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General Mach Discussion / Re: First Post - Help with setup issue?
« on: June 08, 2009, 03:23:03 AM »
I will agree that behaps the backlash could be seamlessly integrated into the move, I don't know how it "senses" the changes that may be needed, nor do I understand if the number of "pulses" for a given line are calculated all at once, or whatever, to allow the requisite "backlash pulses" to be tacked on.
However it is done, if you have backlash, the axis will appear to stop moving, until the necessary number of pulses to reverse the gear train have gone through the motor.
The only other thing that comes to mind is that, where two axis are moving together, either diagonally or in an arc, one axis (usually the one with less distance to move) takes it's pulses at a slower rate to keep the line (or arc) true. In this case, backlash MUST be applied first otherwise the movement of one axis relevant to the other(s) will not be accurate .
My machine is a combined lathe and mill, a medium sized Warco, and although new(ish) it suffered badly from backlash. I think I have that contained now, and I can turn out accurate stull. The next problem is 140 steel railway wheels to re-turn to a better profile (My CNC man did them wrong)
However it is done, if you have backlash, the axis will appear to stop moving, until the necessary number of pulses to reverse the gear train have gone through the motor.
The only other thing that comes to mind is that, where two axis are moving together, either diagonally or in an arc, one axis (usually the one with less distance to move) takes it's pulses at a slower rate to keep the line (or arc) true. In this case, backlash MUST be applied first otherwise the movement of one axis relevant to the other(s) will not be accurate .
My machine is a combined lathe and mill, a medium sized Warco, and although new(ish) it suffered badly from backlash. I think I have that contained now, and I can turn out accurate stull. The next problem is 140 steel railway wheels to re-turn to a better profile (My CNC man did them wrong)