilled and tapped the back of the motor shaft and fitted an
extension to drive a $20 1000 line encoder I got from fleabay.
quantization noise dissapeared, and I now have to look at the spindle to
see if its running, even at 500 revs, its dead silent. A 1/4-28 tap
bites into steel and I get no audible loading indication with a Pgain
above 1000 until Jons servo amp current limits at about 18 amps, making
the motor iron chirp.  On the old encoder, Pgain above 3 went crazy.

Bottom line: within the limits of your bobs bandwidth, (by-pass the optos
in it) the more resolution you can put into the encoder, the smnoother
and quieter it will run. My SCALE_HIGH and SCALE_LOW are above 7100 and
14300 per revolution. In either case, quantization noise is down in the
very closely cropped grass, very close to invisible on the halscope.



-Original Message-
From: Chris Albertson [mailto:albertson.ch...@gmail.com]
Sent: June-19-21 3:21 PM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Machining question

There are two kinds of noise,
1) electrical noise superimposed on the signal.
2) quantization noise from the sampling process.  What happens here
is that the computer counts the number of line crossings during a
given time.  it is just random luck when the time starts so on
average there is a plus or minus one count error.

So a one count error sounds small but lets say we have a 600 count
encoder and we are running at 500 RPM and sampling 100 times per
second. This works out to 50 counts per period.  a one count error
is a 2% error. You will see a larger percent error at slower speeds
or with a lower resolution encoder.

So even with perfect wires and perfect grounding and zero electrical
noise the RPM speed is going to jump around randomly over a 4 RPM
range because of unavoidable quantization error.

The solutions either the use a larger sample time apply a low-pass
DIGITAL filter to the signal.  No amount of analog filters on the
wires will work.

On Sat, Jun 19, 2021 at 2:55 PM Gene Heskett 

wrote:

On Saturday 19 June 2021 12:59:19 John Dammeyer wrote:

I need to do a couple of things.  For one the AC Servo makes a
lot of electrical noise.  The frame of the motor is connected to
earth through power line ground.  But my bench setup has the
control side 5V not isolated from the 'PC' side (optos are kind
of useless here) and although the Pi4 doesn't appear to have any
trouble the scope shows a pretty noisy encoder signal.

You are about to learn the star ground system I think.

Thats where all grounds go to a single bolt, and no other grounds
are allowed anyplace.

Shielding in motor cables ends without touching the motor, only
connected to this same single bolt which is grounded. The common
line of any power supply is connected only to this bolt, and the
common grounds to every piece of pcb in the system comes from that
bolt. The used to be green static ground wire in any power cord is
rerouted to this bolt. And static grounds on a power supply are
fed from this single bolt. Because the psu case is usually bolted
down wherever its at, you may have to uncover the supply and
remove any connection from the earth labeled terminal, and the

Re: [Emc-users] Machining question

[dave engvall]

It is not unusual for shaft mounted encoders to have some strain relief 
rather than a hard connection. see link.

https://www.shopcross.com/zo-.25bore-200ppr?msclkid=0c56646795e81faf9ef104ab7e98b74f_source=bing_medium=cpc_campaign=(ROI)%20Shopping%20-%20No%20Numbers_term=4586406598964502_content=Everything%20Else
YMMV

Dave

On 6/18/21 11:04 AM, Gregg Eshelman via Emc-users wrote:

  Reamers can be some fun stuff. I hand reamed the spindle on a 1913 Sears Expert (made by South Bend, an 
"Old, reliable" manufacturer that was all of 4 years old back then) 14" metal lathe out to 
just over 3/4". The ends of the spindle bore were just a hair over 3/4" but in between was smaller 
and pretty rough. I wanted to have it able to pass a 3/4" diameter bar all the way through, so I made it 
happen, one small increment at a time.


 On Friday, June 18, 2021, 11:07:09 AM MDT, Gerrit Visser  
wrote:
  
  Reamers don't work well in nominal size holes. So always leave enough meat ofr it to do its work. The attached link gives good info on that topic.


Machine reamers cut on the leading edge only, there is no taper. Hand reamers 
have a taper, and won't cut to a shoulder.

