Research On Bidrectional Narrow Pulse Generator Of Non-Resistance For WEDM

As an important part of WEDM (Wire Cut Electrical Discharge Machining) machine, pulse generator is one of main factors which influence WEDM process. WEDM is a method of erode metal using the heat caused by high frequency electrical energy. The single discharge pulse energy of the electrical pulse that inflicted is one of the key factors which influence surface coarseness that machined, So to get single discharge pulse energy, using pulse power of little pulse width is main approach to minish surface coarseness of the workpiece machined. After analyzing the using ratio of the electric energy of pulse generator on the WEDM machine in existence, it shows that only 20% of the electric energy is actually used discharge machining in WEDM, while the other 80% of the electric energy is wasted on the limiting resistance. Therefore, it has profound meaning to study on narrow pulse generator of non-resistance for WEDM.The recent research on the pulse generator in oversea and domestic are generally analyzed, basing on the reading to the related Chinese and foreign literature. Aiming at the low efficiency and bad surface coarseness of the pulse generator for the WEDM machine, a new type of pulse generator for WEDM is designed.The new generator comprises main circuit,main oscillating circuit,assimilating circuit,and driving circuit. It has none limiting resistances in the main circuit, canceling all dissipative elements. The using ratio of the electric energy has greatly raised by canceling the limiting resistances. In the design of the main oscillating circuit, the main oscillating circuit output the high frequency pulse voltage shape of the needing machining by the way of the single chip computer control writing, the peripheral equipment control reading and the programmable timing counter IC of 8254 control the pulse deferent cycle, which provides the precise adjustment on the pulse width and interval in a wide range. The least machining pulse width can reach 1 microsecond.Using the prototype of the pulse generator, the machining process experiments are carried out on the WEDM machine and the machining status is analyzed. The effect of energy-saving can be obviously observed. It can save 16% more electric energy than the traditional pulse generator when cutting the same area. The machining result is nice. The cutting speed is raised, accompanying the highly-used electric energy and the low wearing of the electrode wires. The machining function is preferably finished and the feasibility of the pulse generator is confirmed.