Re: [Emc-users] Chinese 400W AC servo + driver selection

[Tomaz T .]

Thank you for info about bergerda servos! Any idea which driver series would 
fit best with their 60SM-M0130MAL (400W AC servo)?

>
>

> From: John Dammeyer 
> Sent: Thursday, December 16, 2021 8:30 PM
> To: 'Enhanced Machine Controller (EMC)' 
> Subject: Re: [Emc-users] Chinese 400W AC servo + driver selection
>
> Hi Tomaz,
> I've moved from DC Servos with HP_UHU drivers to Bergerda 400W AC Servos on X 
> and Y, a 750W on the Knee and 1.8kW for the spindle.  Couldn't be happier 
> with price and service.  Especially  service/support.
>
> The problem with Aliexpress is you are dealing with little resellers (perhaps 
> not so little of course) but paying Alibaba and FedEx shipping for Bergerda I 
> still found the cost overall less than Ebay or Aliexpress.  And there's the 
> service.
>
> http://en.bergerda.com/product/607.html
>
> Be prepared for larger than normal motor shafts, 220VAC operation.  The 
> contact is Donald Chen.
>
> John Dammeyer
>
>> -Original Message-
>> From: Tomaz T. [mailto:tomaz_...@hotmail.com]
>> Sent: December-16-21 11:28 AM
>> To: emc-users
>> Subject: [Emc-users] Chinese 400W AC servo + driver selection
>>
>> Anyone here has experience with cheap Chinese 400W AC servos (and drivers) 
>> from aliexpress. Which combination to choose for on
>> "non commercial" cnc router!? There are so many of them and not much reviews 
>> to find ...
>>
>>
>>
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users



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Re: [Emc-users] Chinese 400W AC servo + driver selection

[John Dammeyer]

Tomaz,
Here's a link to a short (really short) video showing the 400W motor on the X 
axis.
https://youtu.be/43liAVILgHY

I only ever made a video of the system running with the Z axis Knee changed to 
the 750W motor.   In that video you can see the X still has the brushed DC 
Servo which ultimately gave so much trouble I switched over to the 400W AC 
servos.  Even a 1200 oz-in stepper motor with Gecko Drive could not do more 
that 25 ipm on the knee.  The Bergerda gives me over 120 ipm which is way too 
fast for me if something goes wrong.  I've not yet gotten to the ESTOP in time.
https://youtu.be/I6lvnYhlez4

I'll see what I've got in my LCNC G-Code folder and make a video of all 4 
Bergerda  AC motor/drives doing something.

Oh.  And Donald Chen once told me the difference between their AC servos and 
some of the others sold on Aliexpress etc. was the encoder.  They used an 
expensive Japanese one and he implied some of their cheaper competition used 
Chinese ones that weren't great.

So of course the first thing I did was remove the back cover on the motor to 
look for labels.  Sure enough.  Japanese and I think in the $80 range and up 
IIRC.

John

> -Original Message-
> From: Tomaz T. [mailto:tomaz_...@hotmail.com]
> Sent: December-16-21 11:28 AM
> To: emc-users
> Subject: [Emc-users] Chinese 400W AC servo + driver selection
> 
> Anyone here has experience with cheap Chinese 400W AC servos (and drivers) 
> from aliexpress. Which combination to choose for on
> "non commercial" cnc router!? There are so many of them and not much reviews 
> to find ...
> 
> 
> 
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Re: [Emc-users] LinuxCNC 2.8 Downloads

[John Dammeyer]

I clicked on that link and had no problem downloading it.  I now have both 
2.8.0 and 2.8.2 in my downloads folder.

Is it failing when you try and install?
John


> -Original Message-
> From: R C [mailto:cjv...@gmail.com]
> Sent: December-16-21 5:42 PM
> To: linuxcnc-users-list
> Subject: [Emc-users] LinuxCNC 2.8 Downloads
> 
> Hello,
> 
> 
> I am trying to download� linuxcnc 2.8 (or the newest version)
> 
> 
> 
> when I try to download the "LinuxCNC 2.8.2 Debian 10 Buster PREEMPT-RT
> ISO "� I get
> 
> "/tmp/0Pe2bVnE.part could not be saved, because the source file could
> not be read.
> 
> Try again later, or contact the server administrator."
> 
> 
> It also says (on the page)� that the RTAI kernel might be better?
> 
> 
> 
> So what is the best way to� install a LinuxCNC 2.8.2 iso/package ?
> 
> 
> thanks,
> 
> 
> Ron
> 
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Re: [Emc-users] Chinese 400W AC servo + driver selection

[Leonardo Marsaglia]

Hi Tomaz,

I've purchased some servo motors from the RTelligent brand. Pretty good
ones but I only tested it so far. The manuals are clear and the drives and
motors are really well built. As Todd recommended, it's better to purchase
the entire set from one seller.

