Re: [Emc-users] FERROR MIN_FERROR value?

[Gene Heskett]

On Thursday 28 May 2020 02:08:46 Thaddeus Waldner wrote:

> Here’s one that I have used successfully:
>
> https://www.thingiverse.com/thing:16627
>
> It is a parametric pulley designed in OpenScad.  I believe the
> Thingiverse website allows you to configure openscad designs from the
> website, then download the.stl. But you can also download the Openscad
> file.
>
> .stl is what your slicer (CAM for 3d printers) wants.
>
> For a reliable motor-mounted pulley, I ended up doing something
> similar to what Chris Albertson describes. Mine was a plastic pulley
> with a hub that has two pockets for clamp nuts. The OD of this hub
> fits snugly into a metal ring with a pair of radial holes. The set
> screws run through these holes, thread into the nuts, then bite into
> the motor shaft.

That looks like it fits the description I had in mind, when I get it 
setup, I'll open an account, thank you, Thaddeus Waldner.

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] FERROR MIN_FERROR value?

[Gregg Eshelman via Emc-users]

Use half a shaft coupler as a hub for attaching a 3D printed part to a shaft. 
https://hackaday.com/2019/09/02/misuse-this-part-to-attach-3d-printed-stuff-to-a-shaft/
 

On Thursday, May 28, 2020, 12:11:32 AM MDT, Thaddeus Waldner 
 wrote:  
 
 Here’s one that I have used successfully:

https://www.thingiverse.com/thing:16627

It is a parametric pulley designed in OpenScad.  I believe the Thingiverse 
website allows you to configure openscad designs from the website, then 
download the.stl. But you can also download the Openscad file.

.stl is what your slicer (CAM for 3d printers) wants.

For a reliable motor-mounted pulley, I ended up doing something similar to what 
Chris Albertson describes. Mine was a plastic pulley with a hub that has two 
pockets for clamp nuts. The OD of this hub fits snugly into a metal ring with a 
pair of radial holes. The set screws run through these holes, thread into the 
nuts, then bite into the motor shaft.  
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Re: [Emc-users] FERROR MIN_FERROR value?

[Chris Albertson]

Yes, the better one is better, especially when you want to move to AB or
other plastic types.   Some people like to print on glass. I use aluminum
bed at 60 C coated with glue stick glue.   Glass with hair spray works and
blue painters tape.   Everyone developes their own prefferce.

As for software...

You really need some 3D CAD software or else  you can only print things
others have made.  Not a bad why to start. but you eventually want to peint
your own designs.  I like Fusion 360.  Others like other things.But
one thig abut Fusion s that it can drive a milling machine or lathe.  You
can print of mill the same 3D model.  Fusion will figure out tool paths as
well as save to files that can be printed.

So you either download an STL file from Thiniverse or make a STL file using
fusion360 (or sketchup or freecad or...)


Then you run a slicer app.  I like Cura but others will like "Slic3r".
Both are open source.   Both accept an STL and then you set 100 parameters
and they creat g-code. Don't even bother to look at the g-code.  It
might have literally one million lines of code and control 4 axis, 2
heaters and some fans

You can expect about 3 weeks of frustration because nothing will work, then
it will.

After a while you start thinging about parts design diferently because now
3D compound curves with an organicshape are easy to make.  Think of a
cordless drill case with an external round shape and interior made to hold
al the parts.   that ould be way-hold to make on a mill bu is a good
student project using fusion and a printer.  One of the tutorial walks you
through making a "saz-all"


> I wound up buying the higher priced version to get the better bed, some
> extra nozzles and a couple rolls of PLA.  Obviously I need driver sw, so
> will need some tutoring on that.  For instance, and using my experience
> at writing gcode, is there a timing pulley pattern for 2mm timing belts
> that autosizes the product according to the requested number teeth, and
> allows an adjustable center hole for attaching it to a metal hub? plus
> flanges of course. I've made several taper lock hubs that have worked
> well including a repair of the lower 2 belt pulley in the E400 under
> drive of my Sheldon 11x54 lathe.
>
> > The plastic costs about $22 per Kg.  I use "hatchbox" band but I'm
> > sure others work too.  Just do start with PLA and likely you stay with
> > it. amazon.com/HATCHBOX
> >  >00J0GPC80/ref=pd_sim_328_5/140-9661733-2175833?_encoding=UTF8_rd_i=B
> >00J0GPC80_rd_r=c9f25db5-27c5-4c4e-b5fb-62dd9b9c3b12_rd_w=5vegT
> >_rd_wg=AfyjI_rd_p=6f740e39-0c25-4380-8008-7a4156dab959_rd_r=W6FB1
> >TGW7SX8KDWJ04KR=1=W6FB1TGW7SX8KDWJ04KR> 1 Kg is a lot.   I
> > printed a mod 2, 120 tooth gear that is about 5" diameter and 1" face
> > width.  It is a really big gear. It used about 160g of plastic.
> >
> I couldn't find hatchbox brand at that link so I paid a couple bucks
> more, all PLA. It should all be here next week.  Hopefully I can make
> all the timing pulleys needed to run a BS-1 clone.  Still have to buy
> belts though.  S/B 4 pulleys all together as I'll have to make an on
> tilt axis center intermediate shaft in order to use the tilt feature w/o
> needing a grocery sack of belts.  That should also get me geared down to
> where that 3NM motor can run it under cutting forces. And it might do
> the motor mounts, grabbing both ends of the motor.
>
> > > > On Wed, May 27, 2020 at 2:06 PM Gene Heskett
> > > > 
> > >
> > > wrote:
> > > > > On Wednesday 27 May 2020 00:51:57 Gene Heskett wrote:
> > > > > > On Tuesday 26 May 2020 19:45:10 Chris Albertson wrote:
> > > > > > > On Tue, May 26, 2020 at 3:01 PM Gene Heskett
> > > > > > > 
> > > > > >
> > > > > > wrote:
> > > > > > > > Those closed loop motors and controllers have arrived, and
> > > > > > > > I puzzled by a total lack of docs other than the u-step
> > > > > > > > ratios printed on the cover. Thats covered by dip sw1-4,
> > > > > > > > but its a 6 pos switch, and 5 & 6 are in Chinese
> > > > > > > > pictograms.
> > > > > > >
> > > > > > > I'm following this because, as said, I plan on doing the
> > > > > > > same. However I always read the docs BEFORE buying, no docs,
> > > > > > > I don't buy.
> > > > > > >
> > > > > > > Post a photo of the Chinese characaters,  I have someone
> > > > > > > here fluent in Chinese.  Also you can try Chinese OCR and
> > > > > > > then apply Google Translate.
> > > > > > > http://www.i2ocr.com/free-online-chinese-traditional-ocr
> > > > > >
> > > > > > I found out what they do, one is a direction reverser, the
> > > > > > other makes it open loop.  Suits me anyway. I'll get one of
> > > > > > those supplies and one of these on the same table and play
> > > > > > with a function generator tomorrow, claims to be good for 200
> > > > > > khz steps, and has divisors out the yang, so it ought to be a
> > > > > > dropin except for the mounts and shaft 

Re: [Emc-users] FERROR MIN_FERROR value?

[Chris Albertson]

To find a well-designed timing pulley, go to any web site that sells
pulleys. SPD/SI is one of the best.Then find the pulley or gear you
would like and there will be a link to download a CAD file for that exact
gear/pulley.  McMaster Carr also has CAD files for all their stuff. So dose
Boston Gear.

Here is an example page:
http://shop.sdp-si.com/catalog/?cid=p346=a0%3A2%3A3%20mm%20(GT2)%3Ba15%3A2%3A2%20Flanges%2FWith%20Hub%3ANo%20Flange%2FWith%20Hub=undefined=table

Notice the "CAD" link.   From there you can drill down to the actual file.
  This CAD model will be of the actual part that you can buy.  Download the
file then import the file.  Almost certainly you will need to modify the
bore to fit your motor.   I like to cut a 20mm hole and fit them over a
20mm steel bushing.  But you can made a 9mm "D" or keyway or what ever the
motor has.  Then save to STL and put itthough your slicer to make g-code.
  It is a long workflow

The eniter SPD/SI inventory is available to download.  Although as said,
printed belts don't work well.


