Abstract: A surface treatment method and apparatus therefor for providing wear and corrosion resistance, which includes relatively rotating a modified metallic member to be surface modified and a block, which may be metal only or may include a modifying material (e.g., ceramic or W-C/Co), and generating electrical discharge between the block and the modified metallic member to form a modification layer on the surface of said modified metallic member. If the modifying material is not in the block, it can be supplied via a dielectric bath or spray at the discharge interface. In this manner, the cutting edges of a cutting tool with a complicated shape can be surface modified easily to carry out tool surface treatment which increases a cutting tool life greatly. Cutting and surface treatment can be performed alternately as determined by a controller.

Abstract: An improved electric discharge machine with a numerical control unit includes an electrode configuration sensor in a machining vessel for detecting the configuration of a machining electrode before an electric discharge machining operation is conducted. According to one aspect of the invention, the electric discharge machining operation is performed while electrical discharge machining conditions are being automatically selected so as to permit the most suitable machining conditions for the electric discharge machining operation to be carried out with respect to the electrode whose configuration has been detected. According to another aspect of the invention, troublesome operations for setting the electrical conditions corresponding to the electrical discharge machining operation are eliminated.