Research On Micro-edm Pulse Generator And Strategy Of Servo Controling

With the development of Micro/Nano Science and Technology, countries all over the world have been paying high attention to Micro-Machining, which features with small shape and size or operations under super-small scale. As one of the important part of Micro-Machining, Micro-EDM has an important application value in the field of aerospace, precision instruments, medical equipment, textile printing and automotive industries.Based on the analysis of discharge and breakdown characteristics of Micro-EDM generator and transistor pulse generator, the PWM technology was employed to get the voltage adjustable from 0 to 120V and a multi-functional micro-EDM generator collected RC, controled RC, transistor and high frequency grouping discharge modules that can achieve high-frequency and tiny power discharge was also developed exploiting the principle that a series of variable sequential logic pulse producted the controller whose core are PIC microcontroller and Complex Programmable Logic Device (CPLD) driver high-speed switching devices. The advantages of many detection methods, like average gap voltage, average Pulse-Width detection and the average digital Pulse-Width detection, are combined together to propose a transistor flexible pulse voltage detection strategy characterized by a simple circuit structure, without affecting the duty cycle reset, good pulse voltage following performance during discharging. The sofeware system of Micro-EDM with online seting parameter and real time feedback fuction is constructed with the PC interface control program of Visual C++, PIC microcontroller's serial communication program, Scenix microcontroller's A/D converter results high-speed sampling and statistical analysis program, and CPLD's program of high-frequency pulse generator. Many experiments showed detecting error of traditional average gap voltage detection method is 16 times that of transistor flexible pulse voltage detection strategy, which fully indicated that the new Pulse-Width voltage detection method has good pulse voltage following performance. It was observed that the RC-generator can produce lower energy discharge and processing gap smaller by experiments to machining micro axis and micro holes using the multi functioned Micro-EDM generator. Therefore, RC-type micro-EDM generator could be more suitable for micro-structures, where accuracy and surface finish are of prime importance.