Re: [Emc-users] Problem with Rigid Tapping on USC Equipped Bridgeport

[Scott Harwell via Emc-users]

 I would swap A phase with B phase this should correct count direction.
Scott H

On Sunday, July 19, 2020, 6:16:57 PM CDT, Jon Elson 
 wrote:  
 
 On 07/19/2020 03:59 PM, Matthew Herd wrote:
> Hi all,
>
> I made my first attempt at using spindle synchronized motion for a rigid 
> tapping operation on my Bridgeport BOSS mill today and it didn’t go as 
> planned.  It has a spindle encoder and a Pico USC board.  I can use the 
> spindle to read encoder counts and spindle position (I already use PYVCP to 
> show me spindle speed).  However, G33.1 produces unusual results and doesn’t 
> seem to work properly.  It appears that the down feed works properly, but the 
> spindle either never reverses or reverses very slowly and the synchronized 
> motion on retract doesn’t appear to reliably track the spindle motion.  In 
> several tests, it either retracts while still turning clockwise, appears to 
> retract faster than the counter-clockwise speed would allow, or just doesn’t 
> retract at all.  According to the g code reference page, 
> motion.spindle-at-speed and encoder.n.phase-Z must be connected in HAL.  I 
> don’t have spindle-at-speed hooked up, but am using rigid tapping sample HAL 
> from Pico Systems, with the encoder connected to motion.spindle-revs.
encoder.n.phase-Z does not exist on the Pico boards.  Z 
(index) cannot be seen directly, it can only be detected by 
index-enable going from true to false, and the encoder 
position count going to zero.

Wow.  First, make sure that the value fed to scale the 
spindle encoder is correct.  It should be equal to the 
number of quadrature counts/rev of the spindle (4X the 
number of "lines" on the encoder). It should look something 
like this:
setp ppmc.0.encoder.03.scale 6912


The connection to LinuxCNC looks like this on my system :
net spindle-pos  ppmc.0.encoder.03.position  spindle.0.revs


The names might have been changed in newer versions.

You should look at ppmc.0.encoder.03.velocity with Halscope 
(or even Halmeter) to make sure this signal is properly 
registering the spindle rotation.  With the correct scaling 
factor, velocity should equal 60 at 3600 RPM (60 
revs/second) and ppmc.0.encoder.03.position should count up 
at 60 counts/second.
If the velocity shows negative when the spindle is running 
"forward" then change the arithmetic sign of the encoder 
scale to a minus number.  The velocity should show an 
opposite sign when the spindle direction is reversed, and 
the position should count in the opposite direction.  If 
not, something is quite wrong with the encoder or how it is 
connected.


> I attempted to troubleshoot using this references:
> https://forum.linuxcnc.org/27-driver-boards/26275-spindle-encoder-on-pico-usc 
> 
>
> I ran a halcmd sets on the spindle index enable and it reset counts to zero 
> immediately.  spindle index enable remained false and fiddling with halscope 
> wasn’t ever successful in showing a change from false to true while playing 
> with G33 commands, etc.  I’m not sure what to try next.
>
the correct connection is :
net spindle-index-en    ppmc.0.encoder.03.index-enable 
spindle.0.index-enable

All of the above examples assume USC channel # 3 is used for 
the spindle, if different change the .03. to
whatever is needed.

The spindle index is only enabled once at the beginning of 
the spindle synchronized move.
I think the trajectory planner sets it true, and when the 
PPMC hardware detects a rising edge on the index input, it 
clears index-enable, and zeroes the position count.  So, one 
part of the system sets this bit true, and the ppmc driver 
sets it false.

In general, if the index is not working, LinuxCNC should 
hang forever waiting for index-enable to go false.  But, 
maybe if it is not hooked up at all, the behavior is different.

Jon

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[Emc-users] Need help with Bostomatic BD18-2 to linuxcnc

[Tom Smart]

I just purchased a Bostomatic BD18-2 from NASA JPL. The servo amp's for all 3 
axis were missing. I'm trying to find new amp's and information on the machine 
so i can make a linuxcnc conversion.

