Study on discharge state detection of micro-EDM based on wavelet transform method

Micro electrical discharge machining (micro-EDM) is considered as one of the most effective methods for micro manufacturing. However, in micro-EDM, since the discharge energy is small and the discharge space is narrow, it is difficult to evacuate the discharge-generated debris from the discharge gap, which causes the frequent occurrence of short circuit and arc discharge resulting in low machining efficiency. To realize high efficiency and stability in micro-EDM, precise discharge state detection is necessary. In this paper, wavelet transform method was used to detect the discharge state under the transistor type pulse generator to achieve real-time detection with high accuracy. The discharge state detection method based on wavelet transform was theoretically analyzed and was realized with the field programmable gate array (FPGA) due to its high computation speed. Experimental investigations in micro-EDM were conducted, and the effectiveness of the discharge state detection method based on wavelet transform was verified.