If concentricity is the key goal, then drill well under size, bore to reamer 
alloance and then ream.

https://www.fltechnical.com/news/reamer-guide-basic-technical-information-for-reamers

Gerrit

-Original Message-
From: John Dammeyer 
Sent: June 18, 2021 11:49 AM
To: Enhanced Machine Controller (EMC) 
Subject: [Emc-users] Machining question

This isn't as much a LinuxCNC question but more of an approach to how to 
machine something.
  
The attached photo shows a coupler from a 3/8" encoder to 14mm Servo Motor so I can test on the bench the Pi4 closed loop encoder behavior.
  
This one didn't turn out very well.  I drilled all the way through and then used a reamer to bring it to 3/8".  It's a firm sliding fit on the encoder shaft.  Without removing it from the chuck I then drilled halfway to 13mm and then used a 14mm reamer to bring it to size, testing with the motor shaft.
  
Problem was the reamer was slightly tapered at the front so it did a poor job.  I finished it up with the boring tool but maybe a few thou too large.  However the wobble seems much worse than that.
  
I'm thinking the better approach would be to drill all the way through undersize 3/8" and then drill half way with 13mm.  Then only use the boring tool to bring the back half up to 3/8" and the front up to 14mm.  This way if the initial hole wasn't concentric with rotation the boring tool would ensure it is.
  
Make sense?  Or is there a better way?
  
Thanks

John
   
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Re: [Emc-users] looking for info on yaskawa servo drive model numbers from morbidelli cnc router

[dave engvall]

file:///tmp/mozilla_dave0/MTN-696TBC-1.pdf

On 5/24/21 7:12 AM, Andrew wrote:

пн, 24 трав. 2021 о 13:41 andrew beck  пише:


I don't think it has any USB connectors.

I do know that the io controls all go through the plugs on the bottom.  One
for encoder feedback from motor.

One for the input signal.

There are several notes on serial control in all the manuals I have read.
But I know some models do step dir and some do analog.


Here's the solution.
You can use SigmaWin to connect to the drive (3CN connector) and look at
the parameters and find if there's anything related to analog control.
The PC cable pinout is in the SGDB manual.

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Re: [Emc-users] homing off glass scale

[dave engvall]

Talk about having a bad day. Sure glad the extras were just a recipe and 
not something private. :-)


Dave

ps. clear down at the bottom of the post is the 'real post' about homing 
with a glass scale.

You can delete  90% of it and won't miss a thing.


On 5/22/21 8:09 AM, dave engvall wrote:


 Instructions

 *
   Rinse and pat the shrimp dry, then transfer to a large mixing bowl.
   Drizzle with 1/2 tablespoon olive oil and sprinkle with the chili
   powder, chipotle chili, cumin, and salt. Toss to coat evenly. Let
   rest while you prepare the shrimp taco sauce and slaw.
 *
   Prepare the sauce and slaw: In a food processor fitted with a steel
   blade, process the Greek yogurt, olive oil, garlic, jalapeno,
   cilantro, salt, lime zest, and lime juice. Taste and adjust
   seasonings as desired. Place the cabbage in a mixing bowl and toss
   with about 1/2 cup of the sauce. Add more sauce if you desire a
   creamier slaw, then reserve the rest of the sauce for serving.
 *
   Cook the shrimp: In a large nonstick skillet over medium high, heat
   the remaining 1/2 tablespoon olive oil. Add the shrimp and sauté
   just until the shrimp is cooked through and no longer translucent in
   the center, about 4 minutes. Do not overcook! Transfer
   the shrimp immediately to a plate.
 *
   Warm the tortillas (optional) and assemble the tacos: If you like,
   warm the tortillas in the microwave (put them in a stack and cover
   them with a lightly damp towel) or a 250 degree F oven while
   the shrimp cook. To serve, fill the tortillas with your desired
   number of shrimp, then top generously with the slaw, extra sauce, a
   squeeze of lime juice, and any other desired toppings. Enjoy
   immediately.


