Research On Piezoelectric Self-adaptive Micro-EDM CNC And CAM System

Electrical discharge machining (EDM) is a kind of non-conventional machining method, which is becoming more and more popular in many fields. Piezoelectric self-adaptive micro-EDM is developed from micro-EDM, which makes use of the converse piezoelectric effect. In piezoelectric self-adaptive micro-EDM, the piezoelectric ceramic vibrates regularly during machining, and it pushes the workpiece to vibrate at the same time. The vibration of the workpiece could help prevent short circuit and arc discharging; it also improves the stability of micro-EDM. The piezoelectric self-adaptive micro-EDM CNC system and CAM system will be studied in this paper, and the CNC software and CAM software are developed. At last a series of experiments are conducted to verify the functions of the CNC and CAM system. The main work is as follows:The piezoelectric self-adaptive micro-EDM CNC system is studied. The theory and characteristics of piezoelectric self-adaptive micro-EDM is analyzed, and the functions of the CNC system are discussed. Then the hardware of the CNC system is designed based on the model machine. To develop the software of the CNC system, the decoding and interpolation algorithm of piezoelectric self-adaptive micro-EDM CNC technology are studied in this paper. The CNC software is developed with VC2010. This new kind of open CNC system has many advantages such as low cost, high precision and good flexibility.The CAM system of piezoelectric self-adaptive micro-EDM is studied. The functions of the CAM system is analyzed, To realize the generation of the CNC code of two dimensional structures, the radius compensation of tool electrode wear and the machining path planning are studied, then the two dimensional CAM software is developed with VC2010. To generate CNC code of three dimensional structures, the traditional milling function of UG CAM is analyzed; it is found that the3D CNC code of piezoelectric self-adaptive micro-EDM can be generated with UG CAM. An example of CNC code generating shows that the CAM software works well. The control algorithm of micro-hole and two-dimensional structure machining is studied. According to the characteristics of micro-hole machining, the control algorithm is designed, which is realized with speed controlling. The control algorithm of two dimensional structures machining based on static of discharge state is also designed, it can not only control the speed of tool electrode according to machining states, but also can compensate the tool electrode wear during machining. Extensive experiments show that the control algorithm is correct.The piezoelectric self-adaptive micro EDM based on laminar manufacture is studied. Inspired by the RPM technology, the machining of3D structure is transformed to the machining of2D structure by dividing the3D structure in to many thin pieces. To improve the machining quality and simple the control algorithm, uniform electrode wear piezoelectric self-adaptive micro EDM is studied. Then the machining path is planned to improve the machining quality by increasing the tool electrode tracks overlap rate and optimizing the tool electrode tracks. The method of fabricating long tool electrode with thin reverse copying block is also discussed. A series of experiment verifies the above work.