It is not your motor tuning, you are experiencing backlash (even though you tried to adjust for it.
Goto Ball Screws if you can.
with acmes (that come with the shoptask), you can try and adjust out your backlash with the nuts on the end of the axis, (ecept the Z, there you can set your spring pull back pressure higher).
To get a true reading on your axis with acmes.. lets say you want to measure from 0 to -1.... start about at +0.25", then move to 0, then move to x-1, measure here... THEN continue to move in same direction to x-1.25, THEN reverse direction back to x-1, again measure you position, are you at x-1, if not not the amount, then step jog your axis to your dros reading x-1. Then go back to X0 note the the two distances of the original x0 to x-1, and the x-1 to x0 (the x-1 here may have to been adjusted).
But in any case the amount you get in the range of x0 to x-1 back to x0 will be the range that you want to tune your moters in.... any slop outside of that range (your backlash axis change of direction moves x0.25 and x-1.25 will show you the back lash amount of the mechanics of your axis. (NOTE: a few trouble spots to watch for on the shoptask, the little pulleys on the servos (or steppers), have tiny set screws that often allow them to slip a little on the shaft. I recommend redrilling a large hole and putting a big set screw in. (also on the X axis at the direction change lever watch that your bushing are all the way secure, the screw might move alittle here along its axis. The Y table watch the bushings on the turn handle end.
scott  |