This paper describes a new method of die surface modification by ordinary Electrical Discharge Machining (EDM) tool.
First, the principle of this method is studied. Secondly, the reason for appearance of cracks on the surface of coating
layer in the electrical discharge coating with conventional pulse power supply are analyzed. At last, the new type special
pulse power supply with additional pulse current is designed. Scenix single-chip is selected as pulse generator, which
runs the fastest among all single-chips. The corresponding program can make the pulse power supply produce the
additional pulse current. At the same time, the special pulse power supply can communicate different machining
parameters with industrial personal computer by serial port of PIC single-chip according to the coating requires, and then
PIC single-chip convey machining parameters to Scenix single-chip by the communication interface. Through process
experiment, the special pulse power supply for electrical discharge coating behaves well, and the compacted coating
layer without cracks deposited on the surface of die by EDM can be obtained, which can prolong the life of die.