Vibration modelling of machine tool structures

Productivity in modem machine tools is acheved by using high cutting velocities, spindle speeds and feed rates. A restriction for large material removal rates is the tendency of machines to chatter (structural vibration) for large depths of cut. This work is concerned with improving machine tool performance by understanding and ultimately controlling vibration in machine structures. If vibration due to chatter under load conditions can be controlled, then component surface finish can be improved and the life of components extended. The first step in this research is to measure and interpret vibration and model the structures, which are to be controlled. Appropriate sensors need to be selected and designed to measure self-excited vibrations. The vibrations of the investigated machines need to be understood by analysing the sensor signals and surface finish. Recent advances in micro-machining technology have resulted in a new type of accelerometer that is an order of magnitude lower in cost than traditional types. Results have shown that these sensors can be successfully used to replace their more expensive counterparts. This paper describes the first step into this research.