Electroconductive ceramic tooling for dry deep drawing

摘要

Large use and waste of lubricating oil has become a very serious environmental issue. Hence, oil-free metal forming is one of the most promising solutions to this issue. Among them, ceramic tooling is proposed because of its good tribological properties. Its feasibility for dry deep drawing has been studied in laboratory; ceramic tooling is thought to be applicable to dry deep drawing. However, the workability of ceramics in tooling preparation is inferior to that of alloy tool steel. In the present paper, electroconductive ceramics are proposed as an alternative tool material. The electroconductive ceramic tooling is shaped by electric discharge machining such as wire electric discharge machining, die sinking electric discharge, and so forth; any shape of tools can be easily accommodated by these methods. The workability of electroconductive ceramics by electric discharge machining as well as the deep drawability with electroconductive ceramics tooling is experimentally evaluated. Selection of electric conditions for electric discharge machining influences the surface finish quality of electroconductive ceramics. Zirconia-based electroconductive ceramic die has an equivalent deep drawability in dry to conventional SKD11 die with lubricant.