The motor is this glentek GM4040-41 180vdc, 9.1A. I decoded the serial number 
it has no brake, no tachometer, a special encoder, no resolver.

Identaplate shows:
GLENTEK
Model: GM4040-41-00906101-159
P/N: 3203
TORQ-IN-LB: 31.3
RES-OHMS: 0.8
RATED CURRENT: 9.1
IND-MH: 5
KV-V/kRPM: 5.6
TACH-VDC:
RATED VOLTAGE: 180VDC
MAX RPM: 3500
JA LB-IN-SEC^2: 0.0163

I've sent a request to Glentek for information on the servo and what amp's I 
would need to drive them.

I'm hoping that someone has some information on bostomatic machines maybe even 
a jackpot of a wiring diagram for the BD18-1 or BD18-2. Any wiring diagrams or 
information for bostomatic machines would probably be helpful.

Thank you for any help with this project.
Thomas

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Re: [Emc-users] found a harmonic drive set of .stl's on thingiverse

[Gene Heskett]

On Sunday 19 July 2020 20:30:35 John Dammeyer wrote:

> This may well be a dumb question Gene, but given you have the machine
> shop and CNC couldn't you make the gears etc yourself out of metal?
> John
>
Thats why I bought a BS-1, John but I'm only about $250 into motorizing 
it yet, waiting on a set of reamers ATM so I can make gearbox couplings.

> > -Original Message-
> > From: Gene Heskett [mailto:ghesk...@shentel.net]
> > Sent: July-19-20 4:59 PM
> > To: 'Enhanced Machine Controller (EMC)'
> > Subject: [Emc-users] found a harmonic drive set of .stl's on
> > thingiverse
> >
> > Greetings all;
> >
> > And I can say without fear of contradiction the openscad IS the
> > problem,
> >
> > I am current about 2mm up of a print of the outside gear of the
> > drive, and the teeth are 100% filled and very well formed so far,
> > its the best rendering I've seen on the build bed yet, so much
> > better than what openscad generates I thought my machine had been
> > swapped for a well adjusted one in the night last night. I think
> > I'll make about 3 of everything so I'll have 2 drives and a spares
> > kit.
> >
> > Biggest  problem is the 12+ hour renderiing time per piece pf this
> > first piece, and there are 2 pieces bigger yet than this one.  Now I
> > can see why some folks have a whole room full of printers. I'll be
> > two weeks making parts for three drives.
> >
> > Hopefully I can put it together correctly, there are no text files
> > and I haven't the foggiest what bearings I'll need, or what brand of
> > grease.
> >
> > 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 
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
> ___
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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] found a harmonic drive set of .stl's on thingiverse

[Gene Heskett]

On Sunday 19 July 2020 19:58:44 Gene Heskett wrote:

> Greetings all;
>
> And I can say without fear of contradiction the openscad IS the
> problem,
>
> I am current about 2mm up of a print of the outside gear of the drive,
> and the teeth are 100% filled and very well formed so far, its the
> best rendering I've seen on the build bed yet, so much better than
> what openscad generates I thought my machine had been swapped for a
> well adjusted one in the night last night. I think I'll make about 3
> of everything so I'll have 2 drives and a spares kit.
>
> Biggest  problem is the 12+ hour renderiing time per piece pf this
> first piece, and there are 2 pieces bigger yet than this one.  Now I
> can see why some folks have a whole room full of printers. I'll be two
> weeks making parts for three drives.
>
> Hopefully I can put it together correctly, there are no text files and
> I haven't the foggiest what bearings I'll need, or what brand of
> grease.
>
> Cheers, Gene Heskett

The zip contains a .step file. What does linux use to render/view that?
That file does contain the bearing part numbers, so that helps, if my 
print is rendering the correct size.

Thanks all.

