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Author Topic: HELP: Mach 3 losing its reference position on Y axis...  (Read 3822 times)

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Offline Chet

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HELP: Mach 3 losing its reference position on Y axis...
« on: September 18, 2016, 01:36:58 PM »
I've been using Mach 3 for many years with excellent results.
But recently the program is failing and I cannot figure out why:
1) My programs appear to  run normally, but at a random point the Y-axis will shift and then keep using the shifted point as it's new location.  For example, if a cut is supposed to end at 10", it will shift up roughly .25" and shift the whole pattern up .25" and continue to cut with the .25" error.
2) The program code continues to show the correct numbers, but the program is referencing a different number.
3) I've also noticed that the first cut on the X-axis also involves a Y-axis shift, but settles down after the first line of code.
Attempts at a remedy include:
1. Using a new copy of my CNC program (I learned early on to make multiple copies) but that does not solve the problem.
2. Using a different cutting program, but the problem still occurs.
3. Added a power line backup unit (UPS) to catch any power line glitches, but that did not solve it.
Your suggestions are welcomed!
I was considering replacing the Y-axis motor, but the randomness of the problem "seems" to preclude that.
And, if you're wondering, I am running Mach 3 on a dedicated XP computer.
Re: HELP: Mach 3 losing its reference position on Y axis...
« Reply #1 on: September 18, 2016, 04:02:40 PM »
sounds like slack on the Nema coupler? though going up in dimensions doesn't fit right...

try some air cuts

Offline RICH

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Re: HELP: Mach 3 losing its reference position on Y axis...
« Reply #2 on: September 18, 2016, 05:12:47 PM »
I need some info from you before commenting.

Post your xml file that you are using.
Are you using steppers?
Post the gcode for a file that causes the a random shift of the axis.

