Vibration of the ball screw drive

The ball screws used in the feed systems of the CNC machines work with continuously increasing cutting speed. When the speed of the balls reaches certain level, the repetitive shocks (impact forces) generated by the balls in the transient phase of the balls' motion increase the system vibrations. A relationship has been found between impact forces and design parameters of transient phase in function of rotational speed. Digital simulation of these forces for definite screw and ball diameters in function of rotational speed has been investigated. The frequency of impact forces should not be equal to the resonance frequency of driving system because it could result with a damage to a ball screw mechanism. A harmful phenomenon of a servo drive system resonance frequency has been examined. (C) 2012 Elsevier Ltd. All rights reserved.