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Messages - cmnewcomer

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31
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: July 06, 2008, 08:23:46 PM »
Brett,

Yes, I have 0.004 baklash on the x and 0.003 on the y.  I've set it up to compensate and to not compensate and the results are the same.

My problem is that the error is cummulative.  If I do single axis x moves or single axis y moves I can do them all day long and everthing remains in sync.  If I do combined xy moves, I progessively get off by about 0.010 per cycle.  In other words, if I do G1X2Y2 followed by X0Y0, I will not be back at X0Y0.  I am about 0.010  off.  If I do the same cycle again, it's about 0.020 and so on a and so forth.

What's more puzzling is that I can do complex arc moves combined with complex xy moves and it stays right on?!

At this point I don't know wether to suspect the computer, the electronics, or my software configuration.  Just looking for ideas and do appreciate the suggestion.

Best Regards.

Carl

32
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: July 06, 2008, 03:39:45 PM »
Just completed some more testing and the Sherlin 1/2 Mode did not fix the problem.  I re-installed all of the software and went through the entire setup and tried both Sherlin and non Sherline mode and nothing seems to work.

I can perform single axis moves without any problem.  Always returns to starting point with no deviation using a dial indicator.  The Dial indicator also matches the DRO.

However, when I do simple xy axis moves combined, the deviation from the origin begins.

When I setup an oscilloscope, it was mostly square with some minor noise in the corners.  Not that I know much about what it should look like or how to describe it but that's the best I can do.  Does anyone have a picture or diagram of what it should look like?  Or some more information and how to interpret the output of the oscilloscope?

The thing I find most interesting is that I can do a complex milling operations milling out one quadrant of a gear spoke which reapeat 6 times just going deeper each time and it's spot on.  No deviation.  This makes no sense to me.  How can it do partial circles, complex xy moves, and other moves and still be right on for each of the 4 quadrant I'm milling?  It just seems to be simple xy move operations between the quadrants where the deviation is occurring.

I'm probably overlooking something obvious but I have not been able to fixure it out.  If anyone has suggestions, as always, it would be greatly appreciated.

Best Regards.

Carl

33
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: June 30, 2008, 08:59:04 PM »
Chip,

Yes.  I think for now I'm going to keep it in Sherline 1/2 Mode and do another run on a gear blank.  If everthing turns out OK, I may just leave it for now so I can get back to clock making.

I'll keep an eye on the forum and for new versions to see if someone finds a solution for saving the dir and step pulse.

The feedback and help from you and the others is greatly appreciated.  Thanks again.

Best Regards.

Carl

34
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: June 30, 2008, 08:01:38 PM »
Chip,

I have R2.63.  Yes, you are correct in that if you don't exit Mach 3 it won't persist the settings to the xml file.  Basically, if you set the values and don't go back into Motor Tuning (I did not test other scenarios), the values will be correct.

Best Regards.

Carl

35
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: June 30, 2008, 07:02:34 PM »
OK, this may or may not be of interest to the developers so please take it with a grain of salt.  The value appears to be persisting to the xml file.  Howeve, if you enter the motor tuning and exit, it decrements it.  To ensure this was happening, I did the following:

1. Enter Motor Tuning, set the  step pulse to 4 and the dir pulse to 4, save and exit Mach3.  Checked the xml file and settings were 4980 and 4980 respectively.
2. Enter Motor Tuning, change nothing but press Save and then exit Mach 3.  Checked the xml file and the settings were 3984 and 3984 respectively.
3. Enter Motor Tuning, change nothing but press Save and then exit Mach 3.  Checked the xml file and the settings were 2988 and 2988 respectively.
4. Enter Motor Tuning, change nothing but press Save and then exit Mach 3.  Checked the xml file and the settings were 1992 and 1992 respectively.
5. Enter Motor Tuning, change nothing but press Save and then exit Mach 3.  Checked the xml file and the settings were 996 and 996 respectively. 

This appears to be a programmatic bug when saving the settings.  For some reason it's decrementing each time.  Hope this helps.  Good news is were not crazy.

Best Regards.

