Research Of Micro-energy Controlled Pulse Power Supply For Micro Electrical Discharge Machining

Micro-EDM technology is a new processing method developed on the basis of traditional EDM technology.Due to its advantages of non-contact,high processing accuracy,micro energy controlled discharge energy.The micro-EDM processing technology has an irreplaceable position in special processing fields such as narrow,deep holes,and small holes.This paper designs a new type of micro-EDM pulse power supply.Compared with the traditional power supply,this power supply has a wider range of adjustable power pulse parameters,more accurate discharge gap detection,better electromagnetic compatibility,and a more stable system.Aiming at the problems of the traditional RC type EDM pulse power supply parameters such as small adjustable range and uncontrollable processing parameters,this paper develops a micro ESM pulsed power supply with adjustable frequency and duty ratio.The power supply is mainly composed of a signal generation module,a drive module,a power amplification module,and a gap control module.The main circuit module of the micro-EDM pulse power supply is the core component of the entire power supply.This article uses a signal generation circuit based on the DDS chip AD9851 as the core.In theory,a 0-1 MHz square wave signal output can be achieved on the AD9851 chip.At the same time,it programmed the signal generation procedure of the AD9851 and the implementation program for waveform adjustment.Design the PWM power regulation circuit.In this way,the pulse waveform with controllable frequency and duty ratio can be realized.Select N-channel enhancement type MOS transistor IRF6775 as power switching device,and the MOSFET dedicated driver chip UCC37321 is used to amplify the pulse waveform and control the turn-on and turn-off of the power switch tube MOSFET.Reasonable design of MOSFET peripheral circuits,used to achieve circuit isolation,fast drive and buffer filter functions.Finally,using the combination of voltage signal and current signal to detect gap discharge signal processing,and timely processing feedback information to drive the motor to make feed and retreat movement.In order to ensure the normal operation of pulse power during processing.Finally,debug the developed micro-EDM power supply.Test pulse waveform at 0-600KHz and 10%-80%duty cycle,the pulse waveform is stable,can requirements of micro-EDM processing.The EDM test was conducted to observe the ability to process micro-pits.Processing tests were performed under the same frequency with different duty cycles and the processing rules were observed.The micro-EDM power supply designed and researched in this paper has the characteristics of high discharge frequency,narrow pulse width,small discharge energy,good processing stability and adjustable parameters.Compared with the traditional EDM power supply,it is more suitable for the micro EDM that requires good surface quality and high machining accuracy.