The Study Of Combined Intelligent Pulse Power Supply For Electric Discharge Machining

With the development of society and manufacture level,the traditional way to machine has failed to meet the requirement.Therefore,Electric discharge machining(EDM)is needed to remove materials that are usually hard to machine and always in complicated shape.It is widely used in many fields such as aerospace industry,motor industry and medical apparatus.Electric discharge machining(EDM)is a non-touched machining approach which use the thermal energy derived from electric sparks to remove the material.EDM has good performance in processing the micro-holes of metal materials whose cavity is complex.This paper has designed a new intelligent pulse power supply for EDM.Having analyzed the research papers of both domestic and abroad,the disadvantages of pulse power supply is that traditional pulse power supply rarely have intelligent surveillance.Based on this problem,this paper presents intelligent EDM surveillance strategy,and then designs the structure of intelligent pulse power supply for EDM.It includes hardware and software.Hardware is divided into different modules:DC power supply module,main circuit module,main microprocessor module,power amplification and drive circuit module,display module,data-collecting module,communicating module and power module.Software includes PWM program,display and key program,serial port communicating program,SPI communicating program,EDM gap status surveillance strategy.The main circuit use two MOSFETs to control the process of charging and discharging in capacitor.The two opposite PWM signals which come from the main chip STM32 are boosted by power amplification and drive circuit module to control the switch time of the two MOSFETs.The OLED screen is adopted to show the frequency and duty cycle value,four keys are installed to change the value.The task of communicating module is to transfer the data which is obtained by mainprocessor STM32 to computer to control the process of machining by using serial port which is transformed through USB-TTL transform micro chip.Power module provides 12 V,5 V,3.3 V voltage for the whole system.Data-collecting module acquire the gap voltage of EDM and then send to AD module to complete the analog-to-digit conversion,the digital data acquired transfer to main microprocessor STM32 to monitor the gap status.Fuzzy-neuro control system gather the information to help the main chip to handle the data which is a most effective way to achieve intelligent control.The voltage of new intelligent pulse power supply can be adjustable in 0-200 V,frequency in 0-10 KHz and duty cycle are also changeable.The pulse wave of the intelligent pulse power supply which is measured by oscilloscope is good for EDM.Compared the removal rate of intelligent pulse power supply with another one without intelligence,the result shows that the intelligent one has boosted the removal rate dramtically.