I have a knee mill with a Centroid M400 control. I'm having an odd issue...I can do a rev/in adjustment and get the measurement perfect for any given distance, but the measurements will distort at different distances.
I'll explain.
I followed the directions in TSB 36 from the centroid website on a 3" gauge block. I then remeasured it and the distance measured was 3.0005". Sounds good.
So then I measure a 2" and 1" gauge block and the distances came out to 1.9986 and .9974 respectively.
So what's happening? If the Revs/in is good at 3", shouldn't it also be good at 1"?
I guess it could be missing a couple of thousandths every time it starts its movement, of maybe accidentally adding it, I don't know.
Yes, in theory if the pitch of the axis, revs/in, is set correctly the machine should go to the exact physical location no matter the distance that is commanded. Depending on how you are measuring the 2" and 1" block, the backlash of the axis might be the cause of your issue. Please also follow the attached tech bulletin to verify the backlash for the axis is correctly set. If you are still having issues with positioning, it could be due to a physical issue such as the encoder or the motor physically slipping on you. It could also be an issue with the ballscrew "drunkeness". The Centroid control can correct for that "drunkeness" with the ballscrew compensation table. You can manually create your own ballscrew compensation table following the attached tech bulletin.
Position Error
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