Study On The Gap Control System Of The Electrical Discharge Machining In Gas

The advantages of the electrical discharge machining in gas are small tool electrode wear, high material removal rate, high machining accuracy, low pollution and so on, so EDM in gas has the higher practical value. However, the experiment research indicates: the discharge gap length using gas is smaller than conventional EDM using normal medium. It requires that the function of the gap control system is much higher. Therefore, this paper has done the research work on a new gap control system with high frequency response to the change status of the discharge gap.The paper has designed the gap control system of the electrical discharge machining in gas, which is based on the piezoelectric ceramics and it includes both of hardware and software. The hardware system includes a sample-and-hold circuit, a sequential control circuit, the comparison circuit of voltage, the circuit of analog-to-digital, single chip micro computer, the circuit of digital-to-analog, a power source of piezoelectric ceramics, the piezoelectric ceramics and so on. The paper analyzed that how they go to work and made the detailed explanation of the chip used in thesis.In the meanwhile, the paper also analyzed the method to write the assembly program for the gap control system and then has designed the programming for the circuit board basing on the ISA bus.The experiment result shows that the gap control system of the electrical discharge machining in gas can find out the best discharge gap according to the gap voltage and maintain machining until the machining is over. It can come up to the expectations.