position error in multiple axes
We've been wrestling with a difficult problem for several months, The X and Y axes (and possibly the Z) are losing position. We can see this when the machine jogs home after a partfile, it comes home to a slightly different location than it left. Over time, this error increases from a few thousandths, to -3/16" in the x and +1/8" in the Y
We have spent a fair amount of time with Tom and Dave troubleshooting this issue (whose help I've truly appreciated), but we're stuck.
PRS 48x96 (2007/8 version) standard.
-The dust collector is off.
-The spindle can be on or off, unplugged or not.
-Vacuum on or off.
-We have used 3 computers to replicate the problem, with everything from windows xp to the most recent update of 10.
- We have used the recommended settings from SB.
-The USB cable is short, doesn't run parallel with power cables (and we've installed a new one).
-We switched power supply circuits from one leg to another, from one panel to another. Used an isolation transformer on the power circuit. Both the computer and Drive box are on the same circuit.
- The pinions are tight to the tracks and do not appear worn.
- The symptoms are worse doing parts with lots of curves, simply cutting rectangles with the shopbot controller doesn't seem to have a perceptible problem.
- the problem occurs air cutting and cutting materials.
I can't think of a logical place that noise would interfere with the communication cables or stepper cables that we haven't looked at.
The attached image shows the resulting error after an hour of running the part file.
Thanks for looking at this, I hope that somebody has had this happen and worked through it and can share the solution.
Ben Thoron
The Old Globe
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