Research On The Machine Tool Of Electrical Discharge Milling Nonconductive Superabrasives

A new technique named Assisting Electrodes Electrical Discharge Milling for nonconductive superabrasives machining is proposed. It removes materials by spark channel energy of EDM and can mill all kinds of complicated surfaces of nonconductive superabrasives by using the cylinder electrodes. And it's a big achievement of EDM for nonconductive materials and will bring great influence to the application of nonconductive superabrasives.According to the theory of Electrical Discharge Milling nonconductive superabrasives by assisting electrode technique, the work condition of workbench is analyzed and its velocity characteristics, mechanics characteristics and positioning accuracy are ascertained. Except that the work parameters of workbench are computed and the feeding system is designed and also is simulated by Pro/E software.A temperature fields and thermal distortion mathematical model about the feeding process of ball screw system is established according to the special work condition of tools, and this model is simulated with finite element method considering the influence of groove on screw surface area and nut moving, so we get the rule of temperature distribution and the relations between screw deformation and temperature. The results provid a kind of theoretical reference for designing the cooled structure and compensating the feeding error due to thermal distortion of ball screw feeding system.According to the theory of Electrical Discharge Milling nonconductive superabrasives by assisting electrode technique, a special spindle which can vibrate and rotate with the electrode is designed. The vibration structure is carried out by electro-magnet and the structure rationality is analyzed according to electromagnetism. In addation, inner rushing structure and the leak proof structure are designed at joint. In order to adapt to different electrodes radius, a special electrode clamping structure is set which can also be sealed easily. The power supply and insulation system is also researched carefully. The whole system is simulated with Pro/E and a temperature field analysis is completed by ANSYS software. Milling cutter theoretical analysis and design are completed, and the cutter materials and manufacturing methods are choosed. Simple experiments are designed and NaOH solution is selected as conductive medium. According to these condition, the parameters which influence machining efficiency is analyzed and validated by drilling hole experiments. Milling groove experiments are carried out and the feasibility is proved that the machining of complicated surfaces of nonconductive superabrasives.