Improving the pulse utilization rate in EDM machining using the FPGA module

Abstract

In Electrical Discharge Machining (EDM), maintaining an appropriate discharge gap distance is crucial. Failure to compensate the electrode in time and excessive feeding can result in arc burn, short circuits, and incomplete dielectric breakdown due to insufficient electric field strength. Therefore, it is essential to enhance the accuracy and reliability of the servo control system. This paper utilizes the LabVIEW (Field-Programmable Gate Array) FPGA module for servo control implementation. The acquired gap voltage signal, processed through a low-pass filter, is fed into the FPGA control system for comparison with the preset threshold voltage. It should be noted that the voltage threshold value varies depending on the discharge conditions, which is calculated by simulating the different machining waveforms. Consequently, the servo feed control based on the gap voltage includes three cases: tool moving forward, tool stationary, and tool moving backward. This tool-feeding strategy significantly improves the pulse utilization rate and machining performance.