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Max Velocity and Acceleration - or how not to beat your ballscrews to death?

slow-poke

Ultra Member
My past CNC conversions used stepper motors so were inherently slow.

My latest conversion (8x30 Knee mill) with DFU2005 and DFU1605 ballscrews uses 750W ac servos, These are a world different in terms of torque at speed and I can move the table near silently (compared to steppers) and fast, test run at 100IPM is no problem.

I would imagine the forces at the ballscrews are not trivial. So my question is if I want longevity what are good limits to place on acceleration and velocity?
 
I would imagine you only need to worry about acceleration. What are the specs for the motors? That's where I would start.
 
I would imagine you only need to worry about acceleration. What are the specs for the motors? That's where I would start.
The motors are quite potent 7.2/2.39Nm, with a really wide torque curve so they can easily move the 8x30 table at > 100IPM and land within a couple of tenths.

I don't have any experience with ballscrew longevity when operating at 20x max human capability;-)
 

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I would bet that somewhere in either the software running the show, or in the drivers themselves, there is the ability to select a maximum acceleration rate, or it may be tied in with setting the maximum current limits to be considered acceptable to the control.
 
I'm still running the ACME screws at 150 IPM max. That is a scary fast speed and this fall I hope to start converting to ball screws. I'm not to worried about exceeding ball screw speeds.
 
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