El jue, 16 dic 2021 a las 17:35, John Dammeyer ()
escribió:

> Hi Tomaz,
> I've moved from DC Servos with HP_UHU drivers to Bergerda 400W AC Servos
> on X and Y, a 750W on the Knee and 1.8kW for the spindle.  Couldn't be
> happier with price and service.  Especially service/support.
>
> The problem with Aliexpress is you are dealing with little resellers
> (perhaps not so little of course) but paying Alibaba and FedEx shipping for
> Bergerda I still found the cost overall less than Ebay or Aliexpress.  And
> there's the service.
>
> http://en.bergerda.com/product/607.html
>
> Be prepared for larger than normal motor shafts, 220VAC operation.  The
> contact is Donald Chen.
>
> John Dammeyer
>
> > -Original Message-
> > From: Tomaz T. [mailto:tomaz_...@hotmail.com]
> > Sent: December-16-21 11:28 AM
> > To: emc-users
> > Subject: [Emc-users] Chinese 400W AC servo + driver selection
> >
> > Anyone here has experience with cheap Chinese 400W AC servos (and
> drivers) from aliexpress. Which combination to choose for on
> > "non commercial" cnc router!? There are so many of them and not much
> reviews to find ...
> >
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
>
>
> ___
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> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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[Emc-users] LinuxCNC 2.8 Downloads

[R C]

Hello,


I am trying to download  linuxcnc 2.8 (or the newest version)



when I try to download the "LinuxCNC 2.8.2 Debian 10 Buster PREEMPT-RT 
ISO "  I get


"/tmp/0Pe2bVnE.part could not be saved, because the source file could 
not be read.


Try again later, or contact the server administrator."


It also says (on the page)  that the RTAI kernel might be better?



So what is the best way to  install a LinuxCNC 2.8.2 iso/package ?


thanks,


Ron

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Re: [Emc-users] Harmonic Drive

[gene heskett]

On Thursday, December 16, 2021 5:03:10 PM EST John Dammeyer wrote:
> > From: gene heskett [mailto:ghesk...@shentel.net]
> > Subject: Re: [Emc-users] Harmonic Drive
> > 
> > On Thursday, December 16, 2021 1:10:30 PM EST John Dammeyer wrote:
> > > A pencil line on both outer ring gears.  The Blue 100 gear held tight. 
> > > Turn the Red Planetary cluster shaft and the Green 101 gear turns
> > > slowly.> 
> > Sweet John. Can you show us a pix from the blue side?  And are the top and
> > bottom pinions the same tooth count with the difference in the outer rings
> > only?
> > 
> > Thanks John. I am encouraged to see if I can make a smaller one when my
> > printer is working again.
> > 
> > > > From: Todd Zuercher [mailto:to...@pgrahamdunn.com]
> > > > 
> > > > 19tooth, 1.25module "should" be the right size sun gear for the 101/41
> > > > gear set, and 20tooth would be the one for the 100/40 set.
> 
> Hi Gene,
> As Todd mentioned, 100/40 for the blue and 101/41 for the green.
> 
> Now that I've beveled the gears (should have been done while printing) they
> no longer run into the other ring which I also beveled I'm not sure the
> system is actually working.   It seems like the 101/41 set wants to skip a
> tooth every little while.  But I don't know if that's because the spider is
> too flexible or because I'm trying to hold onto everything while I turn it.
>  The outer gears appear to want to wobble too.  Could just be too tight a
> mesh from the 3D printing side of things.

My guess is that the spider is too willowy, see my comments in the previous 
post to Todd about how to stiffen it up by making it as two rings with a 
bolthole thru the pillar, in the gap just outside of the pinion teeth. the 
trick is to keep the pinion shafts dead vertical between the rings by locking 
the rings together. 

It could also be that the pinions are out of time with each other, perhaps a 
printed in marker at the exact both sets of teeth are aligned point to help 
when inserting the pinions on the shaft, with the marker being used to 
establish the correct timing? Piece of cake if there are 3 pinions and a 3 
tooth diff in the ring gears, they all point east at the same time. But thats 
not what you have. pinion timing correct would be when its running, zero 
wobble of either the spider rings OR the output, moving ring when everything 
is in time. And there is one correct, and n! ways it could be wrong. Make the 
marks, it couldn't hurt. And with 3 pinions, each with 40 or 41 teeth, n! is 
well out of range of my elderly SR-51 as it only has a 2 digit exponent.

I have a gnawing feeling in the back of my mind that with three pinions, you 
need a three tooth diff in the ring gear tooth count. But I'm hoping I'm wrong.