 Notes

 * The shrimp tastes best the day it is made but can be stored in the
   refrigerator for up to 3 days. Since shrimp tends to dry out when
   reheated, I prefer to use the leftovers on top of salads. Slaw can
   be stored in the refrigerator for up to 2 days, and any extra sauce
   can be refrigerated for up to 5 days.


 Nutrition

*Serving*: 1taco (of 8), including tortilla, shrimp, and slaw
*Calories*: 158kcal
*Carbohydrates*: 14g
*Protein*: 13g
*Fat*: 6g
*Saturated Fat*: 1g
*Cholesterol*: 1mg
*Fiber*: 2gSugar: 3g

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[Emc-users] homing off glass scale

[dave engvall]

 Instructions

 *
   Rinse and pat the shrimp dry, then transfer to a large mixing bowl.
   Drizzle with 1/2 tablespoon olive oil and sprinkle with the chili
   powder, chipotle chili, cumin, and salt. Toss to coat evenly. Let
   rest while you prepare the shrimp taco sauce and slaw.
 *
   Prepare the sauce and slaw: In a food processor fitted with a steel
   blade, process the Greek yogurt, olive oil, garlic, jalapeno,
   cilantro, salt, lime zest, and lime juice. Taste and adjust
   seasonings as desired. Place the cabbage in a mixing bowl and toss
   with about 1/2 cup of the sauce. Add more sauce if you desire a
   creamier slaw, then reserve the rest of the sauce for serving.
 *
   Cook the shrimp: In a large nonstick skillet over medium high, heat
   the remaining 1/2 tablespoon olive oil. Add the shrimp and sauté
   just until the shrimp is cooked through and no longer translucent in
   the center, about 4 minutes. Do not overcook! Transfer
   the shrimp immediately to a plate.
 *
   Warm the tortillas (optional) and assemble the tacos: If you like,
   warm the tortillas in the microwave (put them in a stack and cover
   them with a lightly damp towel) or a 250 degree F oven while
   the shrimp cook. To serve, fill the tortillas with your desired
   number of shrimp, then top generously with the slaw, extra sauce, a
   squeeze of lime juice, and any other desired toppings. Enjoy
   immediately.


 Notes

 * The shrimp tastes best the day it is made but can be stored in the
   refrigerator for up to 3 days. Since shrimp tends to dry out when
   reheated, I prefer to use the leftovers on top of salads. Slaw can
   be stored in the refrigerator for up to 2 days, and any extra sauce
   can be refrigerated for up to 5 days.


 Nutrition

*Serving*: 1taco (of 8), including tortilla, shrimp, and slaw
*Calories*: 158kcal
*Carbohydrates*: 14g
*Protein*: 13g
*Fat*: 6g
*Saturated Fat*: 1g
*Cholesterol*: 1mg
*Fiber*: 2gSugar: 3g

Advertisement

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 * Instant Pot Chicken Tikka Masala Recipe
   


   413 saves
 * Harvest Chicken Skillet with Sweet Potatoes Brussels Sprouts and
   Sautéed Apples
   


   375 saves
 * Slow Cooker Honey Garlic Chicken Recipe
   


   216 saves

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2018. This article is republished here with permission.


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Advertisement


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 * 




   How To Make Better-than-Takeout Beef and Broccoli in the
   Slow Cooker

   

 * 


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 * 




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 * 


   How to Make Marinara Sauce

   
 * 


   How To Make French Onion Soup

   


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 * Coronavirus 
 * Business 
 * Career 
 * Education 
 * Entertainment 
 * Food 
 * Gaming 
 * Health & Fitness 
 * Parenting 
 * Personal Finance 
 * Politics 

[Emc-users] Chinese glass scale

[dave engvall]

Hi all,
Just as a matter of interest I thought I'd throw this out there.
A while ago I messed up one of my acu-rite glass scales ( boo-hoo!)
It goes off for repair and I mounted a Chinese glass scale as a temp 
replacement.

This is mounted on the X of my Cinci contoumaster. Year of manufacture 1963.
I did the same data collection on my acu-rite and it came up dead on for 
all values.