For now,
RICH

Offline Chet

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Re: HELP: Mach 3 losing its reference position on Y axis...
« Reply #3 on: September 18, 2016, 07:26:22 PM »
Hi Rich!
Thank you for your interest in helping to solve my problem.
Please find attached my Mach 3 XML file, my program .txt file and a photo showing the problem.
(The pen in the photo is showing the start of the problem...  I stopped the program shortly after, but it would have continued at the new distance.)
My motors are 305 oz steppers with 8 wire output, with two sets combined causing 6 wires to
Code: [Select]
go to the driver board (White, Brown, Orange + Brown, Blue + Yellow, Black, Red)
Chet
( 4 Holmes Oval )
( Remember to set H1=roughing, H2=finishing )
( Roughing: Flat End Mill 0.25 )
( Finish: Flat End Mill 0.063 )
G20 G40 G80 G90
T01 G49 G43 H01
F20 S400
M03 M08
G00 Z 0.0
G00 X0.001 Y0.001
X0.0843 Y0.251 Z 0.0
X0.1677 Y0.251 Z -0.1875
X3.3343 Y0.251 Z -0.1875
X3.4177 Y0.251 Z 0.0
G00 Z 0.0
X6.8343 Y0.251 Z 0.0
X6.9177 Y0.251 Z -0.1875
X10.0843 Y0.251 Z -0.1875
X10.1677 Y0.251 Z 0.0
G00 Z 0.0
X10.1657 Y0.376 Z 0.0
X10.0823 Y0.376 Z -0.1875
X7.249 Y0.376 Z -0.1875
X7.1657 Y0.376 Z 0.0
G00 Z 0.0
X3.0823 Y0.376 Z 0.0
X2.999 Y0.376 Z -0.1875
X0.1657 Y0.376 Z -0.1875
X0.0823 Y0.376 Z 0.0
G00 Z 0.0
X0.0843 Y0.501 Z 0.0
X0.1677 Y0.501 Z -0.1875
X2.751 Y0.501 Z -0.1875
X2.8343 Y0.501 Z 0.0
G00 Z 0.0
X7.4177 Y0.501 Z 0.0
X7.501 Y0.501 Z -0.1875
X10.0843 Y0.501 Z -0.1875
X10.1677 Y0.501 Z 0.0
G00 Z 0.0
X10.1657 Y0.626 Z 0.0
X10.0823 Y0.626 Z -0.1875
X7.749 Y0.626 Z -0.1875
X7.6657 Y0.626 Z 0.0
G00 Z 0.0
X2.5823 Y0.626 Z 0.0
X2.499 Y0.626 Z -0.1875
X0.1657 Y0.626 Z -0.1875
X0.0823 Y0.626 Z 0.0
G00 Z 0.0
X0.0843 Y0.751 Z 0.0
X0.1677 Y0.751 Z -0.1875
X2.3343 Y0.751 Z -0.1875
X2.4177 Y0.751 Z 0.0
G00 Z 0.0
X7.8343 Y0.751 Z 0.0
X7.9177 Y0.751 Z -0.1875
X10.0843 Y0.751 Z -0.1875
X10.1677 Y0.751 Z 0.0
G00 Z 0.0
X10.1657 Y0.876 Z 0.0
X10.0823 Y0.876 Z -0.1875
X8.1657 Y0.876 Z -0.1875
X8.0823 Y0.876 Z 0.0
G00 Z 0.0
X6.999 Y0.876 Z 0.0
X6.9157 Y0.876 Z -0.1875
X6.749 Y0.876 Z -0.1875
X6.6657 Y0.876 Z 0.0
G00 Z 0.0
X3.5823 Y0.876 Z 0.0
X3.499 Y0.876 Z -0.1875
X3.3323 Y0.876 Z -0.1875
X3.249 Y0.876 Z 0.0
G00 Z 0.0
X2.249 Y0.876 Z 0.0
X2.1657 Y0.876 Z -0.1875
X0.1657 Y0.876 Z -0.1875
X0.0823 Y0.876 Z 0.0
G00 Z 0.0
X0.0843 Y1.001 Z 0.0
X0.1677 Y1.001 Z -0.1875
X2.001 Y1.001 Z -0.1875
X2.0843 Y1.001 Z 0.0
G00 Z 0.0
X3.001 Y1.001 Z 0.0
X3.0843 Y1.001 Z -0.1875
X3.5843 Y1.001 Z -0.1875
X3.6677 Y1.001 Z 0.0
G00 Z 0.0
X6.6677 Y1.001 Z 0.0
X6.751 Y1.001 Z -0.1875
X7.1677 Y1.001 Z -0.1875
X7.251 Y1.001 Z 0.0
G00 Z 0.0
X8.251 Y1.001 Z 0.0
X8.3343 Y1.001 Z -0.1875
X10.0843 Y1.001 Z -0.1875
X10.1677 Y1.001 Z 0.0
G00 Z 0.0
X10.1657 Y1.126 Z 0.0
X10.0823 Y1.126 Z -0.1875
X8.4157 Y1.126 Z -0.1875
X8.3323 Y1.126 Z 0.0
G00 Z 0.0
X7.499 Y1.126 Z 0.0
X7.4157 Y1.126 Z -0.1875
X6.6657 Y1.126 Z -0.1875
X6.5823 Y1.126 Z 0.0
G00 Z 0.0
X3.6657 Y1.126 Z 0.0
X3.5823 Y1.126 Z -0.1875
X2.8323 Y1.126 Z -0.1875
X2.749 Y1.126 Z 0.0
G00 Z 0.0
X1.9157 Y1.126 Z 0.0
X1.8323 Y1.126 Z -0.1875
X0.1657 Y1.126 Z -0.1875
X0.0823 Y1.126 Z 0.0
G00 Z 0.0
X0.0843 Y1.251 Z 0.0
X0.1677 Y1.251 Z -0.1875
X1.6677 Y1.251 Z -0.1875
X1.751 Y1.251 Z 0.0
G00 Z 0.0
X2.5843 Y1.251 Z 0.0
X2.6677 Y1.251 Z -0.1875
X3.501 Y1.251 Z -0.1875
X3.5843 Y1.251 Z 0.0
G00 Z 0.0
X6.5843 Y1.251 Z 0.0
X6.6677 Y1.251 Z -0.1875
X7.5843 Y1.251 Z -0.1875
X7.6677 Y1.251 Z 0.0
G00 Z 0.0
X8.501 Y1.251 Z 0.0
X8.5843 Y1.251 Z -0.1875
- code removed to shorten length -
X10.1885 Y10.2093 Z -0.1875
X10.1885 Y10.2302 Z 0.0
G00 Z 0.0
G00 Z.99
G00 X0 Y0
M30
 %

Offline RICH

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Re: HELP: Mach 3 losing its reference position on Y axis...
« Reply #4 on: September 18, 2016, 09:39:47 PM »
Please post  the complete code file. Rename the file to chet.txt and post it.

Do you have a motor curve for the steppers?


RICH

Offline Chet

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Re: HELP: Mach 3 losing its reference position on Y axis...
« Reply #5 on: September 18, 2016, 09:58:06 PM »
Hi Rich!
I tried to post the complete code, but the website said that it exceeded the allowable number of characters.
The full code is 43,624 lines long with typically 4+ commands per line.
I am not sure how you want me to attach it.  Should I use the 'code' button and paste the full code between the code icons?
As to the motor curve for the steppers, I could use a sniping tool and grab the motor tuning curves if that is what you are referring to....
I apologize for not providing you the info you need....
Please advise....