> Oh and beveling was done by chucking up a piece of casting sprue, turning it
> to 20mm and drilling tapping a 1/4-20 hole.  Slide on the gear, clamp with
> fender washer and bolt.   I ran a 30 degree bevel on the compound and then
> used a dirty wire brush with the lathe stopped to clean out the bits of
> plastic hanging on.
> 
> Previously the gears had all been reamed with one of those expandable
> reamers and the spider posts sanded and smoothed to the gears spin freely
> without any play.
> 
> John


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





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Re: [Emc-users] Harmonic Drive

[John Dammeyer]

In Alibre it's a python script and the function AddGearNP appears to need Pitch 
Diameter .
==
# default settings
NumberofTeeth = 20
PitchDiameter = 30
PressureAngle = 20
Thickness = 3

Win = Windows()

ScriptName = 'Gear Generator'

# create dialog window and show to user
Options = []
Options.append([None, WindowsInputTypes.Image, 'GearGenerator.png', 170])
Options.append(['Number of Teeth', WindowsInputTypes.Integer, NumberofTeeth])
Options.append(['Pitch Diameter (mm)', WindowsInputTypes.Real, PitchDiameter])
Options.append(['Pressure Angle', WindowsInputTypes.Real, PressureAngle])
Options.append(['Thickness (mm)', WindowsInputTypes.Real, Thickness])
Values = Win.OptionsDialog(ScriptName, Options, 170)
if Values == None:
  sys.exit()

print "Working..."

# get user inputs
NumberofTeeth = Values[1]
PitchDiameter = Values[2]
PressureAngle = Values[3]
Thickness = Values[4]

# get current part
MyPart = CurrentPart()

# get the plane to create the gear on
GearPlane = MyPart.XYPlane

# create the sketch then extrude it
ProfileSketch = MyPart.AddGearNP("Profile", NumberofTeeth, PitchDiameter, 
PressureAngle, 0, 0, False, GearPlane)
Gear = MyPart.AddExtrudeBoss("Gear", ProfileSketch, Thickness, False)

print "Done"

Now if I add Module as a parameter, and into the dialog and then test on 
PitchDiameter == 0 then I can create PitchDiameter from the number of teeth and 
the module.

Next add the bearing reliefs, alignment holes and bevels on the teeth and bingo 
a new 40T gear.

That took 15 minutes.  But now I can use Module with Alibre.

John


> -Original Message-
> From: Gregg Eshelman via Emc-users [mailto:emc-users@lists.sourceforge.net]
> Sent: December-16-21 3:20 PM
> To: Enhanced Machine Controller (EMC)
> Cc: Gregg Eshelman
> Subject: Re: [Emc-users] Harmonic Drive
> 
> Dunno why every CAD program with a gear wizard, generator etc doesn't do 
> both. https://evolventdesign.com/pages/pitch-
> calculator
> 
> 
>On Thursday, December 16, 2021, 12:56:53 AM MST, John Dammeyer 
>  wrote:
> 
>  The AlibreCAM Gear generator doesn't accept module.� Instead it wants number 
> of teeth and pitch diameter.�
> 
> So I whipped up a spreadsheet that converts say the module 1.25 that Todd 
> used and chose 19 teeth for the sun gear.� That appears
> to be the right size pitch diameter for the test setup.� At least when I 
> check it out with my calipers.� But of course 19T don't fit.� It
> has to be 20T and that then physically doesn't fit.�
> 
> So creating a true planetary set with all the gears fitting appears to be a 
> bit more difficult.
> 
> John
> 
> 
> 
> > -Original Message-
> > From: Gregg Eshelman via Emc-users [mailto:emc-users@lists.sourceforge.net]
> > Sent: December-15-21 8:22 PM
> > To: Enhanced Machine Controller (EMC)
> > Cc: Gregg Eshelman
> > Subject: Re: [Emc-users] Harmonic Drive
> >
> > Does FreeCAD's gear wizard support both Diametral Pitch and Module gears 
> > now?
> >
> >
> >� � On Wednesday, December 15, 2021, 04:36:00 PM MST, John Dammeyer 
> > wrote:
> >
> >� I still haven't been able to make a simple circle in FreeCAD.? I keep 
> >looking for the Alibre way of doing it which for my brain has
> > always been close to perfect.? Never could use AutoCAD and I find Fusion360 
> > confusing .
> > However the gear tool is quite nice in FreeCAD.
> >
> > I'm still having some problem visualizing exactly how the gears turn to 
> > create 67:1.? So I thought I'd blow a bunch of money on
> > filament and print them.? In hindsight I should have expanded the pinion 
> > holes to 22mm since that's a standard (cheap) bearing
> size.
> >
> > Too late now.? Just over 2 hours before the other 4 are done.? I could make 
> > some tubes that hold smaller diameter ones.? ? Or
> just
> > play with the motion here first.? See how it works and then decide if I 
> > want to use my module 1.0mm cutters to make them out of
> > metal.
> >
> > Or just print ones with inset relief to hold 8x22x7 standard bearings.
> > John
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Re: [Emc-users] Harmonic Drive

[gene heskett]

On Thursday, December 16, 2021 5:03:12 PM EST Todd Zuercher wrote:
> The pinion pairs are 1 tooth different in size (40 and 41).  I think If I
> were printing them I would print them as one piece instead of screwing them
> together.  All three sets of pinions on the triple pinion design, would use
> the same angular offsets so all 3 pairs of pinion gears would be identical.
>  All of the gears use the same module.  As to the overall size it is 6"
> diameter and less than 2" tall.  Other changes I would incorporate would be
> adding a ball bearing between the carrier shafts and the pinions.  

