On Saturday 16 May 2020 16:01:08 Ken Strauss wrote:
> 3 Nm is about 2.21 ft-lb so at 12:1 reduction I think it would provide
> about 26.5 ft-lb. For comparison, the Tormach microArc4 (harmonic
> drive with NEMA 34 stepper) claims to provide a maximum holding torque
> of 28 ft-lbs but they suggest
I got time to get back to my machine and indeed it seems to be working much
better now.
I tried
current-maxlim = 100
current-minlim = -100
current-scalemax = 100
and things are much snappier.
On Sat, May 16, 2020 at 4:47 PM Curtis Dutton wrote:
> Yes the current is set to 1 or -1 while this
I had never found an analysis of repeatability or transmission accuracy in the
advertising or Wikipedia for Cycloidal gear boxes.
Given the non engineering drawings at https://www.darali.com/page17.html, I was
thinking they would allow greater holding power on a stepper motor in a fourth
or
On Sat, 16 May 2020, Curtis Dutton wrote:
Date: Sat, 16 May 2020 12:53:29 -0400
From: Curtis Dutton
Reply-To: "Enhanced Machine Controller (EMC)"
To: "Enhanced Machine Controller (EMC)"
Subject: [Emc-users] Trouble with 8i20 settings.
I believe that I'm having trouble understanding how
Yes the current is set to 1 or -1 while this is occurring.
I'm willing to say that it may just be as fast as it will go. Which will be
fine for my application. I just wasn't sure.
But just so I understand. If I wanted my output range to be 100 to -100
I would set NVMAXCURRENT 3000 (30 AMPS)
On Saturday 16 May 2020 12:48:22 Chris Albertson wrote:
> Some types of motor drives don't have backlash. Timing belts,
> cycloidal, and harmonic drives don't have enough backlash to worry
> about. The linked harmonic drive is as good as the leadscrew on the
> other axis.
>
But slack, any, in a
The concern I have is that the cycloidal lobes will be unHardened and will
wear out faster.
They really need to be Hardened.
And If I made one it would have a decent size air or hydraulic clamp to
hold everything rigid for 4th axis positional work.
On Sun, May 17, 2020, 10:23 AM Chris Albertson
One interesting and fun option is to make your own cycloidical reduction.
These are completely buildable on a CNC mill that can do 2 1/2 D machining
on mild steel. Unlike most other gears, these can be cut from plate stock
with just an end mill. THey can be 3D printed too.
See the wiki link
On Sat, May 16, 2020 at 12:24 PM Gene Heskett wrote:
>
> Which then brings up the need for some math. So how would one go about
> getting from a 3 phase stepper motors holding power, say 3 NM to lbs/ft
> at the output of a 12/1 cycloidal gear?
>
> Assuming zero losses in the bearings, which I'd
On Sat, 16 May 2020 at 17:56, Curtis Dutton wrote:
> I've tried to look for some documentation explaining exactly how those
> values work, but I can't seem to find it.
It might not be in the most obvious place.
http://linuxcnc.org/docs/2.7/html/man/man9/sserial.9.html#8i20
But that comes
Some types of motor drives don't have backlash. Timing belts,
cycloidal, and harmonic drives don't have enough backlash to worry
about. The linked harmonic drive is as good as the leadscrew on the
other axis.
On Fri, May 15, 2020 at 10:53 PM Roland Jollivet
wrote:
>
> I've been thinking about
I agree with Lester. Searching for that description on the www.ebay.ca
eventually does bring up that particular supplier along with about 10 others.
All located in either China or Korea. Most of the motors are more in the $800
range. It almost looks like various companies are all sourcing
3 Nm is about 2.21 ft-lb so at 12:1 reduction I think it would provide about
26.5 ft-lb. For comparison, the Tormach microArc4 (harmonic drive with NEMA
34 stepper) claims to provide a maximum holding torque of 28 ft-lbs but they
suggest using only half of that to avoid excessive wear. I don't
> -Original Message-
> From: Gene Heskett [mailto:ghesk...@shentel.net]
> Sent: Saturday, May 16, 2020 4:32 PM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Cheaper than normal FHA-25B
>
> On Saturday 16 May 2020 16:01:08 Ken Strauss wrote:
>
> > 3 Nm is about 2.21 ft-lb
THere are two different kinds of drives. The "harmonic" and
"cycloidal". THey both use an eccentric center gear but the teeth
have different shape. The cyclodal type use arcs and have fewer
teeth. This is why I said they could be made using average equipment
-- just an end-mill.
You can get
I believe that I'm having trouble understanding how to set an 8i20 up
properly.
It is connected to a 2.5KW 200V AC servo which can take a maximum current
of 44.5 amps. Maximum speed of 5000RPM.
It is running a lathe spindle. I am able to get it to spin up but it seems
a bit sluggish. I also
On Saturday 16 May 2020 12:53:29 Curtis Dutton wrote:
> I believe that I'm having trouble understanding how to set an 8i20 up
> properly.
>
> It is connected to a 2.5KW 200V AC servo which can take a maximum
> current of 44.5 amps. Maximum speed of 5000RPM.
