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Author Topic: Drifting Z dimension  (Read 1686 times)

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Drifting Z dimension
« on: August 22, 2015, 08:54:19 PM »
I am running version R 1.84.000 of Mach 3

I have a mechanical dial indicator on the Z axis and have a m1 pause programed near the start of my part program just after a Z0.0 line.  I religiously check the dial indicator on each pass to mechanically verify that Z is at zero.

On a number of occasions over a few months, I have found the dial to read minus, today minus .004 (this was after running about 15 parts without a problem).  Since I was cutting oversize on this pass, I completed the cut and found the part to in fact be -.004.  I made a .004 correction to the tool offset and and following parts were AOK.

I am sure that it is not a mechanical problem.

Any suggestions would be appreciated.

Thanks, Quin

Offline ger21

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Re: Drifting Z dimension
« Reply #1 on: August 22, 2015, 09:17:06 PM »
For starters, you're using a 9-1/2 year old version of Mach3. First thing I'd try is a newer version maybe?

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Offline Pugsly

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Re: Drifting Z dimension
« Reply #2 on: August 22, 2015, 09:29:32 PM »
I suspect that you are trying to drive the z-axis a bit too hard.  Have you tried adjusting the motor tuning down just a smidge?  Doesn't seem like you are off that much.
Re: Drifting Z dimension
« Reply #3 on: September 06, 2015, 08:04:42 AM »
Thanks for the idea.
Cutting back both the acceleration and the velocity slightly did the trick.

Any suggestions on a procedure or test program to set up motor tuning with a margin of safety?