On Wed, May 27, 2020 at 11:11 PM Thaddeus Waldner 
wrote:

> Here’s one that I have used successfully:
>
> https://www.thingiverse.com/thing:16627
>
> It is a parametric pulley designed in OpenScad.  I believe the Thingiverse
> website allows you to configure openscad designs from the website, then
> download the.stl. But you can also download the Openscad file.
>
> .stl is what your slicer (CAM for 3d printers) wants.
>
> For a reliable motor-mounted pulley, I ended up doing something similar to
> what Chris Albertson describes. Mine was a plastic pulley with a hub that
> has two pockets for clamp nuts. The OD of this hub fits snugly into a metal
> ring with a pair of radial holes. The set screws run through these holes,
> thread into the nuts, then bite into the motor shaft.
>
>
> Sent from my iPhone
>
> > On May 28, 2020, at 12:30 AM, Gene Heskett  wrote:
> >
> > On Wednesday 27 May 2020 23:23:39 Chris Albertson wrote:
> >
> >> On Wed, May 27, 2020 at 5:38 PM Gene Heskett 
> > wrote:
>  On Wednesday 27 May 2020 20:10:44 Chris Albertson wrote:
> > By total coincidence, I just made both.  I needed 30T, 40T, and
> > 60T pulleys.   I tried printing them and they fail after a while.
> > The plastic simply will not hold the set screw then they slip on
> > the shaft.  The big thing is if the motor gets warm it heats the
> > plastic. The solution has to print the pulley as the thin ring. My
> > 30T puley has a 20mm hole.  Then use the lathe to make a 20mm OD
> > bushing with two set screws 90 degrees apart. I make this with
> > steel.  The pulley-ring is press fit to the steel bushing using 5
> > minute epoxy. OK, you ask "How strong can plastic teeth be?" the
> > answer seems to be "stronger than the rubber teeth on the belt."
> > The part of the pulley that needs to be strong is the hub and that
> > is now steel. Making a center bored cylindrical bushing is a very
> > easy job.   I made a few and this method turned out the simplest
> > and best.   Make the ring really thin so as to make the bushing as
> > big as you can.
> >
> > I just returned from riding my bike for a few hours and notice my
> > NEMA23 mount plate is 80% finished.   I'm still testing if these
> > can be made with plastic.  I think so if about 6mm thick   I'll
> > know soon. I have a test setup to check for flex in the plate.
> >
> > I'm working on a plan or "kit" to convert an HF mill to CNC using
> > way-cheap plastic parts (< $20 material cost) and minimal machine
> > work.   I'll publish the design files after it works.I've had
> > to redesign/remake some parts 3 or 4 times but it comes out more
> > simple each iteration
> >>>
> >>> I'd like to see if I could convert this 6040 into a printer,
> >>> precisely so I could do something along those lines but in looking
> >>> around for a printhead, it seems the drive is much lighter so
> >>> smaller motors can move it faster, and never the twain shall meet.
> >>> Trading a 3kg 24k spindle motor out for a printhead the might weigh
> >>> 5oz is quite a change.  I could buy another printer, but where I'd
> >>> have to set it up has no AC. And good results seem to be quite temp
> >>> dependent.  So I get that stuff from fleabay, and wait, and wait,
> >>> and wait.  Thats frustrating too.
> >>>
> >>> So who makes the best printer for stuff like this, at an affordable
> >>> price?
> >>
> >> Most people are recommending the "Ender" brand printer for your
> >> use-case. This is an open-source design that uses industry-standard
> >> parts so future maintenance should not be to much of an issue. If
> >> you print with PLA plastic, it is bomb-proof simple and temperature,
> >> and so on does not matter.  My printer is an Anet "A6" and I paid
> >> about $185 for it.  It looks cheap because the frame is made from
> >> laser-cut acrylic plastic.  But acrylic 

Re: [Emc-users] FERROR MIN_FERROR value?

[Gregg Eshelman via Emc-users]

One key to good FDM printing is a steady ambient temperature *with no airflow* 
around the printer. A bit of a breeze can cause uneven shrinkage and warping. 
That's why some printers are enclosed and building a printer enclosure is a 
popular thing.

If you're wanting to get your 3D printing feet wet, easily and inexpensively, 
the Monoprice Select Mini V2 is $219.99. It comes fully assembled, take it out 
of the box, level the bed, it's ready to use. Mostly steel construction, weighs 
around 16 pounds. With the original version a Facebook group was founded, they 
stopped counting members when it hit 5,000. Owners of all Monoprice 3D printers 
are welcomed, lots of them have upgraded from the mini.
My Mini has made me $$$. One job I did with it made me $500. :) I used it to 
print some knobs for a classic car. Filled the shells with urethane resin, with 
jigs I 3D printed to hold rods (and a 3/8-16 bolt for the shift knob) upright 
to make starter holes for mounting in the resin. I also printed vise jigs to 
clamp the knobs for drilling the holes to size. Sent along a few extra knobs to 
the restoration shop to experiment on finishing the outside.

I forget which car they were for but some fancy classic exhibited at Hershey 
and other Concours d'Elegance shows had my 3D printed knobs. :) I have a larger 
Hictop printer I bought for $100 but have yet to use it. Before I bought the 
mini I bought a kit of all the electronics to build a printer but have yet to 
get around to building the frame.

On Wednesday, May 27, 2020, 6:38:35 PM MDT, Gene Heskett 
 wrote:  
I'd like to see if I could convert this 6040 into a printer, precisely so 
I could do something along those lines but in looking around for a 
printhead, it seems the drive is much lighter so smaller motors can move 
it faster, and never the twain shall meet. Trading a 3kg 24k spindle 
motor out for a printhead the might weigh 5oz is quite a change.  I 
could buy another printer, but where I'd have to set it up has no AC. 
And good results seem to be quite temp dependent.  So I get that stuff 
from fleabay, and wait, and wait, and wait.  Thats frustrating too.

So who makes the best printer for stuff like this, at an affordable 
price?  
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Re: [Emc-users] FERROR MIN_FERROR value?

[Ralph Stirling]

I often incorporate a slot inside the gear or
pulley (like a keyway) the width of a nut.
Slip a nut down the slot and screw the set
screw into the nut through a radial hole.  Now 
the force is between the nut face and the 
plastic part (compression) rather than on 
fragile threads in the plastic.

-- Ralph

From: andy pugh [bodge...@gmail.com]
Sent: Wednesday, May 27, 2020 6:21 PM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] FERROR MIN_FERROR value?

CAUTION: This email originated from outside the Walla Walla University email 
system.


On Thu, 28 May 2020 at 01:13, Chris Albertson  wrote:

> By total coincidence, I just made both.  I needed 30T, 40T, and 60T
> pulleys.   I tried printing them and they fail after a while.  The plastic
> simply will not hold the set screw then they slip on the shaft.

There was an interesting solution to this on Hackaday a while back:

https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fhackaday.com%2F2019%2F09%2F02%2Fmisuse-this-part-to-attach-3d-printed-stuff-to-a-shaft%2Fdata=02%7C01%7Cralph.stirling%40wallawalla.edu%7C02de9b609b9b498e7b4508d802a587de%7Cd958f048e43142779c8debfb75e7aa64%7C0%7C0%7C637262257266623247sdata=qvWd3EZgslDbfuG%2FV0drXHQ4gcygHBIGL50GhDaClgU%3Dreserved=0


--
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] FERROR MIN_FERROR value?

[Thaddeus Waldner]

Here’s one that I have used successfully:

https://www.thingiverse.com/thing:16627

It is a parametric pulley designed in OpenScad.  I believe the Thingiverse 
website allows you to configure openscad designs from the website, then 
download the.stl. But you can also download the Openscad file.

.stl is what your slicer (CAM for 3d printers) wants.

For a reliable motor-mounted pulley, I ended up doing something similar to what 
Chris Albertson describes. Mine was a plastic pulley with a hub that has two 
pockets for clamp nuts. The OD of this hub fits snugly into a metal ring with a 
pair of radial holes. The set screws run through these holes, thread into the 
nuts, then bite into the motor shaft.


Sent from my iPhone

> On May 28, 2020, at 12:30 AM, Gene Heskett  wrote:
> 
> On Wednesday 27 May 2020 23:23:39 Chris Albertson wrote:
> 
>> On Wed, May 27, 2020 at 5:38 PM Gene Heskett  
> wrote:
 On Wednesday 27 May 2020 20:10:44 Chris Albertson wrote:
> By total coincidence, I just made both.  I needed 30T, 40T, and
> 60T pulleys.   I tried printing them and they fail after a while. 
> The plastic simply will not hold the set screw then they slip on
> the shaft.  The big thing is if the motor gets warm it heats the
> plastic. The solution has to print the pulley as the thin ring. My
> 30T puley has a 20mm hole.  Then use the lathe to make a 20mm OD
> bushing with two set screws 90 degrees apart. I make this with
> steel.  The pulley-ring is press fit to the steel bushing using 5
> minute epoxy. OK, you ask "How strong can plastic teeth be?" the
> answer seems to be "stronger than the rubber teeth on the belt." 
> The part of the pulley that needs to be strong is the hub and that
> is now steel. Making a center bored cylindrical bushing is a very
> easy job.   I made a few and this method turned out the simplest
> and best.   Make the ring really thin so as to make the bushing as
> big as you can.
> 
> I just returned from riding my bike for a few hours and notice my
> NEMA23 mount plate is 80% finished.   I'm still testing if these
> can be made with plastic.  I think so if about 6mm thick   I'll
> know soon. I have a test setup to check for flex in the plate.
> 
> I'm working on a plan or "kit" to convert an HF mill to CNC using
> way-cheap plastic parts (< $20 material cost) and minimal machine
> work.   I'll publish the design files after it works.I've had
> to redesign/remake some parts 3 or 4 times but it comes out more
> simple each iteration
>>> 
>>> I'd like to see if I could convert this 6040 into a printer,
>>> precisely so I could do something along those lines but in looking
>>> around for a printhead, it seems the drive is much lighter so
>>> smaller motors can move it faster, and never the twain shall meet.
>>> Trading a 3kg 24k spindle motor out for a printhead the might weigh
>>> 5oz is quite a change.  I could buy another printer, but where I'd
>>> have to set it up has no AC. And good results seem to be quite temp
>>> dependent.  So I get that stuff from fleabay, and wait, and wait,
>>> and wait.  Thats frustrating too.
>>> 
>>> So who makes the best printer for stuff like this, at an affordable
>>> price?
>> 
>> Most people are recommending the "Ender" brand printer for your
>> use-case. This is an open-source design that uses industry-standard
>> parts so future maintenance should not be to much of an issue. If
>> you print with PLA plastic, it is bomb-proof simple and temperature,
>> and so on does not matter.  My printer is an Anet "A6" and I paid
>> about $185 for it.  It looks cheap because the frame is made from
>> laser-cut acrylic plastic.  But acrylic is strong and rigid and works
>> well.   The Ender has a metal frame and is slighter better.
>> 
>> But be-warned, a printer is like a CNC mill in that that parts it
>> makes have to be carefully designed but unlike a mill, there is no
>> hope of ever writing printer G-code by hand, it is far to complex.   
>> Plastic can be strong if you puff up the thickness and make all the
>> sides round.   You tend to print parts with solid shell and a
>> foam-like interior.
>> 
>> amazon.com/Comgrow-Creality-Ender-Aluminum
>> > dp/B07BR3F9N6>
>> 
>> This is the one I have.   The price has gone up because those selling
>> cheap when broke.
>> amazon.com/Precision-Desktop-Printer
>> > /B01N5XV5NU/ref=sr_1_2?dchild=1=anet+a6+printer=1590632711
>> =industrial=1-2>
>> 
> I wound up buying the higher priced version to get the better bed, some 
> extra nozzles and a couple rolls of PLA.  Obviously I need driver sw, so 
> will need some tutoring on that.  For instance, and using my experience 
> at writing gcode, is there a timing pulley pattern for 2mm timing belts 
> that autosizes the 

Re: [Emc-users] FERROR MIN_FERROR value?