Definitely on the todo list but it raises the cost considerably. What I have 
now can be duped if it breaks, for around a tenner, Only bearings are crosman 
BB's with printed races. $17 for a big 6000 count bottle. PETG at $22/kg roll.
By using a 3 phase motor that comes with an 8mm shaft I grind for a much 
bigger Dflat, no metallic hub, just drive it onto the motor shaft, done.

> I have no idea how much scaling down would affect the strength of it.   Or
> even the overall strength of printed gear sets in general.  So which tends
> to be stronger printed in plastic larger or smaller gear teeth.
 
I'm in that same boat called curious.

Scaling the teeth down also puts more of then in contact so I suspect its 
probably a wash, Using an eccentric armature idealizes the contact impact by 
having double the teeth in contact at the same time which should also lengthen 
the service life. The weak point there is the outer race that transfers the 
eccentricity of the armature to the inside, smooth face of the loose belt, the 
wave generator in this parlance. I'm using a loose belt with 60 splines, and 
my internal gears are 60 and 62 teeth, So my gear ratio is 30/-1. I have code 
in my hal file which can measure the scale to about 2 places right of the 
decimal point so I can drive it to about 3 arc-minutes of accuracy,

And so far I have used triangles as the splines with a height of around 3mm 
because they render fairly accurately on my printer.  That probably results in 
a higher wear rate than a true involute gear due to the increased sliding. Its 
good to clip the tips about 10% to keep them from bottoming against the fillet 
the printer leaves behind where two triangle bases meet.

OTOH one of those has now been running at about 300 revs input speed since the 
last week of september, sitting on the kitchen counter. No load because I 
knocked the output gear loose trying to make a fixed length belt work with one 
too many teeth. This A drive has no provision to move either shaft to tighten 
the belt, and not enough room to add a tensioning idler. So I'm going to see 
if there is a magic combo of teeth that will result in a tight enough belt. 23 
on the drive and 83 on the chuck axle leaves quite a bit of backlash, but a 24 
tooth on the drive was torn out. If push comes to shove, at 60 teeth on the 
load pulley it will be some smaller, and I will then have room to build an 
idler pulley & bracket to tighten the belt to just right..

With the 3 or 4 pinion model I think I'd make the pinion carrier in two pieces 
in order to brace the tops of the posts better since they will want to put the 
two rings out of phase so some sort of a pillar to lock the top and bottom 
rings together should be printed to join the rings in the outer gap between 
the pinions. That would hold the pinion axles vertical even when its loaded to 
near its breaking point. The pinion carrier itself should float between the sun 
and outer rings, no bearings except maybe a axial thrust washer/spacer, some 
sort of a greased fiber. enough to contain any axial thrust and keep the 
outside edges of the rings from dragging on the housings,

> Also different numbers of teeth are possible and still work out to mesh
> correctly and can change the overall output ratio.  I did a layout with
> 1.00 module gears 125/126 tooth rings and 50/51 tooth pinions and it all
> meshes the same and is the same overall dimensions as the version that John
> printed.  This change increased the output ratio to 84:1.
 
> I'm very curious how strong this actually is and where the weak points might
> be.

Some guesses, possibly wrong, above.
 
Take care and stay well, Todd.
> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street 
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031

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





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Re: [Emc-users] Harmonic Drive

[Gregg Eshelman via Emc-users]

Dunno why every CAD program with a gear wizard, generator etc doesn't do both. 
https://evolventdesign.com/pages/pitch-calculator


   On Thursday, December 16, 2021, 12:56:53 AM MST, John Dammeyer 
 wrote:  
 
 The AlibreCAM Gear generator doesn't accept module.  Instead it wants number 
of teeth and pitch diameter.  

So I whipped up a spreadsheet that converts say the module 1.25 that Todd used 
and chose 19 teeth for the sun gear.  That appears to be the right size pitch 
diameter for the test setup.  At least when I check it out with my calipers.  
But of course 19T don't fit.  It has to be 20T and that then physically doesn't 
fit.  

So creating a true planetary set with all the gears fitting appears to be a bit 
more difficult.

