MANUFACTURE OF INSULATOR FOR SPARK PLUG, PRESS PIN USING IT, AND SPARK PLUG

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method of an insulator for a spark plug capable of easily pulling a press pin out of a molded body in molding of raw material powder. SOLUTION: When an insulator is molded in a rubber press, a hard carbon base mold release film 60 mainly comprising amorphous carbon is formed on the surface of a press pin 50. Releasing property of the press pin 50 from a molded body becomes excellent and the press pin 50 can smoothly be pulled out of the molded body without generating cracks or break. As a result, since lubricant coating to the press pin 50 can be eliminated or reduced, a molding process is simplified, and yield of molded bodies is enhanced.