[Gene Heskett]

On Wednesday 27 May 2020 23:23:39 Chris Albertson wrote:

> On Wed, May 27, 2020 at 5:38 PM Gene Heskett  
wrote:
> > On Wednesday 27 May 2020 20:10:44 Chris Albertson wrote:
> > > By total coincidence, I just made both.  I needed 30T, 40T, and
> > > 60T pulleys.   I tried printing them and they fail after a while. 
> > > The plastic simply will not hold the set screw then they slip on
> > > the shaft.  The big thing is if the motor gets warm it heats the
> > > plastic. The solution has to print the pulley as the thin ring. My
> > > 30T puley has a 20mm hole.  Then use the lathe to make a 20mm OD
> > > bushing with two set screws 90 degrees apart. I make this with
> > > steel.  The pulley-ring is press fit to the steel bushing using 5
> > > minute epoxy. OK, you ask "How strong can plastic teeth be?" the
> > > answer seems to be "stronger than the rubber teeth on the belt." 
> > > The part of the pulley that needs to be strong is the hub and that
> > > is now steel. Making a center bored cylindrical bushing is a very
> > > easy job.   I made a few and this method turned out the simplest
> > > and best.   Make the ring really thin so as to make the bushing as
> > > big as you can.
> > >
> > > I just returned from riding my bike for a few hours and notice my
> > > NEMA23 mount plate is 80% finished.   I'm still testing if these
> > > can be made with plastic.  I think so if about 6mm thick   I'll
> > > know soon. I have a test setup to check for flex in the plate.
> > >
> > > I'm working on a plan or "kit" to convert an HF mill to CNC using
> > > way-cheap plastic parts (< $20 material cost) and minimal machine
> > > work.   I'll publish the design files after it works.I've had
> > > to redesign/remake some parts 3 or 4 times but it comes out more
> > > simple each iteration
> >
> > I'd like to see if I could convert this 6040 into a printer,
> > precisely so I could do something along those lines but in looking
> > around for a printhead, it seems the drive is much lighter so
> > smaller motors can move it faster, and never the twain shall meet.
> > Trading a 3kg 24k spindle motor out for a printhead the might weigh
> > 5oz is quite a change.  I could buy another printer, but where I'd
> > have to set it up has no AC. And good results seem to be quite temp
> > dependent.  So I get that stuff from fleabay, and wait, and wait,
> > and wait.  Thats frustrating too.
> >
> > So who makes the best printer for stuff like this, at an affordable
> > price?
>
> Most people are recommending the "Ender" brand printer for your
> use-case. This is an open-source design that uses industry-standard
> parts so future maintenance should not be to much of an issue. If
> you print with PLA plastic, it is bomb-proof simple and temperature,
> and so on does not matter.  My printer is an Anet "A6" and I paid
> about $185 for it.  It looks cheap because the frame is made from
> laser-cut acrylic plastic.  But acrylic is strong and rigid and works
> well.   The Ender has a metal frame and is slighter better.
>
> But be-warned, a printer is like a CNC mill in that that parts it
> makes have to be carefully designed but unlike a mill, there is no
> hope of ever writing printer G-code by hand, it is far to complex.   
> Plastic can be strong if you puff up the thickness and make all the
> sides round.   You tend to print parts with solid shell and a
> foam-like interior.
>
> amazon.com/Comgrow-Creality-Ender-Aluminum
> dp/B07BR3F9N6>
>
> This is the one I have.   The price has gone up because those selling
> cheap when broke.
> amazon.com/Precision-Desktop-Printer
> /B01N5XV5NU/ref=sr_1_2?dchild=1=anet+a6+printer=1590632711
>=industrial=1-2>
>
I wound up buying the higher priced version to get the better bed, some 
extra nozzles and a couple rolls of PLA.  Obviously I need driver sw, so 
will need some tutoring on that.  For instance, and using my experience 
at writing gcode, is there a timing pulley pattern for 2mm timing belts 
that autosizes the product according to the requested number teeth, and 
allows an adjustable center hole for attaching it to a metal hub? plus 
flanges of course. I've made several taper lock hubs that have worked 
well including a repair of the lower 2 belt pulley in the E400 under 
drive of my Sheldon 11x54 lathe.

> The plastic costs about $22 per Kg.  I use "hatchbox" band but I'm
> sure others work too.  Just do start with PLA and likely you stay with
> it. amazon.com/HATCHBOX
> 00J0GPC80/ref=pd_sim_328_5/140-9661733-2175833?_encoding=UTF8_rd_i=B
>00J0GPC80_rd_r=c9f25db5-27c5-4c4e-b5fb-62dd9b9c3b12_rd_w=5vegT
>_rd_wg=AfyjI_rd_p=6f740e39-0c25-4380-8008-7a4156dab959_rd_r=W6FB1
>TGW7SX8KDWJ04KR=1=W6FB1TGW7SX8KDWJ04KR> 1 Kg is a lot.   I
> printed a mod 2, 120 tooth gear that is about 

Re: [Emc-users] FERROR MIN_FERROR value?

[Chris Albertson]

On Wed, May 27, 2020 at 5:38 PM Gene Heskett  wrote:

> On Wednesday 27 May 2020 20:10:44 Chris Albertson wrote:
>
> > By total coincidence, I just made both.  I needed 30T, 40T, and 60T
> > pulleys.   I tried printing them and they fail after a while.  The
> > plastic simply will not hold the set screw then they slip on the
> > shaft.  The big thing is if the motor gets warm it heats the plastic.
> > The solution has to print the pulley as the thin ring. My 30T puley
> > has a 20mm hole.  Then use the lathe to make a 20mm OD bushing with
> > two set screws 90 degrees apart. I make this with steel.  The
> > pulley-ring is press fit to the steel bushing using 5 minute epoxy.
> > OK, you ask "How strong can plastic teeth be?" the answer seems to be
> > "stronger than the rubber teeth on the belt."  The part of the pulley
> > that needs to be strong is the hub and that is now steel. Making a
> > center bored cylindrical bushing is a very easy job.   I made a few
> > and this method turned out the simplest and best.   Make the ring
> > really thin so as to make the bushing as big as you can.
> >
> > I just returned from riding my bike for a few hours and notice my
> > NEMA23 mount plate is 80% finished.   I'm still testing if these can
> > be made with plastic.  I think so if about 6mm thick   I'll know soon.
> >  I have a test setup to check for flex in the plate.
> >
> > I'm working on a plan or "kit" to convert an HF mill to CNC using
> > way-cheap plastic parts (< $20 material cost) and minimal machine
> > work.   I'll publish the design files after it works.I've had to
> > redesign/remake some parts 3 or 4 times but it comes out more simple
> > each iteration
>
> I'd like to see if I could convert this 6040 into a printer, precisely so
> I could do something along those lines but in looking around for a
> printhead, it seems the drive is much lighter so smaller motors can move
> it faster, and never the twain shall meet. Trading a 3kg 24k spindle
> motor out for a printhead the might weigh 5oz is quite a change.  I
> could buy another printer, but where I'd have to set it up has no AC.
> And good results seem to be quite temp dependent.  So I get that stuff
> from fleabay, and wait, and wait, and wait.  Thats frustrating too.
>
> So who makes the best printer for stuff like this, at an affordable
> price?
>

Most people are recommending the "Ender" brand printer for your use-case.
This is an open-source design that uses industry-standard parts so
future maintenance should not be to much of an issue. If you print with
PLA plastic, it is bomb-proof simple and temperature, and so on does not
matter.  My printer is an Anet "A6" and I paid about $185 for it.  It looks
cheap because the frame is made from laser-cut acrylic plastic.  But
acrylic is strong and rigid and works well.   The Ender has a metal frame
and is slighter better.

But be-warned, a printer is like a CNC mill in that that parts it makes
have to be carefully designed but unlike a mill, there is no hope of ever
writing printer G-code by hand, it is far to complex.Plastic can be
strong if you puff up the thickness and make all the sides round.   You
tend to print parts with solid shell and a foam-like interior.

amazon.com/Comgrow-Creality-Ender-Aluminum


This is the one I have.   The price has gone up because those selling cheap
when broke.
amazon.com/Precision-Desktop-Printer


The plastic costs about $22 per Kg.  I use "hatchbox" band but I'm sure
others work too.  Just do start with PLA and likely you stay with it.
amazon.com/HATCHBOX

 1 Kg is a lot.   I printed a mod 2, 120 tooth gear that is about 5"
diameter and 1" face width.  It is a really big gear. It used about 160g of
plastic.