Both are 5 um scales.
The screw values were taken off the hand crank adjusted as close to zero 
as my eyes  can determine.
I didn't bother to use a glass on the dial. Of course all values were 
approached from the low side. The ball

screw has about 0.004 backlash.
The 1 um scales are not much more than the 5 um scales which makes 
almost no real difference if you are

hand cranking but for servo use the extra counts may help tuning the servo.

screw  dro  dev
0    0             0
1        0.9986    0.0014
2    1.9992    0.0008
3    2.9996    0.0004
4    3.9998    0.0002
5        5     0
6    6     0
7    7             0
8    7.9998    0.0002
9    9.0002    -0.0002
10    10.0002    -0.0002
11    11              0
12    12.0002    -0.0002
13    13.0002    -0.0002
14    14.0012    -0.0012
15    15.001       -0.001
16    16.0012    -0.0012
17    17.     0.0
18    18.001      -0.001
19    19.0012    -0.0012
20    20.0014    -0.0014
21    21.001       -0.001



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[Emc-users] 7i43 usage

[dave engvall]

Hi all,
I'm trying to use a 7i43 I've had on the shelf for awhile.
200K version despite the error message. :-)

I've tried it on several motherboards and several paraport cards with 
pretty much the same result.

Hopefully someone can give me a hint of what is really wrong.

Below is the message I get:

LINUXCNC - 2.7.14
Machine configuration directory is 
'/home/dave/linuxcnc/configs/by_interface.mesa.hm2-servo'

Machine configuration file is '7i43-small.ini'
Starting LinuxCNC...
Found file(REL): ./hm2-servo.hal
Note: Using POSIX realtime
hm2: loading Mesa HostMot2 driver version 0.15
hm2_7i43: loading HostMot2 Mesa 7i43 driver version 0.3
hm2_7i43: failed to clear EPP Timeout!
hm2_7i43: /DONE is not low after CPLD reset!
hm2/hm2_7i43.0: board has FPGA '3s400tq144', but the firmware in 
hm2/7i43-2/SVST4_4.BIT is for FPGA '3s200tq144'
hm2_7i43.0: board at (ioaddr=0x0378, ioaddr_hi=0x, epp_wide ON) not 
found!

hm2_7i43: rtapi_app_main: Invalid argument (-22)
./hm2-servo.hal:43: waitpid failed /usr/bin/rtapi_app hm2_7i43
./hm2-servo.hal:43: /usr/bin/rtapi_app exited without becoming ready
./hm2-servo.hal:43: insmod for hm2_7i43 failed, returned -1
Shutting down and cleaning up LinuxCNC...
hm2: unloading
Note: Using POSIX realtime

So  is there a cure or do I go find another approach?

TIA

Dave


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Re: [Emc-users] Rpi4B OS

[dave engvall]

So if I have a raspian os running that will run linuxcnc  ??? an arm 
version that is.

...and I've   gone thru a  whole lot of angst for nothing?
Dave

On 4/7/21 9:02 AM, Gene Heskett wrote:

On Wednesday 07 April 2021 01:24:35 dave engvall wrote:

You can use dd, on an x86 box to write the u-sd card, that is not the
problem, but here is the problem, you did NOT start with the raspbian
#.iso file. It will be complete with all that.


OK, so I download 20210210_raspi_4_buster.img.xz

 From what url, I'll look and make sure you can get the right stuff.


check sha256 and it matches
make a *.img out of it.
attempt to install the rpi-imager   no x86 version.   so use dd
dd to SD:   dd bs = 1M if=202010210-raspi_4.buster.img
of=/media/dave/3339-3839/rpi_4_buster
unmount
put SD in rpi4B and power up
get the same error  messages as before:

autoboot.txt not found
config.txt not found
recover4.elf not found
recovery.elf not found
start.elf not found
SD boot failed

So is the .img missing bits and pieces or are there steps beyond the
dd of the image that need to
add the missing files?  If so where do I look for these files?

Dave

On 4/6/21 4:47 PM, andy pugh wrote:

On Tue, 6 Apr 2021 at 22:56, Feral Engineer

 wrote:

Have you experienced crashes in lcnc on a pi4b?

TBH I haven't really used it. I have lots of other LinuxCNC machines
which actually have monitors.