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


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Re: [Emc-users] found a harmonic drive set of .stl's on thingiverse

[John Dammeyer]

This may well be a dumb question Gene, but given you have the machine shop and 
CNC couldn't you make the gears etc yourself out of metal?
John

> -Original Message-
> From: Gene Heskett [mailto:ghesk...@shentel.net]
> Sent: July-19-20 4:59 PM
> To: 'Enhanced Machine Controller (EMC)'
> Subject: [Emc-users] found a harmonic drive set of .stl's on thingiverse
> 
> Greetings all;
> 
> And I can say without fear of contradiction the openscad IS the problem,
> 
> I am current about 2mm up of a print of the outside gear of the drive,
> and the teeth are 100% filled and very well formed so far, its the best
> rendering I've seen on the build bed yet, so much better than what
> openscad generates I thought my machine had been swapped for a well
> adjusted one in the night last night. I think I'll make about 3 of
> everything so I'll have 2 drives and a spares kit.
> 
> Biggest  problem is the 12+ hour renderiing time per piece pf this first
> piece, and there are 2 pieces bigger yet than this one.  Now I can see
> why some folks have a whole room full of printers. I'll be two weeks
> making parts for three drives.
> 
> Hopefully I can put it together correctly, there are no text files and I
> haven't the foggiest what bearings I'll need, or what brand of grease.
> 
> 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 
> 
> 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users



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[Emc-users] found a harmonic drive set of .stl's on thingiverse

[Gene Heskett]

Greetings all;

And I can say without fear of contradiction the openscad IS the problem,

I am current about 2mm up of a print of the outside gear of the drive, 
and the teeth are 100% filled and very well formed so far, its the best 
rendering I've seen on the build bed yet, so much better than what 
openscad generates I thought my machine had been swapped for a well 
adjusted one in the night last night. I think I'll make about 3 of 
everything so I'll have 2 drives and a spares kit.

Biggest  problem is the 12+ hour renderiing time per piece pf this first 
piece, and there are 2 pieces bigger yet than this one.  Now I can see 
why some folks have a whole room full of printers. I'll be two weeks 
making parts for three drives.

Hopefully I can put it together correctly, there are no text files and I 
haven't the foggiest what bearings I'll need, or what brand of grease. 

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] Problem with Rigid Tapping on USC Equipped Bridgeport

[Jon Elson]

On 07/19/2020 03:59 PM, Matthew Herd wrote:

Hi all,

I made my first attempt at using spindle synchronized motion for a rigid 
tapping operation on my Bridgeport BOSS mill today and it didn’t go as planned. 
 It has a spindle encoder and a Pico USC board.  I can use the spindle to read 
encoder counts and spindle position (I already use PYVCP to show me spindle 
speed).  However, G33.1 produces unusual results and doesn’t seem to work 
properly.  It appears that the down feed works properly, but the spindle either 
never reverses or reverses very slowly and the synchronized motion on retract 
doesn’t appear to reliably track the spindle motion.  In several tests, it 
either retracts while still turning clockwise, appears to retract faster than 
the counter-clockwise speed would allow, or just doesn’t retract at all.  
According to the g code reference page, motion.spindle-at-speed and 
encoder.n.phase-Z must be connected in HAL.  I don’t have spindle-at-speed 
hooked up, but am using rigid tapping sample HAL from Pico Systems, with the 
encoder connected to motion.spindle-revs.
encoder.n.phase-Z does not exist on the Pico boards.  Z 
(index) cannot be seen directly, it can only be detected by 
index-enable going from true to false, and the encoder 
position count going to zero.


Wow.  First, make sure that the value fed to scale the 
spindle encoder is correct.  It should be equal to the 
number of quadrature counts/rev of the spindle (4X the 
number of "lines" on the encoder). It should look something 
like this:

setp ppmc.0.encoder.03.scale 6912


The connection to LinuxCNC looks like this on my system :
net spindle-pos   ppmc.0.encoder.03.position   spindle.0.revs


The names might have been changed in newer versions.

You should look at ppmc.0.encoder.03.velocity with Halscope 
(or even Halmeter) to make sure this signal is properly 
registering the spindle rotation.  With the correct scaling 
factor, velocity should equal 60 at 3600 RPM (60 
revs/second) and ppmc.0.encoder.03.position should count up 
at 60 counts/second.
If the velocity shows negative when the spindle is running 
"forward" then change the arithmetic sign of the encoder 
scale to a minus number.  The velocity should show an 
opposite sign when the spindle direction is reversed, and 
the position should count in the opposite direction.  If 
not, something is quite wrong with the encoder or how it is 
connected.