> > On Wed, May 27, 2020 at 2:06 PM Gene Heskett 
> wrote:
> > > On Wednesday 27 May 2020 00:51:57 Gene Heskett wrote:
> > > > On Tuesday 26 May 2020 19:45:10 Chris Albertson wrote:
> > > > > On Tue, May 26, 2020 at 3:01 PM Gene Heskett
> > > > > 
> > > >
> > > > wrote:
> > > > > > Those closed loop motors and controllers have arrived, and I
> > > > > > puzzled by a total lack of docs other than the u-step ratios
> > > > > > printed on the cover. Thats covered by dip sw1-4, but its a 6
> > > > > > pos switch, and 5 & 6 are in Chinese pictograms.
> > > > >
> > > > > I'm following this because, as said, I plan on doing the same.
> > > > > However I always read the docs BEFORE buying, no docs, I don't
> > > > > buy.
> > > > 

Re: [Emc-users] FERROR MIN_FERROR value?

[andy pugh]

On Thu, 28 May 2020 at 01:13, Chris Albertson  wrote:

> By total coincidence, I just made both.  I needed 30T, 40T, and 60T
> pulleys.   I tried printing them and they fail after a while.  The plastic
> simply will not hold the set screw then they slip on the shaft.

There was an interesting solution to this on Hackaday a while back:

https://hackaday.com/2019/09/02/misuse-this-part-to-attach-3d-printed-stuff-to-a-shaft/


-- 
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] FERROR MIN_FERROR value?

[Gene Heskett]

On Wednesday 27 May 2020 20:10:44 Chris Albertson wrote:

> By total coincidence, I just made both.  I needed 30T, 40T, and 60T
> pulleys.   I tried printing them and they fail after a while.  The
> plastic simply will not hold the set screw then they slip on the
> shaft.  The big thing is if the motor gets warm it heats the plastic. 
> The solution has to print the pulley as the thin ring. My 30T puley
> has a 20mm hole.  Then use the lathe to make a 20mm OD bushing with
> two set screws 90 degrees apart. I make this with steel.  The
> pulley-ring is press fit to the steel bushing using 5 minute epoxy.  
> OK, you ask "How strong can plastic teeth be?" the answer seems to be
> "stronger than the rubber teeth on the belt."  The part of the pulley
> that needs to be strong is the hub and that is now steel. Making a
> center bored cylindrical bushing is a very easy job.   I made a few
> and this method turned out the simplest and best.   Make the ring
> really thin so as to make the bushing as big as you can.
>
> I just returned from riding my bike for a few hours and notice my
> NEMA23 mount plate is 80% finished.   I'm still testing if these can
> be made with plastic.  I think so if about 6mm thick   I'll know soon.
>  I have a test setup to check for flex in the plate.
>
> I'm working on a plan or "kit" to convert an HF mill to CNC using
> way-cheap plastic parts (< $20 material cost) and minimal machine
> work.   I'll publish the design files after it works.I've had to
> redesign/remake some parts 3 or 4 times but it comes out more simple
> each iteration

I'd like to see if I could convert this 6040 into a printer, precisely so 
I could do something along those lines but in looking around for a 
printhead, it seems the drive is much lighter so smaller motors can move 
it faster, and never the twain shall meet. Trading a 3kg 24k spindle 
motor out for a printhead the might weigh 5oz is quite a change.  I 
could buy another printer, but where I'd have to set it up has no AC. 
And good results seem to be quite temp dependent.  So I get that stuff 
from fleabay, and wait, and wait, and wait.  Thats frustrating too.

So who makes the best printer for stuff like this, at an affordable 
price?

> On Wed, May 27, 2020 at 2:06 PM Gene Heskett  
wrote:
> > On Wednesday 27 May 2020 00:51:57 Gene Heskett wrote:
> > > On Tuesday 26 May 2020 19:45:10 Chris Albertson wrote:
> > > > On Tue, May 26, 2020 at 3:01 PM Gene Heskett
> > > > 
> > >
> > > wrote:
> > > > > Those closed loop motors and controllers have arrived, and I
> > > > > puzzled by a total lack of docs other than the u-step ratios
> > > > > printed on the cover. Thats covered by dip sw1-4, but its a 6
> > > > > pos switch, and 5 & 6 are in Chinese pictograms.
> > > >
> > > > I'm following this because, as said, I plan on doing the same.
> > > > However I always read the docs BEFORE buying, no docs, I don't
> > > > buy.
> > > >
> > > > Post a photo of the Chinese characaters,  I have someone here
> > > > fluent in Chinese.  Also you can try Chinese OCR and then apply
> > > > Google Translate.
> > > > http://www.i2ocr.com/free-online-chinese-traditional-ocr
> > >
> > > I found out what they do, one is a direction reverser, the other
> > > makes it open loop.  Suits me anyway. I'll get one of those
> > > supplies and one of these on the same table and play with a
> > > function generator tomorrow, claims to be good for 200 khz steps,
> > > and has divisors out the yang, so it ought to be a dropin except
> > > for the mounts and shaft sizes so I'll need to find some timing
> > > pulleys and belts. And a nema 23 mount since that 1600 oz/in on
> > > the Z now is a nema 34 mount. An see if there is room enough
> > > behind the apron for one of them, its 124mm long in which case
> > > I'll order another for the indexer and put both of these on the
> > > Sheldon.
> >
> > Shot down there, its around 4mm too long to clear the bed.
> >
> > As it runs, the 800 or 1000 divisor seems to be the smoothest,
> > either one getting to 2500+ revs, 800 stalling, 1000 dieing because
> > of slow opto's at about 220 kilohertz. Either way plenty of turn the
> > house around torque, so I'm suitably impressed.  Now I need a 10mm
> > belt pulley with 30 teeth and a motor mount for a nema 23.  The
> > trick is finding both on this side of the pond...
> >
> > Thanks All
> >
> > > That 8 lead nema 24 on the x is slow, stalls at
> > > about 30 ipm. even when set as 4 wire parallel and all the amps a
> > > 2m542 can do. Even then it runs cooler than steppers usually do.
> > > The x belt tensioner is drilled for a 23 and then the holes were
> > > moved enough for the 24.
> > >
> > > > My guess about the cable length mismatch is that the seller you
> > > > bought this from gathers parts and packages them and this motor
> > > > was made for a use case that did not include this controller.
> > >
> > > The motor and encoder look to be an integrated unit.  So I'll have
> > > to splice it, 

Re: [Emc-users] FERROR MIN_FERROR value?

[Chris Albertson]

By total coincidence, I just made both.  I needed 30T, 40T, and 60T
pulleys.   I tried printing them and they fail after a while.  The plastic
simply will not hold the set screw then they slip on the shaft.  The big
thing is if the motor gets warm it heats the plastic.  The solution has to
print the pulley as the thin ring. My 30T puley has a 20mm hole.  Then use
the lathe to make a 20mm OD bushing with two set screws 90 degrees apart.
I make this with steel.  The pulley-ring is press fit to the steel bushing
using 5 minute epoxy.   OK, you ask "How strong can plastic teeth be?" the
answer seems to be "stronger than the rubber teeth on the belt."  The part
of the pulley that needs to be strong is the hub and that is now steel.
Making a center bored cylindrical bushing is a very easy job.   I made a
few and this method turned out the simplest and best.   Make the ring
really thin so as to make the bushing as big as you can.

I just returned from riding my bike for a few hours and notice my NEMA23
mount plate is 80% finished.   I'm still testing if these can be made with
plastic.  I think so if about 6mm thick   I'll know soon.  I have a test
setup to check for flex in the plate.

I'm working on a plan or "kit" to convert an HF mill to CNC using way-cheap
plastic parts (< $20 material cost) and minimal machine work.   I'll
publish the design files after it works.I've had to redesign/remake
some parts 3 or 4 times but it comes out more simple each iteration








On Wed, May 27, 2020 at 2:06 PM Gene Heskett  wrote:

> On Wednesday 27 May 2020 00:51:57 Gene Heskett wrote:
>
> > On Tuesday 26 May 2020 19:45:10 Chris Albertson wrote:
> > > On Tue, May 26, 2020 at 3:01 PM Gene Heskett 
> >
> > wrote:
> > > > Those closed loop motors and controllers have arrived, and I
> > > > puzzled by a total lack of docs other than the u-step ratios
> > > > printed on the cover. Thats covered by dip sw1-4, but its a 6 pos
> > > > switch, and 5 & 6 are in Chinese pictograms.
> > >
> > > I'm following this because, as said, I plan on doing the same.
> > > However I always read the docs BEFORE buying, no docs, I don't buy.
> > >
> > > Post a photo of the Chinese characaters,  I have someone here fluent
> > > in Chinese.  Also you can try Chinese OCR and then apply Google
> > > Translate. http://www.i2ocr.com/free-online-chinese-traditional-ocr
> >
> > I found out what they do, one is a direction reverser, the other makes
> > it open loop.  Suits me anyway. I'll get one of those supplies and one
> > of these on the same table and play with a function generator
> > tomorrow, claims to be good for 200 khz steps, and has divisors out
> > the yang, so it ought to be a dropin except for the mounts and shaft
> > sizes so I'll need to find some timing pulleys and belts. And a nema
> > 23 mount since that 1600 oz/in on the Z now is a nema 34 mount. An see
> > if there is room enough behind the apron for one of them, its 124mm
> > long in which case I'll order another for the indexer and put both of
> > these on the Sheldon.
> Shot down there, its around 4mm too long to clear the bed.
>
> As it runs, the 800 or 1000 divisor seems to be the smoothest, either one
> getting to 2500+ revs, 800 stalling, 1000 dieing because of slow opto's
> at about 220 kilohertz. Either way plenty of turn the house around
> torque, so I'm suitably impressed.  Now I need a 10mm belt pulley with
> 30 teeth and a motor mount for a nema 23.  The trick is finding both on
> this side of the pond...
>
> Thanks All
>
>
>
> > That 8 lead nema 24 on the x is slow, stalls at
> > about 30 ipm. even when set as 4 wire parallel and all the amps a
> > 2m542 can do. Even then it runs cooler than steppers usually do. The x
> > belt tensioner is drilled for a 23 and then the holes were moved
> > enough for the 24.
> >
> > > My guess about the cable length mismatch is that the seller you
> > > bought this from gathers parts and packages them and this motor was
> > > made for a use case that did not include this controller.
> >
> > The motor and encoder look to be an integrated unit.  So I'll have to
> > splice it, or pull the cover and see if its easily replaceable with a
> > smallish 18 or 20 gauge line cable.  Lots of layup stuffing on this
> > one to get to a matching cable jacket size, the wire gauge itself
> > isn't impressive at all. At its peak of 4 amps a coil, that cable WILL
> > heat. Not badly, but detectable.
> >
> > > When googling for the instruction, look for related controllers as
> > > I'd bet the firmware was written to run on many different sizes of
> > > controllers, not just the one you have.  Many of these are Leadshine
> > > clones so look at Leadshine web site.
> >
> > Thanks Chris, stay well.
> >
> > Cheers, Gene Heskett
>
>
> 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 