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Re: [Emc-users] Rpi4B OS

[dave engvall]

Confusion reigns!
The idea is to use the pi to drive a 7i90->7i33
I just tried the link John recommended .. 2.8.1 with the same result so 
it looks like I need to shift gears.
I'm lost;  I just need a version that will run linuxcnc with servos. 
Agnostic about which version.
If raspianos with uspace(?) will do that I'm happy. I just need 
something to WORK. ;-)
With some pain I can use my wife's  Mac and the rpi-tools to get an 
image on to the SD.

Wandering in the wilderness.

Dave


On 4/7/21 7:31 AM, andy pugh wrote:

On Wed, 7 Apr 2021 at 15:25, dave engvall  wrote:

Image is one at top of page.  buster 4 G
https://raspi.debian.net/tested-images/

Do you actually want to run LinuxCNC on the Pi?

Why are you using the Debian image rather than the official Raspbian
one, or the LinuxCNC one.





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Re: [Emc-users] Rpi4B OS

[dave engvall]

Image is one at top of page.  buster 4 G
https://raspi.debian.net/tested-images/

I'm doing everything  on a I7 with Ubuntu 16.04.1 then write to 32G SD 
an take that to the pi.


Dave

On 4/7/21 12:49 AM, andy pugh wrote:

On Wed, 7 Apr 2021 at 06:28, dave engvall  wrote:


attempt to install the rpi-imager   no x86 version.   so use dd

There is a Pi Imager .deb here.
https://downloads.raspberrypi.org/imager/imager_latest_amd64.deb

Or are you running a 32 bit kernel?





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Re: [Emc-users] Rpi4B OS

[dave engvall]

On 4/6/21 10:24 PM, dave engvall wrote:

OK, so I download 20210210_raspi_4_buster.img.xz
check sha256 and it matches
make a *.img out of it.
attempt to install the rpi-imager   no x86 version.   so use dd
dd to SD:   dd bs = 1M if=202010210-raspi_4.buster.img 
of=/media/dave/3339-3839/rpi_4_buster

unmount
put SD in rpi4B and power up
get the same error  messages as before:

autoboot.txt not found
config.txt not found
recover4.elf not found
recovery.elf not found
start.elf not found
SD boot failed

So is the .img missing bits and pieces or are there steps beyond the 
dd of the image that need to

add the missing files?  If so where do I look for these files?

Dave


On 4/6/21 4:47 PM, andy pugh wrote:
On Tue, 6 Apr 2021 at 22:56, Feral Engineer 
 wrote:



Have you experienced crashes in lcnc on a pi4b?

TBH I haven't really used it. I have lots of other LinuxCNC machines
which actually have monitors.





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Re: [Emc-users] Rpi4B OS

[dave engvall]

OK, so I download 20210210_raspi_4_buster.img.xz
check sha256 and it matches
make a *.img out of it.
attempt to install the rpi-imager   no x86 version.   so use dd
dd to SD:   dd bs = 1M if=202010210-raspi_4.buster.img 
of=/media/dave/3339-3839/rpi_4_buster

unmount
put SD in rpi4B and power up
get the same error  messages as before:

autoboot.txt not found
config.txt not found
recover4.elf not found
recovery.elf not found
start.elf not found
SD boot failed

So is the .img missing bits and pieces or are there steps beyond the dd 
of the image that need to

add the missing files?  If so where do I look for these files?

Dave


On 4/6/21 4:47 PM, andy pugh wrote:

On Tue, 6 Apr 2021 at 22:56, Feral Engineer  wrote:


Have you experienced crashes in lcnc on a pi4b?

TBH I haven't really used it. I have lots of other LinuxCNC machines
which actually have monitors.





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[Emc-users] Rpi4B OS

[dave engvall]

Hi,
After much fuss due to a bad assumption I made I finally managed to 
flash the 7i90 for spi. Easy when you do it right.


However, loading an OS isn't going well:
Download a buster image as a .zip. Unpack to get an .img.
dd .img to 32G SD, stick in slot and power up.
I get 4 blinks ( no elf ) and messages on screen that complain about no 
bootxx.txt and elf and elf4 missing.
So I asking for help. I think I need a 7l kernel and uspace. 
Instructions styled for a dummy (I don't seem to be
getting any smarter with age) should move this along.  That is what to 
download and then move it to a 32G SD.

