Ultrasonic cutting as a nonlinear (vibro-impact) process

The machining process with the superimposing of ultrasonics is considered. The accumulated experimental results are explained theoretically in the framework of rheological models, It is confirmed that under the influence of high frequency vibration, the phenomenological transformation of elasto-plasticity into visco-plasticity and fluidization of dry friction occurs. The dynamic characteristics of transformed machining processes are obtained. They include the dependence of reduced cutting forces on the material and vibration parameters. It is shown that excitation of the vibro-impact mode of tool-workpiece interaction is the most effective way of using ultrasonic influence on dynamical characteristics of machining. The dynamics of an ultrasonic cutting machine under technological load is investigated. The nonlinear amplitude response of the vibrating tool in the process of cutting is obtained. The theoretical results are confirmed by experiments. The method of stabilization of resonant ultrasonic excitation is described. The advantages of ultrasonic cutting and possible ways of using it are discussed. (C) 1998 Elsevier Science B.V.