Re: [Emc-users] FERROR MIN_FERROR value?

[Gene Heskett]

On Wednesday 27 May 2020 00:51:57 Gene Heskett wrote:

> On Tuesday 26 May 2020 19:45:10 Chris Albertson wrote:
> > On Tue, May 26, 2020 at 3:01 PM Gene Heskett 
>
> wrote:
> > > Those closed loop motors and controllers have arrived, and I
> > > puzzled by a total lack of docs other than the u-step ratios
> > > printed on the cover. Thats covered by dip sw1-4, but its a 6 pos
> > > switch, and 5 & 6 are in Chinese pictograms.
> >
> > I'm following this because, as said, I plan on doing the same.
> > However I always read the docs BEFORE buying, no docs, I don't buy.
> >
> > Post a photo of the Chinese characaters,  I have someone here fluent
> > in Chinese.  Also you can try Chinese OCR and then apply Google
> > Translate. http://www.i2ocr.com/free-online-chinese-traditional-ocr
>
> I found out what they do, one is a direction reverser, the other makes
> it open loop.  Suits me anyway. I'll get one of those supplies and one
> of these on the same table and play with a function generator
> tomorrow, claims to be good for 200 khz steps, and has divisors out
> the yang, so it ought to be a dropin except for the mounts and shaft
> sizes so I'll need to find some timing pulleys and belts. And a nema
> 23 mount since that 1600 oz/in on the Z now is a nema 34 mount. An see
> if there is room enough behind the apron for one of them, its 124mm
> long in which case I'll order another for the indexer and put both of
> these on the Sheldon.
Shot down there, its around 4mm too long to clear the bed.

As it runs, the 800 or 1000 divisor seems to be the smoothest, either one 
getting to 2500+ revs, 800 stalling, 1000 dieing because of slow opto's 
at about 220 kilohertz. Either way plenty of turn the house around 
torque, so I'm suitably impressed.  Now I need a 10mm belt pulley with 
30 teeth and a motor mount for a nema 23.  The trick is finding both on 
this side of the pond...

Thanks All



> That 8 lead nema 24 on the x is slow, stalls at 
> about 30 ipm. even when set as 4 wire parallel and all the amps a
> 2m542 can do. Even then it runs cooler than steppers usually do. The x
> belt tensioner is drilled for a 23 and then the holes were moved
> enough for the 24.
>
> > My guess about the cable length mismatch is that the seller you
> > bought this from gathers parts and packages them and this motor was
> > made for a use case that did not include this controller.
>
> The motor and encoder look to be an integrated unit.  So I'll have to
> splice it, or pull the cover and see if its easily replaceable with a
> smallish 18 or 20 gauge line cable.  Lots of layup stuffing on this
> one to get to a matching cable jacket size, the wire gauge itself
> isn't impressive at all. At its peak of 4 amps a coil, that cable WILL
> heat. Not badly, but detectable.
>
> > When googling for the instruction, look for related controllers as
> > I'd bet the firmware was written to run on many different sizes of
> > controllers, not just the one you have.  Many of these are Leadshine
> > clones so look at Leadshine web site.
>
> Thanks Chris, stay well.
>
> Cheers, Gene Heskett


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] FERROR MIN_FERROR value?

[Jon Elson]

On 05/27/2020 01:52 PM, Chris Albertson wrote:



On Wed, May 27, 2020 at 11:34 AM Gene Heskett  wrote:


Have any idea how much spring there is in the iron?



I know that just leaning on the head of my Bridgeport will 
deflect the spindle .001" easily.
I often do this when using a boring bar to prevent the tip 
from scribing a line in the bore
when I retract the quill.  They are a lot springier than one 
would suspect!


Jon


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Re: [Emc-users] FERROR MIN_FERROR value?

[Chris Albertson]

Not much math.  Tie a spring scale (aka "fish scale") to an end mill placed
in the chuck and pull sideways,  Record the force on the scale and use a
dial indicator to measure the deflection of the end mill.  Plot a few
points.With no math you now know the "spring" in the system.   One
thing, be sure to measure in both X and Y directions as they are likely
different.

With only middle school algebra, you can use the plot to solve for the
spring constant (Remember Hook's Law?)  But really all you need is the plot.

That said, I doubt this matters as most people will make a final light pass
that has almost zero side force, so in the end, the "sping" does not
matter much.   I don't know the true source in in-accuracy in a typical
mill.Why are we not able to get to one micrometer?



On Wed, May 27, 2020 at 11:34 AM Gene Heskett  wrote:

> > Have any idea how much spring there is in the iron?
> >
> That will take far more math than I am capable of doing.
>
-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] FERROR MIN_FERROR value?

[Gene Heskett]

On Wednesday 27 May 2020 11:38:05 Peter C. Wallace wrote:

> On Wed, 27 May 2020, N wrote:
> > Date: Wed, 27 May 2020 17:18:16 +0200
> > From: N 
> > Reply-To: "Enhanced Machine Controller (EMC)"
> > 
> > To: "Enhanced Machine Controller (EMC)"
> >  Subject: Re: [Emc-users] FERROR
> > MIN_FERROR value?
> >
> >> On Tue, 26 May 2020 at 19:45, Gene Heskett  
wrote:
> >>> I just tried an experiment.  Since there are no pid's in that
> >>> sheldon setup, I commented out the *ERROR entries in the .ini
> >>> file. Interesting as it made zero difference in how it ran.
> >>
> >> That probably means that the default values are large.
> >>
> >> You don't need PID to measure f-error. It is the difference between
> >> motor-pos-cmd and motor-pos-fb for each axis.
> >> (Just that, and nothing more)
> >
> > But as I understand he made the test without feedback of measured
> > value ...
>
> For joints (or axis on 2.7), theres always feedback and LinuxCNC
> always checks for following errors.
>
> The following error settings make no difference in motion except that
> you will get a fault and motion will be stopped if they are exceeded.
>
> If you dont set the following error or minimum following error they
> default to 1.0 so are effectively disabled.
>
Which is why one should make a sub2 and scope the output while abusing 
the machine. 

I've not done that, as other more pressing issues with lack of doctors 
and prescriptions are makeing me go buy a smart fone, then learn how to 
use it so we can do teleconferencing with the doc that will renew the 
prescriptions.  So I've bought a Galaxy A10e and its charging now. Wish 
me luck if you've any to spare.

Thanks Peter.


> Peter Wallace
> Mesa Electronics
>
>
>
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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)
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] FERROR MIN_FERROR value?

[Gene Heskett]

On Wednesday 27 May 2020 11:20:46 N wrote:

> > On Tuesday 26 May 2020 16:29:17 Chris Albertson wrote:
> > > Gene,
> > >
> > > I'm also looking at using a closed-loop stepper for a z-axis
> > > drive. On my system the z-motor's torque holds the full weight of
> > > the head. With a standard open loop motor full current is used and
> > > the motor gets hot because there is more current than needed.  The
> > > closed loop system puts only as much current into the motor as is
> > > required to hold position.
> > >
> > > My calculation says that the force of gravity pulling the head
> > > down will generate roughly just under 1.2 Nm of static torque on
> > > the ball screw. That is the price one pays for using ball screws
> > > vs acme lead screws.  The ball screw is back drivable with very
> > > little friction. But it has zero measurable backlash.  (The cheap
> > > $50 Chinees screw is perfect as far as my dial indicator can
> > > tell.)
> >
> > If its loaded by head weight, and the gibs are well adjusted and
> > wet, the weight preload cancels the backlash. Too much there will
> > make sloppy rigid threads.
> >
> > > The build-in z-motor encoder has 1000 lines per revolution, so I
> > > assume if I use 1/4 micro-steps that the motor will always have at
> > > most 1/1000 of a revolution position error.   The z-axis lead
> > > screw is 5mm pitch so hopefully, I get 0.005 mm resolution (Yes,
> > > this is better than needed)
> >
> > Absolutely, theres more spring in the frame iron than that.
>
> Have any idea how much spring there is in the iron?
>
That will take far more math than I am capable of doing.

>
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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)
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Re: [Emc-users] FERROR MIN_FERROR value?

