machine tool velocity saturation


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Can anybody tell me exactly where the saturation of the velocity for a machine tool axis feed drive is reached? Or is it really ever reached while machining?

The velocity can be programmed while generating the trajectories and the limit velocity is not accepted from this phase…So the saturation elements are implemented “just in case” ? Further, the limits can really be reached while machining?

I need to know what really happens on real machine tool, a vertical 3 axis milling center eventually. Anything: links, docs, can be helpful.

Whatever 3-axis machine you have, the servo motor will NEVER, EVER reach speed saturation (torque saturation is a different story), unless it is in runaway and I doubt that it would reach it then unless the runaway axis was a mile long, otherwise it's going to hit the overtravel limit switch and disengage the drive. The other extreme case (which I have never seen or heard of) is the axis drive assembly (pinion or ball screw) broke away from the servo motor itself and then went into runaway to boot! The parameters are for safety because if it can happen then it might so safeguards must be implemented. That parameter(s) will be compared with the servo motor data and when the CNC calculates realtime feedrate, the realtime feedrate will be compared to the max allowable feedrate (converted or non-converted) and if exceeded then error. Hopes this helps.