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Re: Position Errors Only on Diagonal Moves
« Reply #20 on: January 14, 2015, 05:21:55 PM »
Have you tried it with a G4P1 at the end of each move?
Can you monitor the encoder position in the servo drive software? (not sure what drives you have)

Hood

Hood,

I am afraid I am not all that familiar with the G4P1 command. Can you explain what it does?

I am not sure on monitoring the servo drives. I know that they are MaxSine drives. Beyond that I am not sure. Ray will probably know better than I will. The mill is a Novakon Torus Pro.

Nate

Offline Hood

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Re: Position Errors Only on Diagonal Moves
« Reply #21 on: January 14, 2015, 05:31:52 PM »
G4P1 will just pause the code for 1 second.
I am wondering if it is a tuning issue and that 1 second delay may show it up, ie it will give the drive plenty of time to get to position.
Hood
Re: Position Errors Only on Diagonal Moves
« Reply #22 on: January 14, 2015, 05:37:31 PM »
G4P1 will just pause the code for 1 second.
I am wondering if it is a tuning issue and that 1 second delay may show it up, ie it will give the drive plenty of time to get to position.
Hood

That makes sense. I will try it.
Re: Position Errors Only on Diagonal Moves
« Reply #23 on: January 14, 2015, 05:41:07 PM »
Hey folks, sorry ... I somehow missed those earlier posts. I'd retract mine if possible to keep the clutter down.
Jeesh, I'll try to pay better attention in the future. ::)
Again, apologies.  :-[
Russ  :P

 :)
Re: Position Errors Only on Diagonal Moves
« Reply #24 on: January 14, 2015, 05:48:13 PM »
Hey folks, sorry ... I somehow missed those earlier posts. I'd retract mine if possible to keep the clutter down.
Jeesh, I'll try to pay better attention in the future. ::)
Again, apologies.  :-[
Russ  :P

 :)

No need to apologize. I appreciate all the responses and input I can get. That said, I had set up some indicators and measured not only against the table but against the fixture plate to rule out the possibility of the x and y not being square.
Re: Position Errors Only on Diagonal Moves
« Reply #25 on: January 14, 2015, 08:16:42 PM »
Ray said this was a bed mill. Is it a commercial metal cutting mill ? Or more of a hobby level type ?
 
Just curious.
Russ

It's a Novakon Torus Pro - Perhaps not quite "commercial" level, but a big, strong machine - 25" X 15"Y 12"Z travels 1.5HP, 6000 RPM.  It's no wimp.  Same machine I use to run produfction parts for my PDBs and ATCs, and will do close to 4 cu. in/min. MRR on 6061 all day long without breaking a sweat, while giving better than +/-0.001" tolerance.

Regards,
Ray L.
Regards,
Ray L.

Offline BR549

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Re: Position Errors Only on Diagonal Moves
« Reply #26 on: January 14, 2015, 09:00:50 PM »
OK using a different PC from a KNOWN working machine and it did the same thing where as on the other machine it worked correctly ? That would rule out MAch3 and the PC would it not ??

IS this a servo drive machine ?? Have the servos been TUNED to the machine correctly ?? (;-) NOT just by ear but with a scope.  Put a medium load on the bed and tune it with a scope.

Try switching the 2 drives XY with each other and see IF the offsetting changes with it.  

Check the servo power supply voltages while running the code that offsets ?

You said that it is NOT a problem with following error ?? HOW did you check it. WILL the servo actually FAULT if you lock  down the servo motor and try to move it ?

(;-) TP



« Last Edit: January 14, 2015, 09:02:57 PM by BR549 »
Position Errors Only on Diagonal Moves
« Reply #27 on: January 15, 2015, 09:36:23 AM »
I got to run 2 more tests this morning:

Test 1
   - cut a 2" square that is 45 degrees from XY followed by a 2" square that is parallel to XY
  - use foam to eliminate any possibility of load resistance
  - use 15 ipm instead of 50.
  - run this on a different part of the table

GCode:

     G54

  (Toolchange Start)
     G53 G00 Z0.0000
         X[#100] Y[#101]
     G49
  M05
  M09
  (Tool #6, Aluminum - Pocketing - 1/4in Carbide Endmill)
  (TOOL/MILL,0.2500,0.0000,1.2500)
  M06 T6
     G43 H6
  (USR, Load Tool #6, Aluminum - Pocketing - 1/4in Carbide Endmill)
  M00
  (USR, 2D Contour1, Instance 1)
  M03 S6000
  (Toolchange End)


  M09
     G17
     G90 G00 X2.3510 Y1.3990
     G43 Z0.6000 H6
         Z0.2000
     (LEAD IN)
     G01 Z0.0394 F15
     (PLUNGE)
         Z-0.1000 F15.
     (CUTTING)
         X2.9521 Y2.0000 F15
         X1.7500 Y3.2021
         X0.5479 Y2.0000
         X1.7500 Y0.7979
         X2.3510 Y1.3990
     (TRANSITION)
     G02 X2.3731 Y1.4034 Z-0.1000 I0.0144 J-0.0144
     G03 X2.3952 Y1.4078 Z-0.1000 I0.0077 J0.0188
     (FINISH CUT)
     G01 X2.9874 Y2.0000
         X1.7500 Y3.2374
         X0.5126 Y2.0000
         X1.7500 Y0.7626
         X2.3952 Y1.4078
         X2.9874 Y2.0000
         X1.7500 Y3.2374
         X0.5126 Y2.0000
         X1.7500 Y0.7626
         X2.3952 Y1.4078
     (RAPID)
     G00 Z0.2000
         X5.3500 Y2.0000
     (LEAD IN)
     G01 Z0.0394
     (PLUNGE)
         Z-0.1000 F15.
     (CUTTING)
         Y2.8500 F15
         X3.6500
         Y1.1500
         X5.3500
         Y2.0000
     (TRANSITION)
     G02 X5.3625 Y2.0187 Z-0.1000 I0.0203 J0.0000
     G03 X5.3750 Y2.0375 Z-0.1000 I-0.0078 J0.0187
     (FINISH CUT)
     G01 Y2.8750
         X3.6250
         Y1.1250
         X5.3750
         Y2.0375
         Y2.8750
         X3.6250
         Y1.1250
         X5.3750
         Y2.0375
     (RAPID)
     G00 Z0.6000

  M09 M05
     G53 G00 Z0.0000
         X[#102] Y[#103]
     G49 G54 G90
  (USR, Program Done)
  M30

Results:



As you can see, the 45 degree square is still about + or - 0.042" off on one side. The square parallel to XY came out perfect.