Carl


36
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: June 30, 2008, 05:45:52 PM »
I have a 6" dial indicator that I setup to test the x and then the y travel and it was very accurate except for the backlash of the respective axis.  I then setup an edge finder for centering over a hole and tried the combined xy movements.  When returning to the hole and moving the z axis down, the edge finder was revealing approximately 42 thousands of error cummulate for each move.

I'm concerned about the Sherline mode so will try to get the settings in the xml.  It looks like each unit from the screen is saved as a multiple of 1995. 

I appreciate everyones recommendations.  Once again, it's been invaluable.

Best Regards.

Carl

By the way, I attached the g-code which is a plain text file.

37
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: June 29, 2008, 09:35:27 PM »
Thanks again for the replies. 

Yes, I've tried many combinations to get the value to save but no luck  It's odd, it saves on my Dell XP but not on my Dell Latitude 8100.  Unfortunately, I can't get the steppers to work on the XP at all so I tried my older Latitude which I was at least able do get things running on.

OK, the Sherlin 1/2 mode seems to work.  The tests I did with running the xy together and then going back to zero truly zero'd.  I'll do some more comprehensive testing this week but this is very promising.

Thanks very much.  This forum is invaluable for rookies like me.

Best Regards.

Carl

38
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: June 29, 2008, 08:35:13 PM »
Yes, I've tried to set it higher but it won't save.  I have a separate thread discussing this problem but have not found a solution.  I was looking at some of the xml files thinking I may be able to set it there but know that may not be a supported solution.

If you have some suggestions on how to get the new setting to persist, I would greatly appreciate it.

Best Regards.

39
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: June 29, 2008, 03:45:41 PM »
More information:

1. The voltage with G90F5X3 from zero is 54.4 contstant.
2. The voltage with G90F5X3Y3 from zero is 53.8 constant.
3. I have been unable to change the Step "Pulses" and even have tried what others have recommended in a separate post.  The Gecko feedback I got was to set it to 2 but it always remains at 1 no matter what I do to save the new setting.
4. I will try and see if I can set the DIR "Pulses".  Got this confused when I first read it.

My motor tuning configuration that finally seemed to produce reliable results is below.

Thanks again to everyone for the feedback.  I'm stumped and need fresh ideas to track this down.

Best Regards.


40
General Mach Discussion / Re: Progressive Move Error with X and Y
« on: June 29, 2008, 03:10:29 PM »
Thanks for the replies.  As for the setup, I have Nema 34 steppers on the x/y axis, Nema 23 stepper on y axis, gecko 201s, cnc4pc breakout board, 48v unregulated power supply, and Mach 3. 

I thought I already set it up properly and did many tests to ensure it moved 1 inch forward and 1 inch backward in both the x and y direction along with many other tests.  I ran testing circles 1, 2, 3, and 4 inches in diameter and it worked fine.   I then moved on to some test runs with aluminum to enure the program ran properly.  Everything seemed to checkout.

The gear I pictured was crossed out using the program I ran.  the interesting thing is that the it appeared to drift as it cut each quadrant but cut each quadrant properly!  At that point I did some more test as follows:

Test 1:
1. Zero all axis in Mach3.
2. G90X1.5Y1.5
3. X0Y0

I'm now off by 0.042 thousands.

Test 2 continuing from Test 1 above I did:

1. X1.5Y1.5
2. X0Y0

I'm now off about 0.084 thousands.

Test 3 starting over zeroing everything:

1. G90X1.5
2. X0
3. X1.5
4. X0

I could do the above as many times as I like and it was spot on when returning zero.

Test 4 starting from Test 3 above.

1. G90Y1.5
2. Y0
3. Y1.5
4 Y0

I could do the above as many times as I like and it was spot on returning to zero.

I then did all test in G91 mode and the results where the same when moving a single axis vs both at the same time.  Very confusing?!  How can movements with a single axis be spot on and movements with both axis at the same time produce drift?  I would have thought that the single axis moves and the circle tests confirmed that I setup the motors correctly in Mach3.  Maybe there's more to the setup than I realized but I can't find it.

Hood, I'll check the voltage and see if it's changing. I assume you mean at the supplyl output source correct?  These tests were all done at 10 ipm and it's a 48v unregulated power supply so hopefully it's not fluctuating at these speeds but it's somehting to check.  Thanks again for the feedback.

Best Regards.

Carl

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