I attempted to troubleshoot using this references:
https://forum.linuxcnc.org/27-driver-boards/26275-spindle-encoder-on-pico-usc 


I ran a halcmd sets on the spindle index enable and it reset counts to zero 
immediately.  spindle index enable remained false and fiddling with halscope 
wasn’t ever successful in showing a change from false to true while playing 
with G33 commands, etc.  I’m not sure what to try next.


the correct connection is :
net spindle-index-enppmc.0.encoder.03.index-enable 
spindle.0.index-enable


All of the above examples assume USC channel # 3 is used for 
the spindle, if different change the .03. to

whatever is needed.

The spindle index is only enabled once at the beginning of 
the spindle synchronized move.
I think the trajectory planner sets it true, and when the 
PPMC hardware detects a rising edge on the index input, it 
clears index-enable, and zeroes the position count.  So, one 
part of the system sets this bit true, and the ppmc driver 
sets it false.


In general, if the index is not working, LinuxCNC should 
hang forever waiting for index-enable to go false.  But, 
maybe if it is not hooked up at all, the behavior is different.


Jon

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Re: [Emc-users] need advice, idea shoppingIOW.

[Frank Tkalcevic]

I modified some python code that is in the linuxcnc tree (author.py) and made a 
slicer post processing script that takes the generated gcode and converts line 
segments back to arcs.

https://github.com/ftkalcevic/3dPrintSmoothing

I'm constantly finding bugs, so verify your first few prints - the 
extrudeRelative variable needs to be set correctly.



-Original Message-
From: Thomas J Powderly [mailto:tjt...@gmail.com] 
Sent: Monday, 20 July 2020 12:36 AM
To: emc-users@lists.sourceforge.net
Subject: Re: [Emc-users] need advice, idea shoppingIOW.

Gene

do you want to convert a series of short lines that approximate arcs

into g02/g03, to save space?

Or, described as 'fitting x y� pairs to a circle'?


Dave E was looking for similar ( a good while back) and I didnt find any.


If you have slices that can be processed in scripts with librecad (lua)

or esdxf(python)


I imagine some batch processing, layer by layer, slogging thru your 
megafile )


For python fitting a list of coords to circle there is

https://scipy-cookbook.readthedocs.io/items/Least_Squares_Circle.html


There a classic solution by Coopes but all the papers and code I've 
found are pay for.

( I hate those 'services; that charge for such information )


theres this implementation in Javascript


https://jsxgraph.uni-bayreuth.de/wiki/index.php/Least-squares_circle_fitting


but to get the demo to render i had to wander around the site till i 
found something that did render ,

then returm :-(

once it renders, refresh the page for a new random set of points

and a new fitted circle

tomp


On 7/19/20 5:19 PM, Gene Heskett wrote:
> On Saturday 18 July 2020 22:21:20 Gregg Eshelman via Emc-users wrote:
>
>> Circa 1990: Have you heard of the new Hubble Cocktail? It's very
>> expensive, comes in a hand polished glass, and after you finish it,
>> your vision is all blurry.
>>
> ROTFLMAO!  I missed that one at the time, shame on me.
>
> Thanks Gregg.
>
> Cheers, Gene Heskett


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Re: [Emc-users] Problem with Rigid Tapping on USC Equipped Bridgeport

[andy pugh]

On Sun, 19 Jul 2020 at 22:02, Matthew Herd  wrote:

>  It appears that the down feed works properly, but the spindle either never 
> reverses or reverses very slowly and the synchronized motion on retract 
> doesn’t appear to reliably track the spindle motion.

Does the encoder count up in the clockwise direction and down in the
anticlockwise direction?