John



> -Original Message-
> From: Gregg Eshelman via Emc-users [mailto:emc-users@lists.sourceforge.net]
> Sent: December-15-21 8:22 PM
> To: Enhanced Machine Controller (EMC)
> Cc: Gregg Eshelman
> Subject: Re: [Emc-users] Harmonic Drive
> 
> Does FreeCAD's gear wizard support both Diametral Pitch and Module gears now?
> 
> 
>    On Wednesday, December 15, 2021, 04:36:00 PM MST, John Dammeyer 
> wrote:
> 
>  I still haven't been able to make a simple circle in FreeCAD.� I keep 
>looking for the Alibre way of doing it which for my brain has
> always been close to perfect.� Never could use AutoCAD and I find Fusion360 
> confusing .
> However the gear tool is quite nice in FreeCAD.
> 
> I'm still having some problem visualizing exactly how the gears turn to 
> create 67:1.� So I thought I'd blow a bunch of money on
> filament and print them.� In hindsight I should have expanded the pinion 
> holes to 22mm since that's a standard (cheap) bearing size.
> 
> Too late now.� Just over 2 hours before the other 4 are done.� I could make 
> some tubes that hold smaller diameter ones.� � Or just
> play with the motion here first.� See how it works and then decide if I want 
> to use my module 1.0mm cutters to make them out of
> metal.
> 
> Or just print ones with inset relief to hold 8x22x7 standard bearings.
> John  
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Re: [Emc-users] Harmonic Drive

[Todd Zuercher]

The pinion pairs are 1 tooth different in size (40 and 41).  I think If I were 
printing them I would print them as one piece instead of screwing them 
together.  All three sets of pinions on the triple pinion design, would use the 
same angular offsets so all 3 pairs of pinion gears would be identical.  All of 
the gears use the same module.  As to the overall size it is 6" diameter and 
less than 2" tall.  Other changes I would incorporate would be adding a ball 
bearing between the carrier shafts and the pinions.  

I have no idea how much scaling down would affect the strength of it.   Or even 
the overall strength of printed gear sets in general.  So which tends to be 
stronger printed in plastic larger or smaller gear teeth.

Also different numbers of teeth are possible and still work out to mesh 
correctly and can change the overall output ratio.  I did a layout with 1.00 
module gears 125/126 tooth rings and 50/51 tooth pinions and it all meshes the 
same and is the same overall dimensions as the version that John printed.  This 
change increased the output ratio to 84:1.

I'm very curious how strong this actually is and where the weak points might be.

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

-Original Message-
From: gene heskett  
Sent: Thursday, December 16, 2021 3:48 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Harmonic Drive

[EXTERNAL EMAIL] Be sure links are safe.

On Thursday, December 16, 2021 1:10:30 PM EST John Dammeyer wrote:
> A pencil line on both outer ring gears.  The Blue 100 gear held tight.  
> Turn the Red Planetary cluster shaft and the Green 101 gear turns slowly.
>
> The assembly needs better mounting before backlash can be verified.  
> This design does look like it would be functional with a smaller 0.5 
> module gear set with the ring gear holding at least 135T so that the 
> 'rack' cutter can be used.  Largest set I have is 1.0module.
>
> I'm waiting for the Size 32 Chuck and collet set to connect onto my 
> brand name Harmonic Drive which is already connected as the 4th axis 
> for my LCNC system.  It will be interesting to see if I can design a powered 
> tool to
> hold the cutter for milling the ring gears.   And maybe upgrade my pattern
> for the Harmonic Drive to allow horizontal mounting.  Something Andy 
> doesn't need because he's got the horizontal mill.
>
> Meanwhile, figure out how to mount this huge monstrosity.
>
> John

Sweet John. Can you show us a pix from the blue side?  And are the top and 
bottom pinions the same tooth count with the difference in the outer rings only?