[Gene Heskett]

On Wednesday 27 May 2020 11:18:16 N wrote:

> > On Tue, 26 May 2020 at 19:45, Gene Heskett  
wrote:
> > > I just tried an experiment.  Since there are no pid's in that
> > > sheldon setup, I commented out the *ERROR entries in the .ini
> > > file. Interesting as it made zero difference in how it ran.
> >
> > That probably means that the default values are large.
> >
> > You don't need PID to measure f-error. It is the difference between
> > motor-pos-cmd and motor-pos-fb for each axis.
> > (Just that, and nothing more)
>
> But as I understand he made the test without feedback of measured
> value ...
pos.fb was/is connected. Both axises.
Thanks.

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
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Re: [Emc-users] FERROR MIN_FERROR value?

[Peter C. Wallace]

On Wed, 27 May 2020, N wrote:


Date: Wed, 27 May 2020 17:18:16 +0200
From: N 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] FERROR MIN_FERROR value?


On Tue, 26 May 2020 at 19:45, Gene Heskett  wrote:


I just tried an experiment.  Since there are no pid's in that sheldon
setup, I commented out the *ERROR entries in the .ini file. Interesting
as it made zero difference in how it ran.


That probably means that the default values are large.

You don't need PID to measure f-error. It is the difference between
motor-pos-cmd and motor-pos-fb for each axis.
(Just that, and nothing more)


But as I understand he made the test without feedback of measured value ...




For joints (or axis on 2.7), theres always feedback and LinuxCNC always checks 
for following errors.


The following error settings make no difference in motion except that you will 
get a fault and motion will be stopped if they are exceeded.


If you dont set the following error or minimum following error they default to 
1.0 so are effectively disabled.



Peter Wallace
Mesa Electronics



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Re: [Emc-users] FERROR MIN_FERROR value?

[N]

> On Tuesday 26 May 2020 16:29:17 Chris Albertson wrote:
> 
> > Gene,
> >
> > I'm also looking at using a closed-loop stepper for a z-axis drive.   
> > On my system the z-motor's torque holds the full weight of the head. 
> > With a standard open loop motor full current is used and the motor
> > gets hot because there is more current than needed.  The closed loop
> > system puts only as much current into the motor as is required to hold
> > position.
> >
> > My calculation says that the force of gravity pulling the head down
> > will generate roughly just under 1.2 Nm of static torque on the ball
> > screw. That is the price one pays for using ball screws vs acme lead
> > screws.  The ball screw is back drivable with very little friction.  
> > But it has zero measurable backlash.  (The cheap $50 Chinees screw is
> > perfect as far as my dial indicator can tell.)
> >
> If its loaded by head weight, and the gibs are well adjusted and wet, the 
> weight preload cancels the backlash. Too much there will make sloppy 
> rigid threads.
> 
> > The build-in z-motor encoder has 1000 lines per revolution, so I
> > assume if I use 1/4 micro-steps that the motor will always have at
> > most 1/1000 of a revolution position error.   The z-axis lead screw is
> > 5mm pitch so hopefully, I get 0.005 mm resolution (Yes, this is better
> > than needed)
> 
> Absolutely, theres more spring in the frame iron than that.

Have any idea how much spring there is in the iron?


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Re: [Emc-users] FERROR MIN_FERROR value?

[N]

> On Tue, 26 May 2020 at 19:45, Gene Heskett  wrote:
> 
> > I just tried an experiment.  Since there are no pid's in that sheldon
> > setup, I commented out the *ERROR entries in the .ini file. Interesting
> > as it made zero difference in how it ran.
> 
> That probably means that the default values are large.
> 
> You don't need PID to measure f-error. It is the difference between
> motor-pos-cmd and motor-pos-fb for each axis.
> (Just that, and nothing more)

But as I understand he made the test without feedback of measured value ...


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Re: [Emc-users] FERROR MIN_FERROR value?

[Gene Heskett]

On Tuesday 26 May 2020 19:45:10 Chris Albertson wrote:

> On Tue, May 26, 2020 at 3:01 PM Gene Heskett  
wrote:
> > Those closed loop motors and controllers have arrived, and I puzzled
> > by a total lack of docs other than the u-step ratios printed on the
> > cover. Thats covered by dip sw1-4, but its a 6 pos switch, and 5 & 6
> > are in Chinese pictograms.
>
> I'm following this because, as said, I plan on doing the same. 
> However I always read the docs BEFORE buying, no docs, I don't buy.
>
> Post a photo of the Chinese characaters,  I have someone here fluent
> in Chinese.  Also you can try Chinese OCR and then apply Google
> Translate. http://www.i2ocr.com/free-online-chinese-traditional-ocr

I found out what they do, one is a direction reverser, the other makes it 
open loop.  Suits me anyway. I'll get one of those supplies and one of 
these on the same table and play with a function generator tomorrow, 
claims to be good for 200 khz steps, and has divisors out the yang, so 
it ought to be a dropin except for the mounts and shaft sizes so I'll 
need to find some timing pulleys and belts. And a nema 23 mount since 
that 1600 oz/in on the Z now is a nema 34 mount. An see if there is room 
enough behind the apron for one of them, its 124mm long in which case 
I'll order another for the indexer and put both of these on the Sheldon. 
That 8 lead nema 24 on the x is slow, stalls at about 30 ipm. even when 
set as 4 wire parallel and all the amps a 2m542 can do. Even then it 
runs cooler than steppers usually do. The x belt tensioner is drilled 
for a 23 and then the holes were moved enough for the 24.

> My guess about the cable length mismatch is that the seller you bought
> this from gathers parts and packages them and this motor was made for
> a use case that did not include this controller.

The motor and encoder look to be an integrated unit.  So I'll have to 
splice it, or pull the cover and see if its easily replaceable with a 
smallish 18 or 20 gauge line cable.  Lots of layup stuffing on this one 
to get to a matching cable jacket size, the wire gauge itself isn't 
impressive at all. At its peak of 4 amps a coil, that cable WILL heat.  
Not badly, but detectable.
>
> When googling for the instruction, look for related controllers as I'd
> bet the firmware was written to run on many different sizes of
> controllers, not just the one you have.  Many of these are Leadshine
> clones so look at Leadshine web site.

Thanks Chris, stay well.

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] FERROR MIN_FERROR value?

[Chris Albertson]

On Tue, May 26, 2020 at 3:01 PM Gene Heskett  wrote:

>
> Those closed loop motors and controllers have arrived, and I puzzled by a
> total lack of docs other than the u-step ratios printed on the cover.
> Thats covered by dip sw1-4, but its a 6 pos switch, and 5 & 6 are in
> Chinese pictograms.


I'm following this because, as said, I plan on doing the same.  However I
always read the docs BEFORE buying, no docs, I don't buy.

Post a photo of the Chinese characaters,  I have someone here fluent in
Chinese.  Also you can try Chinese OCR and then apply Google Translate.
http://www.i2ocr.com/free-online-chinese-traditional-ocr

My guess about the cable length mismatch is that the seller you bought this
from gathers parts and packages them and this motor was made for a use case
that did not include this controller.

When googling for the instruction, look for related controllers as I'd bet
the firmware was written to run on many different sizes of controllers, not
just the one you have.  Many of these are Leadshine clones so look at
Leadshine web site.

-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] FERROR MIN_FERROR value?

[andy pugh]

On Tue, 26 May 2020 at 19:45, Gene Heskett  wrote:

> I just tried an experiment.  Since there are no pid's in that sheldon
> setup, I commented out the *ERROR entries in the .ini file. Interesting
> as it made zero difference in how it ran.

That probably means that the default values are large.

You don't need PID to measure f-error. It is the difference between
motor-pos-cmd and motor-pos-fb for each axis.
(Just that, and nothing more)

-- 
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] FERROR MIN_FERROR value?

[Gene Heskett]

On Tuesday 26 May 2020 16:29:17 Chris Albertson wrote:

> Gene,
>
> I'm also looking at using a closed-loop stepper for a z-axis drive.   
> On my system the z-motor's torque holds the full weight of the head. 
> With a standard open loop motor full current is used and the motor
> gets hot because there is more current than needed.  The closed loop
> system puts only as much current into the motor as is required to hold
> position.
>
> My calculation says that the force of gravity pulling the head down
> will generate roughly just under 1.2 Nm of static torque on the ball
> screw. That is the price one pays for using ball screws vs acme lead
> screws.  The ball screw is back drivable with very little friction.  
> But it has zero measurable backlash.  (The cheap $50 Chinees screw is
> perfect as far as my dial indicator can tell.)
>
If its loaded by head weight, and the gibs are well adjusted and wet, the 
weight preload cancels the backlash. Too much there will make sloppy 
rigid threads.