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


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[Emc-users] Problem with Rigid Tapping on USC Equipped Bridgeport

[Matthew Herd]

Hi all,

I made my first attempt at using spindle synchronized motion for a rigid 
tapping operation on my Bridgeport BOSS mill today and it didn’t go as planned. 
 It has a spindle encoder and a Pico USC board.  I can use the spindle to read 
encoder counts and spindle position (I already use PYVCP to show me spindle 
speed).  However, G33.1 produces unusual results and doesn’t seem to work 
properly.  It appears that the down feed works properly, but the spindle either 
never reverses or reverses very slowly and the synchronized motion on retract 
doesn’t appear to reliably track the spindle motion.  In several tests, it 
either retracts while still turning clockwise, appears to retract faster than 
the counter-clockwise speed would allow, or just doesn’t retract at all.  
According to the g code reference page, motion.spindle-at-speed and 
encoder.n.phase-Z must be connected in HAL.  I don’t have spindle-at-speed 
hooked up, but am using rigid tapping sample HAL from Pico Systems, with the 
encoder connected to motion.spindle-revs.

I attempted to troubleshoot using this references:
https://forum.linuxcnc.org/27-driver-boards/26275-spindle-encoder-on-pico-usc 


I ran a halcmd sets on the spindle index enable and it reset counts to zero 
immediately.  spindle index enable remained false and fiddling with halscope 
wasn’t ever successful in showing a change from false to true while playing 
with G33 commands, etc.  I’m not sure what to try next.

Thanks!
Matt
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Re: [Emc-users] need advice, idea shoppingIOW.

[Gene Heskett]

On Sunday 19 July 2020 14:24:29 andy pugh wrote:

> On Sun, 19 Jul 2020 at 19:01, Gene Heskett  
wrote:
> > > If you want rounder curves, you need to decrease the triangle size
> > > in the input STL file.
> >
> > And where do I do that in openscad?
>
> I have never used OpenSCAD. But after a bit of a Google this might be
> the answer:
> https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/The_OpenSCAD_Langua
>ge#.24fa.2C_.24fs_and_.24fn
>
> But, how did you generate the input model? If that was an STL
> originally then are you sure that the detail actually exists?

No, not stl src, usig .scad sources for the parametric sprocket package. 
I makes.stl's, then Cura renders the gcode.  But below 5mm teeth, they 
are both sparse like infill and leaning ccw instead of projecting 
straight out.

Thanks Andy.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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] need advice, idea shoppingIOW.

[andy pugh]

On Sun, 19 Jul 2020 at 19:01, Gene Heskett  wrote:

> > If you want rounder curves, you need to decrease the triangle size in
> > the input STL file.
>
> And where do I do that in openscad?

I have never used OpenSCAD. But after a bit of a Google this might be
the answer:
https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/The_OpenSCAD_Language#.24fa.2C_.24fs_and_.24fn

But, how did you generate the input model? If that was an STL
originally then are you sure that the detail actually exists?

-- 
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] need advice, idea shoppingIOW.

[andy pugh]

On Sun, 19 Jul 2020 at 19:01, Gene Heskett  wrote:

> > I only know of one slicer that outputs curves, and I wrote it :-)

> And its no doubt a better one,

No, it is extremely limited.

Cura is about the best slicer out there. I don't think that
reinventing the wheel is going to help with the problems you are
having.

-- 
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] need advice, idea shoppingIOW.

[Gene Heskett]

On Sunday 19 July 2020 11:22:17 andy pugh wrote:

> On Sun, 19 Jul 2020 at 11:20, Gene Heskett  
wrote:
> > And I have come to the conclusion that both cura and merlin that run
> > the enders need to be replaced as neither has a G2 or G3 for circles
>
> STL is a set of triangular facets. There are no curves for the slicer
> to make G2 or G3 arcs out of.
>
> If you want rounder curves, you need to decrease the triangle size in
> the input STL file.

And where do I do that in openscad?

> I only know of one slicer that outputs curves, and I wrote it :-)
> (And it works directly off the CAD model in Inventor, where curves do
> exist)

And its no doubt a better one, but not available to me without a pile of 
sheckels for Inventor.