>
> It is running a lathe spindle. I am
On Saturday 16 May 2020 17:13:23 Chris Albertson wrote:
> On Sat, May 16, 2020 at 12:24 PM Gene Heskett
wrote:
> > Which then brings up the need for some math. So how would one go
> > about getting from a 3 phase stepper motors holding power, say 3 NM
> > to lbs/ft at the output of a 12/1
On Saturday 16 May 2020 15:09:08 Chris Albertson wrote:
> One interesting and fun option is to make your own cycloidical
> reduction. These are completely buildable on a CNC mill that can do 2
> 1/2 D machining on mild steel. Unlike most other gears, these can be
> cut from plate stock with just
Hey Chris.
That's awesome. I was just looking at that video lol.
Do you know how he is designing these. I know that the lobes are
calculated by a equation.
It would be good to see the equations that go into this and any plug-ins he
uses etc.
I'm quite keen to build one of these. Like you
Chris
So do they use some needle roller bearings that run on the lobes or
something?
I could make that work I reckon. I already have the massive big angular
contact bearings and if I can make the lobe part OK then I'm away.
Add a big clamp to hold everything rigid and tight for milling and I
Paul Gould is doing good work with these reduction drives. This video
shows how a triple reduction system works and just how simple it is.
Note that all the points of contact with the plastic lobes are ball bearing
units.This unit is about as complex as they get and it is still easy to
see
Actually the 3D printed plastic cycloidal lobes are lasting quite a
while. The reason it can work is that rather then the round pins
shown on the demo video, real systems use tiny sealed ball bearing
units. So there is no sliding contact on the lobes.
On Sat, May 16, 2020 at 4:40 PM andrew beck
I assume that you are thinking of
https://hackaday.io/project/19405-strain-wave-gear-with-timing-belts Thanks
for the interesting idea!
> -Original Message-
> From: Chris Albertson [mailto:albertson.ch...@gmail.com]
> Sent: Saturday, May 16, 2020 6:21 PM
> To: Enhanced Machine Controller
Hi Dave,
I think the question being raised is whether it's possible to create a zero
backlash 4th or 5th axis with COTS hardware for less money than a harmonic
drive or the cycloidal gearboxes.
John
> -Original Message-
> From: David Berndt [mailto:ber...@uberwin.com]
> Sent:
When reasonably sized harmonic drives with servo motors inbuilt are 250$
on ebay, they are COTS. So the answer is yes. Just buy one of those and
move on to solving a more interesting problem or making whatever the
machine is supposed to make.
-Dave
On Sat, 16 May 2020 02:49:55 -0400,
On 15/05/2020 13:08, andy pugh wrote:
I have no connection with the vendor, if you order one and receive
dolls-house furniture instead don't blame me.
As with many of these sellers it is questionable at times just what they
do actually have and where the product IS actually located. This one
On Sat, 16 May 2020 at 08:08, David Berndt wrote:
> When reasonably sized harmonic drives with servo motors inbuilt are 250$
> on ebay, they are COTS. So the answer is yes. Just buy one of those and
> move on to solving a more interesting problem or making whatever the
> machine is supposed to
I don't think so.
But have dreams of machining a big 300mm cycloidal drive myself. Large Dia
to increase rigidity and accuracy
After a point if you put any value on your time it just makes sense to go
buy a second hand cycloidal gearbox
On Sat, May 16, 2020, 6:54 PM John Dammeyer wrote:
> Hi
Harmonic drive but they are expensive.
> I've been thinking about 4th axes;
> While motorised reduction drives are readily available, the issue is
> obviously backlash.
>
> One way to make a zero backlash drive is to use two identical
> gearbox/drives. Place them at opposite ends of the axis,
Why are you particularly worried about that? Cyclodial gear boxes and
harmonic drives are both basically 0 backlash, with potentially some lost
motion. Most are repeatable well under 1 arc minute, which compared to a
lot of rotary tables already out there. And that's something like a .0017"
On Fri, 2020-05-15 at 13:40 -0500, Bari wrote:
> On 5/15/20 1:02 PM, Valerio Bellizzomi wrote:
>
> >
> > I am using 2.8 amd64, I will the instructions tomorrow and post the
> > result.
> >
> > Thanks.
> >
> Support for QTPYVCP is really great on IRC freenode #hazzy
Launching pyvcp shows error:
Greetings all;
I ask 'cuz I'm going to see if I can find out today why I can't turn the
index axle on the side much more than 1 turn and it binds, with the
locking levers on the other side all loosened a turn or so. Even that
amount of turning is quite draggy. And this came w/o anything like
On Saturday 16 May 2020 07:51:52 Valerio Bellizzomi wrote:
> On Fri, 2020-05-15 at 13:40 -0500, Bari wrote:
> > On 5/15/20 1:02 PM, Valerio Bellizzomi wrote:
> > > I am using 2.8 amd64, I will the instructions tomorrow and post
> > > the result.
> > >
> > > Thanks.
> >
> > Support for QTPYVCP is
On Sat, 16 May 2020 at 13:46, Gene Heskett wrote:
> I ask 'cuz I'm going to see if I can find out today why I can't turn the
> index axle on the side much more than 1 turn and it bind
There is an end-thrust adjustment for the worm shaft on the opposite
side of the unit.
Also, the worm shaft
On Saturday 16 May 2020 09:13:45 andy pugh wrote:
> On Sat, 16 May 2020 at 13:46, Gene Heskett
wrote:
> > I ask 'cuz I'm going to see if I can find out today why I can't turn
> > the index axle on the side much more than 1 turn and it bind
>
> There is an end-thrust adjustment for the worm
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