edm die sinking reproduces, in a metallic workpiece, the shape of a tool called electrode. injection molds for plastic parts are very frequently machined by die sinking. the shape given to the electrode is that of the obj......edm die sinking reproduces, in a metallic workpiece, the shape of a tool called electrode. injection molds for plastic parts are very frequently machined by die sinking. the shape given to the electrode is that of the object that is going to be molded. in the machining area, each discharge creates a crater in the workpiece (material removal) and an impact on the tool (wear of the tool/electrode). there is never any mechanical contact between the electrode and workpiece. the electrode is usually made of copper or graphite.