> The build-in z-motor encoder has 1000 lines per revolution, so I
> assume if I use 1/4 micro-steps that the motor will always have at
> most 1/1000 of a revolution position error.   The z-axis lead screw is
> 5mm pitch so hopefully, I get 0.005 mm resolution (Yes, this is better
> than needed)

Absolutely, theres more spring in the frame iron than that.
>
> Using a closed-loop motor should make a big improvement.   Stepper
> online has a 12Nm NEMA 34 close-loop 1000 line per rev kit with motor,
> controller and cables for $120.
>
> *Back on-topic.*   With the price of glass scales having dropped to
> way-cheap.  Is there any reason NOT to place a closed-loop control
> around even open-loop steppers?   Look at this:
> amazon.com/TOAUTO-Digital-Readout-Milling-Machine...
> X9171J/ref=sr_1_9?dchild=1=glass%2Bdro%2Bscale=1590523919&
>sr=8-9=1>
>
> This is a serious question.  I wonder if doing so would remove the
> problem of backlash and flex?  These are 5 uM scales for $65  Even if
> they are 4X worse than spec'd they would offer a big improvement.
>
I'd say, but how to install them so they are protected, the 64 million 
sheckel question indeed.
> On Tue, May 26, 2020 at 11:45 AM Gene Heskett  
wrote:
> > On Monday 25 May 2020 20:43:45 Gene Heskett wrote:
> > > On Monday 25 May 2020 18:33:29 Jon Elson wrote:
> > > > On 05/25/2020 02:50 PM, N wrote:
> > > > > Do anyone here have any suggestion for FERROR and MIN_FERROR
> > > > > values?
> > > >
> > > > It depends on your "user units", as well as the general
> > > > accuracy and speed of the machine.
> > > > FERROR is a multiplier to velocity in user units/second that
> > > > is added to MIN_FERROR.
> > > > MIN_FERROR is the allowable following error with the machine
> > > > not moving.
> > > >
> > > > On a servo system, you should have Halscope graph the
> > > > following error and find out what
> > > > your actual errors are, and then set MIN_FERROR
> > > > accordingly.  Then, set FERROR to
> > > > accommodate larger error at rapid traverse speed.
> > > >
> > > > There's no one good value for everybody.
> > > >
> > > > Jon
> > >
> > > Perhaps this might be a good time to discuss/develop a recommended
> > > good practice procedure to be applied to a machine w/o PID's as
> > > there's none in the pi running the sheldon, and none in the
> > > D5215MW running the 6040.
> > >
> > > Can you recommend a procedure that Just Works, where the machine
> > > is expected to follow what the TP actually outputs, with a
> > > tolerance setting profile that its capable of staying inside of?
> > >
> > > Without PID's, where do we get a following error that we can see
> > > on the halscope?  Or do I need to put PID's in before this makes
> > > sense? Or do I make a sub2 out of a sum2 just to develop the error
> > > signal? Eventually that would use up the cpu cycles saved by not
> > > using the PID's.  And it all, to me, adds up to more give between
> > > the TP and what the machine does, allowing more error than w/o the
> > > PID.
> > >
> > > Seems to me there should be some "rules of thumb" to apply here.
> >
> > I just tried an experiment.  Since there are no pid's in that
> > sheldon setup, I commented out the *ERROR entries in the .ini file.
> > Interesting as it made zero difference in how it ran. So, it appears
> > that I'll need to synth an error signal, and the best way I can
> > think of it to subtract the command to a stepgen from the feedback,
> > or vice-versa, but w/o an encoder actually measuring that axis, its
> > not going to tell me anything but the time lags caused by the addf
> > order.  Food to feed a "what if" at some point...  Perhaps if I cab
> > break into the encoder?
> >
> > Acc to fedex I should get those 3 phase closed loop motors late
> > today. AIUI, they do have an error output, but its yay or nay I
> > think, but the 3NM is way too long to fit behind the apron and drive
> > the X. I 

Re: [Emc-users] FERROR MIN_FERROR value?

[Gene Heskett]

On Tuesday 26 May 2020 15:55:36 N wrote:

> > ...
> > I just tried an experiment.  Since there are no pid's in that
> > sheldon setup, I commented out the *ERROR entries in the .ini file.
> > Interesting as it made zero difference in how it ran. So, it appears
> > that I'll need to synth an error signal, and the best way I can
> > think of it to subtract the command to a stepgen from the feedback,
> > or vice-versa, but w/o an encoder actually measuring that axis, its
> > not going to tell me anything but the time lags caused by the addf
> > order.  ...
>
> It come as a suprise it tell anything but the time lag?
>
> I already discovered time lag add quite much error but it could be
> compensanted.
>
Not compensated for, but re-arrange the addf order until any one signal 
falls thru its whole processing chain in one thread invocation.  So 
follow a signal from origin to output, and use that as your addf order 
top to bottom. Timing problems dissappear as if by magic. 
>
> Nicklas Karlsson
>
>
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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)
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] FERROR MIN_FERROR value?

[Gene Heskett]

On Tuesday 26 May 2020 11:55:05 Jon Elson wrote:

> On 05/25/2020 07:43 PM, Gene Heskett wrote:
> > Without PID's, where do we get a following error that we
> > can see on the halscope?
>
> OK, WITHOUT a PID, then the step generators have a maximum
> speed, set by (possibly)
> BASE_PERIOD, step_width and step_space.
No BASE_PERIOD, servo thread only

STEPLEN & STEP_SPACE vary acc the driver but would be 3250 x 2 for the 
slowest. 6500 ns but longer at direction changes. Thats nominally 155 
kilohertz for a max step rate, so in reality, motor inductance causeing 
a loss of torque and a stall will be the first effect actually seen.  
Somewhat mitigated by raising the applied voltage, within the limits 
imposed by the drivers power stage.  Thats a per second value.  But lets 
be safe and assume 100 kilohertz. plug in the microstep setting of the 
driver and get an inches per second if you punched all the right 
buttons.  Thats a huge IF. 
 
> If you set maximum 
> velocity in the ini file
> above that limit, you will get following errors.  So, you
> have to know from the setup
> of the step generators what the max speed is, and then be
> sure to not set max velocity above
> that.  You should have no need to scope it, but you could
> probably get this on most systems
> by looking at the commanded position and the actual
> position, if the step generator provides
> this.
>
The mesa cards provides a .pos-fb data line that I assume is how many 
steps, and should match the .pos-cmd value from the TP? That hookup is 
present in the .hal file. The MAX_VEL's are set at 50 to 75% of the 
stall speeds.

Subject change:

Those closed loop motors and controllers have arrived, and I puzzled by a 
total lack of docs other than the u-step ratios printed on the cover.  
Thats covered by dip sw1-4, but its a 6 pos switch, and 5 & 6 are in 
Chinese pictograms. It also has a 6 wire rj jack like a phone handset 
labeled rs232.  The motor has about an 18" power cord, but the encoder 
is at least 2 meters.  Obviously I'll have to extend the motor cable.  
And the motors are shorter than I assumed from the pix as I was 
comparing the driver to a 2m542, and its at least 25% smaller than a 
2m542. It may even fit the X on the sheldon, maybe... thats a nema-24 
motor in there now. Dual shaft, back shaft clears the bed about 1/4" 
now.

Now to see if my google-foo can find me some docs on the care and feeding 
of a "LCDA367H" driver.  There are also a pair of 220 ohm 1/8 watt R's 
in each box???

Manual was easy, but rs232 for tuning is not documented, claims it 
automatic.  We'll see. I bought some 48 volt, 7.5 amp rated supplies 
I'll turn down to 42 volts as the driver is rated for 20-50. Ack the 
manpages, the resistors are for 24 volt step/dir sigs.

Guinea Pig at work IOW. But I still don't grok why the encoder cable is 2 
meters long, but the motors cable is half a meter, when the two plugs 
are cheek to jowl adjacent on the controller.

Haven't had net or phone most of the day. I get em both from the local 
cable, shentel.  But no cable tv.

Stay well Jon.

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] FERROR MIN_FERROR value?

[Chris Albertson]

Gene,

I'm also looking at using a closed-loop stepper for a z-axis drive.On
my system the z-motor's torque holds the full weight of the head.  With a
standard open loop motor full current is used and the motor gets hot
because there is more current than needed.  The closed loop system puts
only as much current into the motor as is required to hold position.

My calculation says that the force of gravity pulling the head down will
generate roughly just under 1.2 Nm of static torque on the ball screw.
That is the price one pays for using ball screws vs acme lead screws.  The
ball screw is back drivable with very little friction.   But it has zero
measurable backlash.  (The cheap $50 Chinees screw is perfect as far as my
dial indicator can tell.)

The build-in z-motor encoder has 1000 lines per revolution, so I assume if
I use 1/4 micro-steps that the motor will always have at most 1/1000 of a
revolution position error.   The z-axis lead screw is 5mm pitch so
hopefully, I get 0.005 mm resolution (Yes, this is better than needed)

Using a closed-loop motor should make a big improvement.   Stepper online
has a 12Nm NEMA 34 close-loop 1000 line per rev kit with motor, controller
and cables for $120.

*Back on-topic.*   With the price of glass scales having dropped to
way-cheap.  Is there any reason NOT to place a closed-loop control around
even open-loop steppers?   Look at this:
amazon.com/TOAUTO-Digital-Readout-Milling-Machine...


This is a serious question.  I wonder if doing so would remove the problem
of backlash and flex?  These are 5 uM scales for $65  Even if they are 4X
worse than spec'd they would offer a big improvement.








