Stick-slip mechanism study of CNC heavy-duty horizontal lathe feed systems based on dynamics

When CNC heavy-duty horizontal lathe feed systems is running at a low velocity, the stick-slip phenomenon will be introduced. The stick-slip phenomenon will seriously affect the working accuracy, work piece surface roughness and position accuracy. In this paper, structural characteristic of the feed system of CNC heavy-duty horizontal lathe is analyzed and gear rotor systems dynamics is applied to study the stick-slip mechanism of the feed systems. Elastic dynamics model of the feed systems which considers translatory degrees of freedom and rotational degrees of freedom is set up, at the same time, the influence of the time-varying stiffness excitation, deviation excitation and damping on the dynamics system is also considered. Elastic dynamics response of the feed systems excited by time-varying mesh stiffness and external load has been computed using the Newmark numerical method. Then, the carriage of the feed system displacement was simulated by LMS Virtual.Lab Motion Software as a contrast to the result of the dynamic response solved by numerical method. On this base, measure of avoiding the crawl phenomenon will be suggested.