Thanks John. I am encouraged to see if I can make a smaller one when my printer 
is working again.
>
> > -Original Message-
> > From: Todd Zuercher [mailto:to...@pgrahamdunn.com]
> > Sent: December-16-21 8:19 AM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Harmonic Drive
> >
> > DP is just the invers of module.
> >
> > 19tooth, 1.25module "should" be the right size sun gear for the 
> > 101/41 gear set, and 20tooth would be the one for the 100/40 set. 
> > But using them as ordinary planetary sets only gives a max gear 
> > ratio of about 37.9 to one running them compounded (6:1 * 6.316:1) 
> > Here is a nice site for playing with ordinary planetary gear sets.
> > https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww
> > .thecatalystis.com%2Fgears%2F&data=04%7C01%7Ctoddz%40pgrahamdunn
> > .com%7Ccf2a5ffcb0c744d46d1608d9c0d5999d%7C5758544c573f47cebee96c3e08
> > 06fb43%7C0%7C0%7C637752846476293126%7CUnknown%7CTWFpbGZsb3d8eyJWIjoi
> > MC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&am
> > p;sdata=jnRxmKvnfucjWz7k9Fl8oGZgKX2iDoMcug7I0SZ4zP0%3D&reserved=
> > 0
> >
> > However adding a sun gear to the input side of the original idea to 
> > turn the planet carrier instead of turning the carrier directly, 
> > might be a good idea (If you want huge gear reduction).  That would 
> > add a 6:1 gear reduction multiplying the reduction significantly. 
> > (End result would be a whopping 404:1 gear reduction.)  Holy crap 
> > that might just be getting a little out of hand.  (How much 
> > reduction were we after in the beginning?)
> >
> > Here is a website that has the mathematical formulas for calculating 
> > a whole bunch of planetary gear arrangements.  Including the two we 
> > are talking about here.  The original idea is case#13 and this new 
> > one with the added sun gear input is case#15.
> > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fww
> > w.engineersedge.com%2Fgears%2Fplanetary_epicyclic_gear_13736.htm&
> > ;data=04%7C01%7Ctoddz%40pgrahamdunn.com%7Ccf2a5ffcb0c744d46d1608d9c0
> > d5999d%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C6377528464762931
> > 26%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBT
> > iI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=AgDIT6T6W7LpgBRzSsaONGBPz
> > fMl%2FsBDWdCxzDaH

Re: [Emc-users] Harmonic Drive

[gene heskett]

On Thursday, December 16, 2021 1:10:30 PM EST John Dammeyer wrote:
> A pencil line on both outer ring gears.  The Blue 100 gear held tight.  Turn
> the Red Planetary cluster shaft and the Green 101 gear turns slowly.
> 
> The assembly needs better mounting before backlash can be verified.  This
> design does look like it would be functional with a smaller 0.5 module gear
> set with the ring gear holding at least 135T so that the 'rack' cutter can
> be used.  Largest set I have is 1.0module.
> 
> I'm waiting for the Size 32 Chuck and collet set to connect onto my brand
> name Harmonic Drive which is already connected as the 4th axis for my LCNC
> system.  It will be interesting to see if I can design a powered tool to
> hold the cutter for milling the ring gears.   And maybe upgrade my pattern
> for the Harmonic Drive to allow horizontal mounting.  Something Andy
> doesn't need because he's got the horizontal mill.
> 
> Meanwhile, figure out how to mount this huge monstrosity.
> 
> John

Sweet John. Can you show us a pix from the blue side?  And are the top and 
bottom pinions the same tooth count with the difference in the outer rings 
only?

Thanks John. I am encouraged to see if I can make a smaller one when my 
printer is working again.
> 
> > -Original Message-
> > From: Todd Zuercher [mailto:to...@pgrahamdunn.com]
> > Sent: December-16-21 8:19 AM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Harmonic Drive
> > 
> > DP is just the invers of module.
> > 
> > 19tooth, 1.25module "should" be the right size sun gear for the 101/41
> > gear set, and 20tooth would be the one for the 100/40 set. But using them
> > as ordinary planetary sets only gives a max gear ratio of about 37.9 to
> > one running them compounded (6:1 * 6.316:1) Here is a nice site for
> > playing with ordinary planetary gear sets.
> > http://www.thecatalystis.com/gears/
> > 
> > However adding a sun gear to the input side of the original idea to turn
> > the planet carrier instead of turning the carrier directly, might be a
> > good idea (If you want huge gear reduction).  That would add a 6:1 gear
> > reduction multiplying the reduction significantly. (End result would be a
> > whopping 404:1 gear reduction.)  Holy crap that might just be getting a
> > little out of hand.  (How much reduction were we after in the beginning?)
> > 
> > Here is a website that has the mathematical formulas for calculating a
> > whole bunch of planetary gear arrangements.  Including the two we are
> > talking about here.  The original idea is case#13 and this new one with
> > the added sun gear input is case#15.
> > https://www.engineersedge.com/gears/planetary_epicyclic_gear_13736.htm
> > 
> > 
> > Todd Zuercher
> > P. Graham Dunn Inc.
> > 630 Henry Street
> > Dalton, Ohio 44618
> > Phone:� (330)828-2105ext. 2031
> > 
> > -Original Message-
> > From: John Dammeyer 
> > Sent: Thursday, December 16, 2021 2:54 AM
> > To: 'Enhanced Machine Controller (EMC)' 
> > Subject: Re: [Emc-users] Harmonic Drive
> > 
> > [EXTERNAL EMAIL] Be sure links are safe.
> > 
> > The AlibreCAM Gear generator doesn't accept module.  Instead it wants
> > number of teeth and pitch diameter.
> > 
> > So I whipped up a spreadsheet that converts say the module 1.25 that Todd
> > used and chose 19 teeth for the sun gear.  That appears to be the right
> > size pitch diameter for the test setup.  At least when I check it out
> > with my calipers.  But of course 19T don't fit.  It has to be 20T and
> > that then physically doesn't fit.
> > 
> > So creating a true planetary set with all the gears fitting appears to be
> > a bit more difficult.
> > 
> > John
> > 
> > > -Original Message-
> > > From: Gregg Eshelman via Emc-users
> > > [mailto:emc-users@lists.sourceforge.net]
> > > Sent: December-15-21 8:22 PM
> > > To: Enhanced Machine Controller (EMC)
> > > Cc: Gregg Eshelman
> > > Subject: Re: [Emc-users] Harmonic Drive
> > > 
> > > Does FreeCAD's gear wizard support both Diametral Pitch and Module gears
> > > now?> > 
> > > On Wednesday, December 15, 2021, 04:36:00 PM MST, John Dammeyer 
 wrote:
> > >  I still haven't been able to make a simple circle in FreeCAD.  I keep
> > > 
> > > looking for the Alibre way of doing it which for my brain has always
> > > been close to perfect.  Never could use AutoCAD and I find> 
> > Fusion360 confusing .
> > 
> > > However the gear tool is quite nice in FreeCAD.
> > > 
> > > I'm still having some problem visualizing exactly how the gears turn
> > > to create 67:1.  So I thought I'd blow a bunch of money on filament and
> > > print them.  In hindsight I should have expanded the pinion> 
> > holes to 22mm since that's a standard (cheap) bearing size.
> > 
> > > Too late now.  Just over 2 hours before the other 4 are done.  I could
> > > make some tubes that hold smaller diameter ones.Or just play with
> > > the motion here first.  See how it works and then decide if I want to
> > > use my module 1.0m