Thanks Andy.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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] need advice, idea shoppingIOW.

[Gene Heskett]

On Sunday 19 July 2020 10:36:27 Thomas J Powderly wrote:

> Gene
>
> do you want to convert a series of short lines that approximate arcs
>
> into g02/g03, to save space?
>
> Or, described as 'fitting x y  pairs to a circle'?
>
>
> Dave E was looking for similar ( a good while back) and I didnt find
> any.
>
>
> If you have slices that can be processed in scripts with librecad
> (lua)
>
> or esdxf(python)
>
>
> I imagine some batch processing, layer by layer, slogging thru your
> megafile )
>
>
> For python fitting a list of coords to circle there is
>
> https://scipy-cookbook.readthedocs.io/items/Least_Squares_Circle.html
>
>
> There a classic solution by Coopes but all the papers and code I've
> found are pay for.
>
> ( I hate those 'services; that charge for such information )
>
>
> theres this implementation in Javascript
>
>
> https://jsxgraph.uni-bayreuth.de/wiki/index.php/Least-squares_circle_f
>itting
>
>
> but to get the demo to render i had to wander around the site till i
> found something that did render ,
>
> then returm :-(
>
> once it renders, refresh the page for a new random set of points
>
> and a new fitted circle
>
> tomp
>
I've found that slic3r can output to LCNC. And I might be able to make it 
run the result on the 6040, albeit slower because of the gantry weight. 
if I replace the spindle with an extruder assembly addressed as drive 
whatever. I'd have to rig a flat, levelable build platform and heat it 
too, but its doable, or I could probably drive the Ender-3 Pro with 
linucnc running on a pi4, its working really well on the Sheldon lathe. 
But that would be a hell of a lot of work I may not have heart enough to 
complete, they had to replace a 5 month old stent the last of May.

But before I can do that, slic3r needs to run on this machine and apt-get 
is refusing to install its gui's libwx-perl dependencies. Frustrated is 
not an adequate description. Complaining about broken dependencies but 
refusing to name the package thats breaking it.

> On 7/19/20 5:19 PM, Gene Heskett wrote:
> > On Saturday 18 July 2020 22:21:20 Gregg Eshelman via Emc-users wrote:
> >> Circa 1990: Have you heard of the new Hubble Cocktail? It's very
> >> expensive, comes in a hand polished glass, and after you finish it,
> >> your vision is all blurry.
> >
> > ROTFLMAO!  I missed that one at the time, shame on me.
> >
> > Thanks Gregg.
> >
> > Cheers, Gene Heskett
>
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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] need advice, idea shoppingIOW.

[andy pugh]

On Sun, 19 Jul 2020 at 16:54, Martin Dobbins  wrote:

> Are you going to share it with the world, so we can perhaps dispense with the 
> shenanigans with triangles and grumpy slicers?

It outputs SVG for a DLP, so isn't particularly useful here.
And it is a VB Macro for Inventor, so I doubt anyone here can use it.
The point I was making is that the only way to get curves is to start
with the native CAD geometry, not an STL.

But parts of it have been here for a while:
https://github.com/andypugh/SVG_Slicer

-- 
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] need advice, idea shoppingIOW.

[Martin Dobbins]

>If you want rounder curves, you need to decrease the triangle size in
>the input STL file.

>I only know of one slicer that outputs curves, and I wrote it :-)
>(And it works directly off the CAD model in Inventor, where curves do exist)

Are you going to share it with the world, so we can perhaps dispense with the 
shenanigans with triangles and grumpy slicers?

Martin



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Re: [Emc-users] need advice, idea shoppingIOW.

[andy pugh]

On Sun, 19 Jul 2020 at 11:20, Gene Heskett  wrote:

> And I have come to the conclusion that both cura and merlin that run the
> enders need to be replaced as neither has a G2 or G3 for circles

STL is a set of triangular facets. There are no curves for the slicer
to make G2 or G3 arcs out of.

If you want rounder curves, you need to decrease the triangle size in
the input STL file.