Test 2
   - cut a 1.5" square that is 45 degrees from XY followed by a 1.5" square that is parallel to XY
  - use foam to eliminate any possibility of load resistance
  - use 15 ipm instead of 50.
  - run this on a different part of the table that previous tests.
  - cut the square backwards from my Normal tests

GCode:

     G54

  (Toolchange Start)
     G53 G00 Z0.0000
         X[#100] Y[#101]
     G49
  M05
  M09
  (Tool #6, Aluminum - Pocketing - 1/4in Carbide Endmill)
  (TOOL/MILL,0.2500,0.0000,1.2500)
  M06 T6
     G43 H6
  (USR, Load Tool #6, Aluminum - Pocketing - 1/4in Carbide Endmill)
  M00
  (USR, 2D Contour1, Instance 1)
  M03 S6000
  (Toolchange End)


  M09
     G17
     G90 G00 X2.1743 Y2.4243
     G43 Z0.6000 H6
         Z0.2000
     (LEAD IN)
     G01 Z0.0394 F15
     (PLUNGE)
         Z-0.1000 F15.
     (CUTTING)
         X2.5985 Y2.0000 F15
         X1.7500 Y1.1515
         X0.9015 Y2.0000
         X1.7500 Y2.8485
         X2.1743 Y2.4243
     (TRANSITION)
     G03 X2.1964 Y2.4198 Z-0.1000 I0.0144 J0.0144
     G02 X2.2185 Y2.4154 Z-0.1000 I0.0077 J-0.0188
     (FINISH CUT)
     G01 X2.6339 Y2.0000
         X1.7500 Y1.1161
         X0.8661 Y2.0000
         X1.7500 Y2.8839
         X2.6339 Y2.0000
         X1.7500 Y1.1161
         X0.8661 Y2.0000
         X1.7500 Y2.8839
         X2.2185 Y2.4154
     (RAPID)
     G00 Z0.2000
         X5.1000 Y2.0000
     (LEAD IN)
     G01 Z0.0394
     (PLUNGE)
         Z-0.1000 F15.
     (CUTTING)
         Y1.4000 F15
         X3.9000
         Y2.6000
         X5.1000
         Y2.0000
     (TRANSITION)
     G03 X5.1125 Y1.9812 Z-0.1000 I0.0203 J0.0000
     G02 X5.1250 Y1.9625 Z-0.1000 I-0.0078 J-0.0187
     (FINISH CUT)
     G01 Y1.3750
         X3.8750
         Y2.6250
         X5.1250
         Y1.3750
         X3.8750
         Y2.6250
         X5.1250
         Y1.9625
     (RAPID)
     G00 Z0.6000

  M09 M05
     G53 G00 Z0.0000
         X[#102] Y[#103]
     G49 G54 G90
  (USR, Program Done)
  M30

Results:



As you can see, the 45 degree square is still about + or - 0.042" off on one side. The square parallel to XY came out perfect.

Next tests:

- Flip XY servos around and see if the error flips around.
- run the 2" test and put a G4P1 after every move to test for servo tuning


Nate
Fine Line Automation
www.finelineautomation.com
Position Errors Only on Diagonal Moves
« Reply #28 on: January 15, 2015, 09:46:31 AM »
OK using a different PC from a KNOWN working machine and it did the same thing where as on the other machine it worked correctly ? That would rule out MAch3 and the PC would it not ??

One would think. I am not entirely sure though. The thing that is preventing me from saying absolutely yes it is not Mach 3 or the pc is the fact that the squares parallel to XY are coming out perfect and I am not losing steps running the program.

IS this a servo drive machine ?? Have the servos been TUNED to the machine correctly ?? (;-) NOT just by ear but with a scope.  Put a medium load on the bed and tune it with a scope.

This is a servo drive machine. I am assuming the set is were tuned at the factory. I have not done any tuning and I don't have a scope to check it out.

Try switching the 2 drives XY with each other and see IF the offsetting changes with it. 

Check the servo power supply voltages while running the code that offsets ?

Swapping the drives is my next test.

I will need to get with Ray to figure out which lines I need to measure voltage from.

You said that it is NOT a problem with following error ?? HOW did you check it. WILL the servo actually FAULT if you lock  down the servo motor and try to move it ?

(;-) TP

What error are you referring to? If I run the table up to the hardstop the servo drive definitely faults.

Regards,

Nate


Nate
Fine Line Automation
www.finelineautomation.com

Offline Tweakie.CNC

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Re: Position Errors Only on Diagonal Moves
« Reply #29 on: January 15, 2015, 11:02:45 AM »
Running your Gcode, using a laser, the centreline of the toolpath produces a 1.2" square on the first pass and a 1.25" square on the second pass. Both the X-Y aligned square and the 45 deg. square are absolutely identical in dimension - there is no error.

So I think I can safely say there is absolutely nothing wrong with your Gcode or the Mach3 interpretation of that Gcode.

Hope this helps in finding your problem.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.