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

[slow-poke]

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?

 

[Susquatch]

I would imagine you only need to worry about acceleration. What are the specs for the motors? That's where I would start.

 

[slow-poke]

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;-)

 

[trevj]

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.

 

[jcdammeyer]

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.