A large quantity of lubricant waste has become a very serious environmental issue. For the zero emission of lubricants, dry deep drawing is efficient; however, it is generally very difficult to apply it to metal sheets. As one of the most promising methods, the use of ceramic tools is proposed because of their high tribological properties. However, the workability of the ceramic tools is poor. Therefore, the forming of a complex shape is difficult and even the forming of a simple shape is expensive. Thus, the use of electroconductive ceramic tools in this research is proposed. The electroconductive ceramic tools can be formed by electrical discharge machining methods (e.g., wire and die milling electric discharge machining methods). Therefore, the shape of a metal mold can easily be molded. Using an electroconductive ceramic as a plastic forming tool, a high drawability was confirmed and dry deep drawing of 10,000 times was achieved. The surface roughness of a dry deep drawing cup was as large as that of a non-dry (oil) deep drawing cup.
Two types of electroconductive cer~amic tools are employed in this study to describe the dry deep drawing behavior of cold rolled steel sheets into cylindrical and rectangular cups. Each of electroconductive ceramic tools is machined by die sinking electric discharge. Four experimental setups are also pr-epared to investigate the effect of the surface roughness on the quality of dry deep drawing: the unlapped and the lapped electroconductive cer~amic dies in dry condition and the unlubricated and the lubricated SKDll die. Fven without lubricating oils, cylindrical and rectangular cups are successfully deep drawn over 10,000 by the present tooling. Fwthermore, compared to the lubricated SKDll tooling, surface r'oughness of deep drawn cups is reduced by the present ceramic tooling. Fine finishing in ceramic tooling never leads to low surface roughness in the deep drawn cups since the work materials make unconstr~airied plastic flow in the direction of thickness. Hence, the unlapped electroconductive ceramic tooling is favored for practical ceramic tooling to preserve well-defined contact interface between metallic work sheets and cer'amic tools in dry deep drawing. In addition, the rectangular cup drawing is evaluated by more severe conditions than the cylindrical cup drawing because the stress concentrates on the corner parts. Through this test, it is demonstrated that the electroconductive ceramic tooling has a potential of practical dry deep drawing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.