I've  spent way too much time spinning my wheels in the mud.
TIA.

Dave


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Re: [Emc-users] Spindle rps and index

[dave engvall]

My Mazak V5 had a coarse helix cam which oriented the spindle. The one 
at Galesburg used something closer to  an  inductive sensor to sense 
index.. I think that got swapped out for an encoder. Once it picked up 
the index it then rotated n counts to index the spindle for tool 
change.  If memory serves the spindle did  a dampened oscillation to get 
to position.


Dave

On 3/18/21 8:10 PM, John Dammeyer wrote:



-Original Message-
From: Jon Elson [mailto:el...@pico-systems.com]

Interesting topic.

I take it then that you can't actually move the spindle to the index position 
unless you have some sort of control beyond velocity?

I'm currently using PWM on mine but once I redo some wiring I can run it with 
step/dir.  So theoretically it should be possible to

move to a 'home' or '0.000' position.  But how is that even done if the spindle 
is controlled with M3,M4 and Sxxx?



You have to put some kind of custom component in between.
The problem is you now want to
have a thing which switches back and forth between a spindle
(M3, 4 and 5 and Sxxx) and an axis C.  You have to give some
kind of command with a custom M code that disconnects it as
an axis and connects it as a spindle, and then reverses the
process, all without causing a following error.
It could be a bit tricky.  This has come up a number of
times in the past.

Jon

Not having one of those keyed tool changers or for that matter a HAAS to play 
with I'm partly in the dark here.  If your mill has one of those BT-30 to BT-50 
type holders with the two slots on the side do they not need to lock into the 
spindle?

Done by hand I guess a human just rotates it until it slips the rest of the way 
in.

Is the machine told turn 1 RPM while the tool changer presses the tool up so it 
latches into the slot?  Or do the fancy machines have an index to which they 
locate so the tool automatically latches in with the correct orientation?

Thanks
John




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Re: [Emc-users] Probe recommendations.

[dave engvall]

I suspect Belarus.

On 3/14/21 10:09 AM, Gene Heskett wrote:

On Sunday 14 March 2021 06:34:04 andy pugh wrote:


On Sun, 14 Mar 2021 at 10:07, Gene Heskett 

wrote:

https://vers.by/en/touch-probes/9-vers-pr.html

What is this in USD?

It says "355.00 BYN~  10050 RUB,   136 USD,   113 EUR"

I went to the web site, very sparse with its data, but that is a decent
enough price, that I wonder what the shipping may be, and from where?

Thanks Andy.

Cheers, Gene Heskett




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Re: [Emc-users] Nice camera/probe integration

[dave engvall]

I rather hate to think of the cost ... beautiful stuff ... German made.
It is easy to make a probe; good software to extract the real value of 
the probe, not so easy.


Dave

On 3/12/21 9:14 AM, Ralph Stirling wrote:

This would be an awesome setup for Linuxcnc.

https://www.datron.com/revolutionize-workpiece-setup/

-- Ralph

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[Emc-users] Rpi4B_7i90

[dave engvall]

Hi all,
I'm trying to get an Rpi4b -> 7i90 going.

Ralph Stirling made an interface board for the pi that allows one to 
flash the spi.


The following is copy of the procedure:


On Rpi:

$ git clone git://git.code.sf.net/p/openocd/code openocd
$ cd openocd
$ ./bootstrap
$ ./configure --enable-maintainer-mode --enable-bcm2835gpio 
--enable-sysfsgpio

$ make -j4
$ sudo make install

Go into Raspbian Setup from the application menu, and turn off SPI 
device driver.  Openocd has a builtin driver.


Use the openocd_rpi.sh script to load bitstreams via jtag
into the FPGA itself. This is not permanent, so you need
to follow this with mesaflash to put it in the EEPROM.

$openocd_rpi.sh whatever_spi_bitstream.bit

Now go back in to Raspbian Setup and turn on the SPI driver. You can now 
use mesaflash to flash the EEPROM.