Offline RICH

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Re: HELP: Mach 3 losing its reference position on Y axis...
« Reply #6 on: September 19, 2016, 07:25:37 AM »
Chet,

Post the code as a "file",  as long as the file size is below allowable of 6000 KB
it should post.

Provide a link to the exact motors you have and I will look them up.

Provide a link to the drives you are using.

Assume this is a home built router machine, if so a picture tells me lot,
if not, post a link to the exact machine.


Sorry about  dragging this out but your problem is random ( been there so i know
what a PITA it can be ) and there are lots of things that can be the culprit.
Yes I have thoughts, but, would rather look at the big picture, and be constructive
in replies.
  
-------------------------

What version of Mach3 are you using?

What software are you using to generate the code?


What are you drive amp settings and power supply voltage and
total amp rating at that voltage?

Are the motors getting hot such that you can't hold your hand on them after
running say a 1/2 hour?

Is the following correct when running the program?

The router table has 3/8-12 Acme threaded rods and nuts for the X & Y axes,
imperial mode, and has switches wired in series.
Code is run at 20 ipm, for over 5 hours while cutting styrofoam.
A shop vac and the router is on when running the program.


The xml file used shows the following axis tunning:
axis steps per vel  accel  zero  
X    9600      38    12
Y    9600      38    11
Z    9600      38    8


Please do not change any settings and start screwing around.
My intent here is to test based on some starting point to find the problem.

Till then,
RICH
« Last Edit: September 19, 2016, 07:31:23 AM by RICH »

Offline Chet

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Re: HELP: Mach 3 losing its reference position on Y axis...
« Reply #7 on: September 19, 2016, 10:09:02 AM »
Hi Rich!
OK, I think I have all of my ducks in a row here....
My motors and control board came from Hobby CNC:
http://hobbycnc.com/product/hobbycnc-pro-combo-kits/
Here's more info on the motors:
http://hobbycnc.com/product/305-stepper-motor/
My kit, which includes a power supply, is no longer offered.
Here's info on the unit I have:
3 Axis Unipolar Chopper Control.
Accepts 5, 6, or 8 wire stepper motors.
42 VDC maximum input voltage, 12 VDC minimum input voltage
3.0 Amps Max per phase, 500 ma minimum.
Idle Current Reduction to 50% when idle for 10 seconds.
On board voltage regulation for 5-volt logic with 24 VDC cooling far from motor power supply.
My version of Mach 3 is:  Mach3 2.0, ver R3.042.029
My code generator is Acme Profiler - Coyote Edition
www.gunstar1.com/scispec/scispec.htm
(The Acme program generates a G92 code which has to be erased before using!  You solved the problem this causes for me years ago!)
The motors have felt pretty darn warm, but after a 1/2 hour test this morning I got the following:
X motor: 120 F,  Y motor: 106 F,  Z motor: 100 F  (perhaps a bit cooler than usual)
Table uses 3/8-12 Acme with switches in series
Code is run at 20 ipm for over 5 hours
A shop vac also runs with a router while running the program
The xml files are correct as of now:  X 9600s/38v/12a  -  Y 9600s/38v/11a -  9600s/38v/8a
You can see my unit running if you go to www.ancrsundials.com and click the video box in the lower left corner of the home page
I tried to insert my program, but it was rejected as too long.
I'll see if I can send it in several pieces....
Thank your perseverance in helping me resolve this issue.
The problem is intermittent - the 4th attempt on the above cut came out perfect!
Chet

Offline Chet

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Re: HELP: Mach 3 losing its reference position on Y axis...
« Reply #8 on: September 19, 2016, 10:16:34 AM »
Hi Rich!
This file is going to be problematic....
The complete file has 914,301 characters and spaces.
If I broke it up into 20,000 character chunks, it would take 45 chunks....
That does not seem desirable....
I have an email on my website if you prefer an alternate response.
Chet

Offline Chet

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Re: HELP: Mach 3 losing its reference position on Y axis...
« Reply #9 on: September 20, 2016, 04:40:38 PM »
I BELIEVE I HAVE A SOLUTION!
First, thank you to everyone who offered their insights and suggestions.
And a special Thank You to Rich who offered many valuable insights into diagnosing the problem.
Because the problem was intermittent, I felt those who suggested it might be a motor slipping problem might be on to something.
I went back to my motor tuning set up and did some minor tweaking:
I changed my velocity from 38.124 to 37, and my acceleration from 10.937 to 7.0
I'd rather run a bit slower with reliability.
Finished my first 5-1/2 hour cut with the new settings and all went well!
-0- On a side note, some time back I did have problems with random Limit Switch triggering.
Turns out the cause of the problem was that I'd used solid wire to correct the micro switches.
One of those wires had broken due to the constant flexing.
I replaced the solid wire with stranded, and all has been OK since.
Once again, thank you to all who read my post and offered their possible solutions.
Chet