Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: callcbm on December 29, 2015, 02:02:39 PM
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I have stepper drives with belt drive reduced 4-1 . when drive take off start the same but seem to fight each other one going faster then the other then changing sides. you can watch it do it. Belts are tight pullys are the same size as well as the motors. Changed cables no difference. has to be in a setting in mach. Motor tuned the same.
Thanks Randy
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Are you 100% certain both motors are tuned exactly the same - speed, acceleration and steps per???
If yes it sounds like one side is losing steps.
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Yes tried different setting thought was loosing steps. didn't change . Change up down every setting I could think of save each made sure there identical .Thans Randy
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Are both drives programmed exactly the same on the dip-switches, assuming they have them??
Are both motors identical?
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both motors are identical and using g540 no dip switch
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Then failing it being a mechanical issue, to rule that out pull the motors of and make sure the axis slides freely on its own, i cant really offer much more up here, hopefully someone will chime in.
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What is the construction of the machine and is it square with all drive removed?
If drive tension is required to pull the machine into square the issue could be mechanical bind which will tend to alternate from side to side.
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FIRST question what controller are you using ?? LPT version or other ??
(;-) TP
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G540 with lpt
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The drive seam to race each other for the lead. I have a x axis setup that works fine just the slaved y . each side fight for the lead. The gantry was Squared when started but each motor is pulling it out of square but will change from side to side . Flipping the cables had no effect
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I would post your XML and someone can look to see if there are problems there. The problem sounds vaguely familar.
(;-) TP
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Are you sure your power supply is adequate ?
Russ
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Are you 100% sure BOTH motors are actually turning under power?
I had a similar issue when building and the gantry was being pulled along by one side which would then cause the other side to spring forwards every few inches, sort of like how you explain it.
I would pull both motors and set them side by side on top of the table, fit a marker - tape or pointer etc to each one and run some sync tests.
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found the problem was the shafts in the reduction pulley would turn almost a full turn then catch and then release. Know the opposite side is doing it. I dislike to have to use set screws to secure to a shaft as this would happen. And yes I did flatten were the set screw hit the shaft. First time setting pulse for movement right on the nose.
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It sounds like mechanical oscillation