$ sudo mesaflash --device 7i90 --addr /dev/spidev0.0 --spi --write 
whatever_spi_bitstream.bit


I don't recall whether SPI needs to be enabled or disabled
after this for hostmot2 to run in linuxcnc, but it is easy
enough to try each way.

Ha! Not quite.

Google gives hits but none of them go deep enough to fix my problems.

Clearly this is set up for bcm2835 eg. Rpi3b however just editing the 
bcm numbers to Rpi4b 2711 doesn't work.

Deeper changes are clearly needed.
Can anyone supply the relevant files for bcm2711?

Comments and guidance appreciated.

Dave

file: rpi_jtag.cfg
interface bcm2835gpio
bcm2835gpio_peripheral_base 0x3F00

# Transition delay calculation: SPEED_COEFF/khz - SPEED_OFFSET
# These depend on system clock, calibrated for stock 700MHz
# bcm2835gpio_speed SPEED_COEFF SPEED_OFFSET
bcm2835gpio_speed_coeffs 146203 36

# Each of the JTAG lines need a gpio number set: tck tms tdi tdo
## Header pin numbers: 23 22 19 21
#bcm2835gpio_jtag_nums 11 25 10 9
# Header pin numbers: 11 13 15 29
bcm2835gpio_jtag_nums 17 27 22 5



file: openocd_rpi.sh
#!/bin/bash

openocd \
    -f /usr/local/share/openocd/scripts/interface/rpi_jtag.cfg \
    -f /usr/local/share/openocd/scripts/cpld/xilinx-xc6s.cfg \
    -c "adapter driver rpi_jtag ; adapter speed 500; init; \
    xc6s_program xc6s.tap; pld load 0 $1 ; exit"

Stick that in a file, chmod +x it and see if it works!





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Re: [Emc-users] isolcpus?

[dave engvall]

The few  times I've had different counts re' direction it has been a 
broken flex coupling to the encoder.
Of course it could be that you are simply running out of frequency 
response. Not likely but possible.


Dave

On 3/7/21 12:54 PM, Gene Heskett wrote:

On Sunday 07 March 2021 14:07:33 Feral Engineer wrote:
[...]

sudo update-grub

Wasn't in there, put it in and rebooted.

Now I am re-calibrating the servo_scale which will take an hour or more.
I snapshot the encoder count at 1.0 turns of the home-switch, snapshot
the counter at 101 turns, subtract the first count from the second to
get the diff, div that by 100 to get 1 turn, and divide by 360 to get
one degree.  Or just div by 36000. I am also suspecting I'm missing a
count, at g0 speed, 1800 degrees a minute, the dro is losing counts,
worse in one dir than the other. I *think* that's a separate problem.

Thanks Phil T.  Stay safe and well.

Cheers, Gene Heskett




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Re: [Emc-users] Fiber laser power requirements - any experience out there?

[dave engvall]

https://www.toolots.com/quality-ezcad-jpt-30w-fiber-laser-engraver-marking-machine-for-metal.html?cid=10310162125=EAIaIQobChMIkY-kjNaU7wIVEz2tBh35iAhYEAQYBCABEgJiv_D_BwE

Others seem to use more power; like 80 to 100 w but not necessarily FO.

Dave

On 3/3/21 9:34 AM, Curtis Dutton wrote:

I have an ongoing job engraving stainless steel plaques that are at most
4.5" square. Currently we are doing them in the CNC router. Very simple
markings just digits and letters. Engraved to about a depth of 10 to 15
thousands of an inch with a spot drill.

This is becoming a fairly regular job and I'm thinking about building a
dedicated machine for it. I could build a very little simple milling type
machine but I'd like to consider a fiber laser for doing it.

It looks like there are some machines that could perform the engraving but
I'm not sure what sort of wattage level would be appropriate. Obviously the
more power, the faster it can engrave but how much would be adequate and
how much power would be overkill.

Does anyone have any resource or recommendations about fiber lasers? I use
a CO2 laser daily for engraving wood, but I have never been around a fiber
laser.


Thanks,
Curt

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