I only know of one slicer that outputs curves, and I wrote it :-)
(And it works directly off the CAD model in Inventor, where curves do exist)

-- 
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] need advice, idea shoppingIOW.

[Thomas J Powderly]

Gene

do you want to convert a series of short lines that approximate arcs

into g02/g03, to save space?

Or, described as 'fitting x y  pairs to a circle'?


Dave E was looking for similar ( a good while back) and I didnt find any.


If you have slices that can be processed in scripts with librecad (lua)

or esdxf(python)


I imagine some batch processing, layer by layer, slogging thru your 
megafile )



For python fitting a list of coords to circle there is

https://scipy-cookbook.readthedocs.io/items/Least_Squares_Circle.html


There a classic solution by Coopes but all the papers and code I've 
found are pay for.


( I hate those 'services; that charge for such information )


theres this implementation in Javascript


https://jsxgraph.uni-bayreuth.de/wiki/index.php/Least-squares_circle_fitting


but to get the demo to render i had to wander around the site till i 
found something that did render ,


then returm :-(

once it renders, refresh the page for a new random set of points

and a new fitted circle

tomp


On 7/19/20 5:19 PM, Gene Heskett wrote:

On Saturday 18 July 2020 22:21:20 Gregg Eshelman via Emc-users wrote:


Circa 1990: Have you heard of the new Hubble Cocktail? It's very
expensive, comes in a hand polished glass, and after you finish it,
your vision is all blurry.


ROTFLMAO!  I missed that one at the time, shame on me.

Thanks Gregg.

Cheers, Gene Heskett



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Re: [Emc-users] need advice, idea shoppingIOW.

[Gene Heskett]

On Saturday 18 July 2020 22:21:20 Gregg Eshelman via Emc-users wrote:

> Circa 1990: Have you heard of the new Hubble Cocktail? It's very
> expensive, comes in a hand polished glass, and after you finish it,
> your vision is all blurry.
>
ROTFLMAO!  I missed that one at the time, shame on me.

Thanks Gregg.

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] need advice, idea shoppingIOW.

[Gene Heskett]

On Saturday 18 July 2020 22:18:33 Gregg Eshelman via Emc-users wrote:

> PLA should have enough flex for the part of a cycloidal drive that has
> to flex. It also is pretty tough so wear would be a minimal issue.

If its tall enough to flex. This PLA seems to be pretty fragile cold.

And "cycloidal" hasn't a flex member, its the harmonic's that flex the 
gear.  And there are "harmonic" designs that use a wider belt turned 
wrong side out. If I could find the files to print one of those, it 
would already be tried.  But I see all these on u-tube but no place to 
grab the files. I may have to figure out how to reverse openscad to make 
internal gears. The parametric design tool works well but outputs 
sprockets too small by a fraction of a percent. I keep expanding the xy 
scales on the printer by .05% increments looking for the right size but 
haven't got there yet.  Bore sizes are too small too. To get 16.85mm's, 
I have to ask for 17.

And I have come to the conclusion that both cura and merlin that run the 
enders need to be replaced as neither has a G2 or G3 for circles, so the 
only belt teeth that reproduce well are the XL sized which can be 
reproduced as a series of straight lines but actually have a circular 
gullet when rendered in PLA if inspected with a strong glass. The 
semi-circular gullet stuffs do not render well at the scales involved. 
But so far, I have not been made aware of a slicer that uses g2/g3. 
There are 32 bit retrofit boards for the Enders, but can they do g2/g3? 
IDK.  If they can, I'll get one of them ordered Monday.

> Just don't run it fast and/or under a bunch of pressure without some
> lube. I suspect a silicone grease made for plastics (like that sticky
> white stuff often found in gear drives in cheaper power tools) would
> work for PLA.

Got a brand name?  I've gotten some lubriplate BB grade lookalikes but 
its not exactly the same stuff.
 
> If the part works well for a while then breaks, print another one.
> Print a spare to start with to ensure the one you use lasts a long
> time. ;)

Murphy's law in reverse, print 3, the first will last forever. But when 
you do need the spares, they've vanished. :-\

[...]

Cheers, Stay safe and well, 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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