Re: [Emc-users] Chinese 400W AC servo + driver selection

[John Dammeyer]

Hi Tomaz,
I've moved from DC Servos with HP_UHU drivers to Bergerda 400W AC Servos on X 
and Y, a 750W on the Knee and 1.8kW for the spindle.  Couldn't be happier with 
price and service.  Especially service/support.

The problem with Aliexpress is you are dealing with little resellers (perhaps 
not so little of course) but paying Alibaba and FedEx shipping for Bergerda I 
still found the cost overall less than Ebay or Aliexpress.  And there's the 
service.

http://en.bergerda.com/product/607.html

Be prepared for larger than normal motor shafts, 220VAC operation.  The contact 
is Donald Chen.

John Dammeyer

> -Original Message-
> From: Tomaz T. [mailto:tomaz_...@hotmail.com]
> Sent: December-16-21 11:28 AM
> To: emc-users
> Subject: [Emc-users] Chinese 400W AC servo + driver selection
> 
> Anyone here has experience with cheap Chinese 400W AC servos (and drivers) 
> from aliexpress. Which combination to choose for on
> "non commercial" cnc router!? There are so many of them and not much reviews 
> to find ...
> 
> 
> 
> ___
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Re: [Emc-users] Chinese 400W AC servo + driver selection

[Mark Johnsen]

Tomaz,

If you're in the US, then DMM-Tech is a company that has been selling a
chinese drive for several years.
https://www.dmm-tech.com/multiaxissolutions2.html

Mark

On Thu, Dec 16, 2021 at 11:44 AM Tomaz T.  wrote:

> Anyone here has experience with cheap Chinese 400W AC servos (and drivers)
> from aliexpress. Which combination to choose for on "non commercial" cnc
> router!? There are so many of them and not much reviews to find ...
>
>

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Re: [Emc-users] Chinese 400W AC servo + driver selection

[Todd Zuercher]

My first recommendation, is to buy from someone who is selling the drive, motor 
and cabling as a set.  And that they offer a cable option in a length suitable 
for your application.  Making encoder cabling is a crappy job and you can 
usually get ready made cables for less than your cost for bulk cable would be.

2nd make sure your chosen supplier can/will ship to you in a reasonable time.  

3rd if you are inexperienced with configuring a servo.  Be sure to choose a 
supplier who can provide you with at least a little support.  Most cheap 
Chinese gear will come with pathetic auto translated documentation, that is 
just this side of useless couple that with no support and it can make things 
hard.

As to a specific recommendation, sorry I don't have any personal experience 
using one of these.  The 400w servos I set up were used motors and some older 
new old stock Technic drives bought separately and cobbled together.  They were 
decent drives with good documentation (with USA originated documentation.)  But 
it was a struggle tracking down info and specs on the motors and programming 
the drives to work with them and making cabling.  (Learn from my mistakes.)

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

-Original Message-
From: Tomaz T.  
Sent: Thursday, December 16, 2021 2:28 PM
To: emc-users 
Subject: [Emc-users] Chinese 400W AC servo + driver selection

[EXTERNAL EMAIL] Be sure links are safe.

