Ultrasonic Vibration Machining System And Rotary Ultrasonic Machining Processing Simulation

As the development of modern industrial and scientific experiments, industry products with high precision, high pressure and temperature resistance and small-scaled are more and more applied in various fields. Because the materials of these products such as carbide, stainless steel, engineering ceramics, optical glass and crystal are hard to be processed and coast too much, so the application of hard brittle are limited. does not depend on the conductivity of the material, and generates only a few heats, so thermal damage and micro-cracking is avoided. Therefore, Ultrasonic machining has uniquely advantages in hard brittle materials machining.Ultrasonic vibration system is mainly composed of ultrasonic transducer, ultrasonic horn and tool. It can convert the high-frequency oscillatory voltage into high frequency mechanical vibration to process the work piece.At present, the material removal mechanism of rotary ultrasonic vibrate machining (RUM) has not being a conclusion. Because vibrate frequency of the tool is too high (>16KHz), and the amplitude of the tool are too small that people can not directly observe the material removal process. Therefore, the finite element simulation method becomes an effective means to solve this problem.When using rotary ultrasonic machining processing a through-hole, there always being an edge chipping in the export. The reason is that tool directly contacts work piece, and when the remaining material in the hole is few, and coupled with the support position of work piece is near the bottom of the hole, there always be a big stress concentration around the edge of internal diameter. To predict the crack propagation direction and identify the factors that will affect the crack direction, this paper for the first time applies extended finite element method (XFEM) to rotary ultrasonic vibration machining in order to predict the crack propagation direction.The main contents of this paper are as follows,1、According to one-dimensional vibration theory of variable cross-section bar, the dimension of rotary ultrasonic vibration system is designed, and a set of calculation formula is summarized. Then the model of RUM system designed by the above mentioned dimension is model analyzed. The effects of resonant frequency caused by tool wear and tool diameter change are analyzed.2、Theoretical model of material removal include impact, abrasion and torn is focused. LS-DYNA finite element software is used to imitate the processing of RUM. The simulation follows the max principal stress fracture criterion. The surface stress distribution is get.3、This paper for the first time applies extended finite element method (XFEM) to rotary ultrasonic vibration machining in order to predict the crack propagation direction. Crack propagation of three-point bending test imitated and get the result coincide with the actual. Edge-chipping appeared in ultrasonic machining through-hole is simulated using XFEM, and get the crack direction coincide with the actual very well.4、According to the phenomenon of edge-chipping in RUM, an experiment is designed to investigate parameters to reduce edge-chipping.