Study Of Ultrasonic Vibration Precision Cutting For Plastic Material

With the development of science and technology, because machining accuracy and surface quality of work piece are more strictly required, precision and ultra-precision technique is very important in the field of mechanical engineering, microelectronic engineering, biology engineering, especially in national defense industry. This technique impacts the accuracy of products and the accuracy impacts performance of it. It is a major approach to product high precision part adopting high precision machine. However, this approach is consumption on financing. Many technique problems must be solved before precision and ultra-precision machine are produced, which restricts its application seriously. Using existing equipment and adopting new-type multiple machining is a new approach to improve machining accuracy of precision machine. It is significant to break foreign technique blocking, improve the performance of advanced weapons, shorten technological gap distancing developed countries, and promote the development of national defense.Ultrasonic vibration cutting is a new-type non-traditional machining, a multiple machining. It can resolve precision machining problem effectively under certain condition. But research on cutting mechanism is not mature, study some processing affects from the test representation, mostly. Embedded elastic zone model of cutting zone is established in this paper. By means of solving the wave equation under a given initial condition and boundary condition, making force analysis of cutting zone, dynamic stress intensity factor is showed. Dynamic effect caused by ultrasonic vibration provides condition for leading fracture of work piece, so cutting force falls down.At the same time, an elastic-plastic finite element model of vibration cutting is put forward. Materials harden and strain ration correlation is considered in this model. Interacting between work piece and tool is analyzed by finite element method, and cutting zone stress is simulated. Stress variation of a point corresponding to tool tip is described. At last, SHPB impact test is made to proof above theory analysis results in a finite degree.A calculation model about relationship between average cutting force and vibration parameters is established by analyzing the relative movement between tool and work piece in ultrasonic vibration cutting. Using the method of simulation, an effect rule on cutting force is provided. It offers a theory gist for selection of vibration parameters in practical vibration cutting.Contact surface between tool and chip is abstracted into a friction pairs with ultrasonic vibration, and the real contacting surface is analyzed. From the viewpoint of coarse peak adhere, furrow and debris furrow, friction force is analyzed. Under the condition of ultrasonic vibration, the calculation model for the relation between coefficient of friction and surface roughness is presented. Finally an experimental device for measuring the kinetic coefficient of friction was design and test is performed.In this paper an ultrasonic vibration cutting test system is designed. Some experiments about surface roughness of work piece and vibration cutting forces are made using this test system. Perfect results are given by comparison between test and theory.