Anyone here has experience with cheap Chinese 400W AC servos (and drivers) from 
aliexpress. Which combination to choose for on "non commercial" cnc router!? 
There are so many of them and not much reviews to find ...



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[Emc-users] Chinese 400W AC servo + driver selection

[Tomaz T .]

Anyone here has experience with cheap Chinese 400W AC servos (and drivers) from 
aliexpress. Which combination to choose for on "non commercial" cnc router!? 
There are so many of them and not much reviews to find ...



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Re: [Emc-users] Harmonic Drive

[Todd Zuercher]

DP is just the invers of module. 

19tooth, 1.25module "should" be the right size sun gear for the 101/41 gear 
set, and 20tooth would be the one for the 100/40 set.  But using them as 
ordinary planetary sets only gives a max gear ratio of about 37.9 to one 
running them compounded (6:1 * 6.316:1) Here is a nice site for playing with 
ordinary planetary gear sets.
http://www.thecatalystis.com/gears/

However adding a sun gear to the input side of the original idea to turn the 
planet carrier instead of turning the carrier directly, might be a good idea 
(If you want huge gear reduction).  That would add a 6:1 gear reduction 
multiplying the reduction significantly. (End result would be a whopping 404:1 
gear reduction.)  Holy crap that might just be getting a little out of hand.  
(How much reduction were we after in the beginning?)

Here is a website that has the mathematical formulas for calculating a whole 
bunch of planetary gear arrangements.  Including the two we are talking about 
here.  The original idea is case#13 and this new one with the added sun gear 
input is case#15.
https://www.engineersedge.com/gears/planetary_epicyclic_gear_13736.htm


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

-Original Message-
From: John Dammeyer 
Sent: Thursday, December 16, 2021 2:54 AM
To: 'Enhanced Machine Controller (EMC)' 
Subject: Re: [Emc-users] Harmonic Drive

[EXTERNAL EMAIL] Be sure links are safe.

The AlibreCAM Gear generator doesn't accept module.  Instead it wants number of 
teeth and pitch diameter.

So I whipped up a spreadsheet that converts say the module 1.25 that Todd used 
and chose 19 teeth for the sun gear.  That appears to be the right size pitch 
diameter for the test setup.  At least when I check it out with my calipers.  
But of course 19T don't fit.  It has to be 20T and that then physically doesn't 
fit.

So creating a true planetary set with all the gears fitting appears to be a bit 
more difficult.

John



> -Original Message-
> From: Gregg Eshelman via Emc-users
> [mailto:emc-users@lists.sourceforge.net]
> Sent: December-15-21 8:22 PM
> To: Enhanced Machine Controller (EMC)
> Cc: Gregg Eshelman
> Subject: Re: [Emc-users] Harmonic Drive
>
> Does FreeCAD's gear wizard support both Diametral Pitch and Module gears now?
>
>
> On Wednesday, December 15, 2021, 04:36:00 PM MST, John Dammeyer 
>  wrote:
>
>  I still haven't been able to make a simple circle in FreeCAD.  I keep 
> looking for the Alibre way of doing it which for my brain has always been 
> close to perfect.  Never could use AutoCAD and I find Fusion360 confusing .
> However the gear tool is quite nice in FreeCAD.
>
> I'm still having some problem visualizing exactly how the gears turn 
> to create 67:1.  So I thought I'd blow a bunch of money on filament and print 
> them.  In hindsight I should have expanded the pinion holes to 22mm since 
> that's a standard (cheap) bearing size.
>
> Too late now.  Just over 2 hours before the other 4 are done.  I could 
> make some tubes that hold smaller diameter ones.Or just play with 
> the motion here first.  See how it works and then decide if I want to use my 
> module 1.0mm cutters to make them out of metal.
>
> Or just print ones with inset relief to hold 8x22x7 standard bearings.
> John
>
>
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> ddz%40pgrahamdunn.com%7Cf0e23e2e0c474d89921808d9c069626e%7C5758544c573
> f47cebee96c3e0806fb43%7C0%7C0%7C637752381126836342%7CUnknown%7CTWFpbGZ
> sb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3
> D%7C3000&sdata=shhlXkCPj8ytCzxNUeNa5HZ3iPpEdTfuiLFMIzxvPhU%3D&
> reserved=0

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Re: [Emc-users] Harmonic Drive

[gene heskett]

On Thursday, December 16, 2021 6:50:01 AM EST grumpy via Emc-users wrote:
> this man's work might be helpful
> https://www.youtube.com/c/Skyentific

I don't see a dl link, so I assume he is selling it if you join his support 
channel? 

But while its nice, its too big. The crossed rollers for bearings should be 
better than the BB's I used, but they also take up lots more room.

Food for thought.

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





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Re: [Emc-users] Harmonic Drive

[grumpy via Emc-users]

this man's work might be helpful
https://www.youtube.com/c/Skyentific
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