Electrical Discharge Machining (EDM), as a high-precision and advanced process technology, fundamentally relies on utilizing the electro-erosion phenomenon generated by spark discharges to progressively remove material from the workpiece, thereby achieving the desired shape. This process involves not only the conversion of electrical energy into thermal energy but also a series of complex physical and chemical reactions. A deep understanding of its basic principles is crucial for mastering EDM technology, improving machining efficiency, and enhancing product quality.
During the EDM process, voltage is applied between the workpiece and the tool electrode. High-frequency pulsed discharges generate sparks. These sparks produce localized high temperatures, causing material to be eroded from the workpiece. As the tool electrode continuously feeds forward, the workpiece is gradually eroded, ultimately achieving the predetermined shape. Mastering the principle of electrical-to-thermal energy conversion is essential, as is understanding the complexity of the physical and chemical reactions involved.
In EDM, the workpiece and tool electrode are connected to a pulse power source, forming a discharge circuit. An automatic feed control system ensures a constant small gap is maintained between the tool and workpiece. This allows the pulsed voltage to break down the dielectric medium between the two poles, initiating spark discharge. The intense heat generated by this discharge instantaneously erodes metal from the surfaces of both the tool and the workpiece, creating tiny craters. As pulsed discharges continue consecutively, the tool electrode progressively feeds towards the workpiece. Ultimately, the inverse shape of the tool is replicated onto the workpiece, completing the machining of the required part. The entire machined surface consists of numerous such microscopic craters arranged in an orderly fashion, collectively forming the desired complex shapes and textures.