On Tue, May 26, 2020 at 11:45 AM Gene Heskett  wrote:

> On Monday 25 May 2020 20:43:45 Gene Heskett wrote:
>
> > On Monday 25 May 2020 18:33:29 Jon Elson wrote:
> > > On 05/25/2020 02:50 PM, N wrote:
> > > > Do anyone here have any suggestion for FERROR and MIN_FERROR
> > > > values?
> > >
> > > It depends on your "user units", as well as the general
> > > accuracy and speed of the machine.
> > > FERROR is a multiplier to velocity in user units/second that
> > > is added to MIN_FERROR.
> > > MIN_FERROR is the allowable following error with the machine
> > > not moving.
> > >
> > > On a servo system, you should have Halscope graph the
> > > following error and find out what
> > > your actual errors are, and then set MIN_FERROR
> > > accordingly.  Then, set FERROR to
> > > accommodate larger error at rapid traverse speed.
> > >
> > > There's no one good value for everybody.
> > >
> > > Jon
> >
> > Perhaps this might be a good time to discuss/develop a recommended
> > good practice procedure to be applied to a machine w/o PID's as
> > there's none in the pi running the sheldon, and none in the D5215MW
> > running the 6040.
> >
> > Can you recommend a procedure that Just Works, where the machine is
> > expected to follow what the TP actually outputs, with a tolerance
> > setting profile that its capable of staying inside of?
> >
> > Without PID's, where do we get a following error that we can see on
> > the halscope?  Or do I need to put PID's in before this makes sense?
> > Or do I make a sub2 out of a sum2 just to develop the error signal?
> > Eventually that would use up the cpu cycles saved by not using the
> > PID's.  And it all, to me, adds up to more give between the TP and
> > what the machine does, allowing more error than w/o the PID.
> >
> > Seems to me there should be some "rules of thumb" to apply here.
>
> I just tried an experiment.  Since there are no pid's in that sheldon
> setup, I commented out the *ERROR entries in the .ini file. Interesting
> as it made zero difference in how it ran. So, it appears that I'll need
> to synth an error signal, and the best way I can think of it to subtract
> the command to a stepgen from the feedback, or vice-versa, but w/o an
> encoder actually measuring that axis, its not going to tell me anything
> but the time lags caused by the addf order.  Food to feed a "what if" at
> some point...  Perhaps if I cab break into the encoder?
>
> Acc to fedex I should get those 3 phase closed loop motors late today.
> AIUI, they do have an error output, but its yay or nay I think, but the
> 3NM is way too long to fit behind the apron and drive the X. I do intend
> to put one of the 3NM's on the Z. Lots of room there. That 1600 oz/in
> there now is so much overkill its not even funny. It rattles the whole
> machine when it moves. That should at least give me an error stop if the
> motor doesn't follow orders.
>
> Stay well everybody.
>
> 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
> 

Re: [Emc-users] FERROR MIN_FERROR value?

[N]

> ...
> I just tried an experiment.  Since there are no pid's in that sheldon 
> setup, I commented out the *ERROR entries in the .ini file. Interesting 
> as it made zero difference in how it ran. So, it appears that I'll need 
> to synth an error signal, and the best way I can think of it to subtract 
> the command to a stepgen from the feedback, or vice-versa, but w/o an 
> encoder actually measuring that axis, its not going to tell me anything 
> but the time lags caused by the addf order.  ...

It come as a suprise it tell anything but the time lag?

I already discovered time lag add quite much error but it could be compensanted.


Nicklas Karlsson


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Re: [Emc-users] FERROR MIN_FERROR value?

[Gene Heskett]

On Monday 25 May 2020 20:43:45 Gene Heskett wrote:

> On Monday 25 May 2020 18:33:29 Jon Elson wrote:
> > On 05/25/2020 02:50 PM, N wrote:
> > > Do anyone here have any suggestion for FERROR and MIN_FERROR
> > > values?
> >
> > It depends on your "user units", as well as the general
> > accuracy and speed of the machine.
> > FERROR is a multiplier to velocity in user units/second that
> > is added to MIN_FERROR.
> > MIN_FERROR is the allowable following error with the machine
> > not moving.
> >
> > On a servo system, you should have Halscope graph the
> > following error and find out what
> > your actual errors are, and then set MIN_FERROR
> > accordingly.  Then, set FERROR to
> > accommodate larger error at rapid traverse speed.
> >
> > There's no one good value for everybody.
> >
> > Jon
>
> Perhaps this might be a good time to discuss/develop a recommended
> good practice procedure to be applied to a machine w/o PID's as
> there's none in the pi running the sheldon, and none in the D5215MW
> running the 6040.
>
> Can you recommend a procedure that Just Works, where the machine is
> expected to follow what the TP actually outputs, with a tolerance
> setting profile that its capable of staying inside of?
>
> Without PID's, where do we get a following error that we can see on
> the halscope?  Or do I need to put PID's in before this makes sense? 
> Or do I make a sub2 out of a sum2 just to develop the error signal?
> Eventually that would use up the cpu cycles saved by not using the
> PID's.  And it all, to me, adds up to more give between the TP and
> what the machine does, allowing more error than w/o the PID.
>
> Seems to me there should be some "rules of thumb" to apply here.

I just tried an experiment.  Since there are no pid's in that sheldon 
setup, I commented out the *ERROR entries in the .ini file. Interesting 
as it made zero difference in how it ran. So, it appears that I'll need 
to synth an error signal, and the best way I can think of it to subtract 
the command to a stepgen from the feedback, or vice-versa, but w/o an 
encoder actually measuring that axis, its not going to tell me anything 
but the time lags caused by the addf order.  Food to feed a "what if" at 
some point...  Perhaps if I cab break into the encoder?

Acc to fedex I should get those 3 phase closed loop motors late today.
AIUI, they do have an error output, but its yay or nay I think, but the 
3NM is way too long to fit behind the apron and drive the X. I do intend 
to put one of the 3NM's on the Z. Lots of room there. That 1600 oz/in 
there now is so much overkill its not even funny. It rattles the whole 
machine when it moves. That should at least give me an error stop if the 
motor doesn't follow orders.

Stay well everybody.

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] FERROR MIN_FERROR value?

[Jon Elson]

On 05/25/2020 07:43 PM, Gene Heskett wrote:
Without PID's, where do we get a following error that we 
can see on the halscope?
OK, WITHOUT a PID, then the step generators have a maximum 
speed, set by (possibly)
BASE_PERIOD, step_width and step_space.  If you set maximum 
velocity in the ini file
above that limit, you will get following errors.  So, you 
have to know from the setup
of the step generators what the max speed is, and then be 
sure to not set max velocity above
that.  You should have no need to scope it, but you could 
probably get this on most systems
by looking at the commanded position and the actual 
position, if the step generator provides

this.

Jon


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Re: [Emc-users] FERROR MIN_FERROR value?

[N]

> > Do anyone here have any suggestion for FERROR and MIN_FERROR values?
> >
> It depends on your "user units", as well as the general 
> accuracy and speed of the machine.

Unit is not important just have know which is used and do conversion from inch 
to mm if necessary. Try to figure out what is considered good accuracy? Or what 
accuracy is common to achieve?

Including only control accuracy. Stop stationary within less 10µm is possible 
but it take some time to reach stationary point. Then at move accuracy will be 
less, would guess maybe reliable within 0.1mm=100µm is possible, this is a 
factor ten more.

> FERROR is a multiplier to velocity in user units/second that 
> is added to MIN_FERROR.
> MIN_FERROR is the allowable following error with the machine 
> not moving.
> 
> On a servo system, you should have Halscope graph the 
> following error and find out what
> your actual errors are, and then set MIN_FERROR 
> accordingly.  Then, set FERROR to
> accommodate larger error at rapid traverse speed.

Plotting is no problem, already do that. There is a spike inaccuracy then 
changing direction and feed using linear move. I can most probably reduce 
following error by spending more time so it is at least partly a question about 
then it should be considered good enough.

I found there are some more 
https://www.engineersedge.com/mechanical,045tolerances/general_iso_tolerance_.htm
 and less 
https://www.engineersedge.com/mechanical,045tolerances/general_iso_tolerance_.htm
 standard tolerances but expect machining method, in this case a CNC machine 
have some accuracy limitations due to machine and tool elasticity.


Regards Nicklas Karlsson


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Re: [Emc-users] FERROR MIN_FERROR value?

[Gene Heskett]

On Monday 25 May 2020 18:33:29 Jon Elson wrote:

> On 05/25/2020 02:50 PM, N wrote:
> > Do anyone here have any suggestion for FERROR and MIN_FERROR values?
>
> It depends on your "user units", as well as the general
> accuracy and speed of the machine.
> FERROR is a multiplier to velocity in user units/second that
> is added to MIN_FERROR.
> MIN_FERROR is the allowable following error with the machine
> not moving.
>
> On a servo system, you should have Halscope graph the
> following error and find out what
> your actual errors are, and then set MIN_FERROR
> accordingly.  Then, set FERROR to
> accommodate larger error at rapid traverse speed.
>
> There's no one good value for everybody.
>
> Jon

Perhaps this might be a good time to discuss/develop a recommended good 
practice procedure to be applied to a machine w/o PID's as there's none 
in the pi running the sheldon, and none in the D5215MW running the 6040.  

Can you recommend a procedure that Just Works, where the machine is 
expected to follow what the TP actually outputs, with a tolerance 
setting profile that its capable of staying inside of?

Without PID's, where do we get a following error that we can see on the 
halscope?  Or do I need to put PID's in before this makes sense?  Or do 
I make a sub2 out of a sum2 just to develop the error signal?  
Eventually that would use up the cpu cycles saved by not using the 
PID's.  And it all, to me, adds up to more give between the TP and what 
the machine does, allowing more error than w/o the PID.

Seems to me there should be some "rules of thumb" to apply here.


>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
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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)
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] FERROR MIN_FERROR value?

[Jon Elson]

On 05/25/2020 02:50 PM, N wrote:

Do anyone here have any suggestion for FERROR and MIN_FERROR values?



It depends on your "user units", as well as the general 
accuracy and speed of the machine.
FERROR is a multiplier to velocity in user units/second that 
is added to MIN_FERROR.
MIN_FERROR is the allowable following error with the machine 
not moving.


On a servo system, you should have Halscope graph the 
following error and find out what
your actual errors are, and then set MIN_FERROR 
accordingly.  Then, set FERROR to

accommodate larger error at rapid traverse speed.

There's no one good value for everybody.

Jon


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