Research of the Plastic Status Parameter and Instantaneous Clearance of APunching without Burr

摘要

The article mainly talks about the characteristic of common and fine punching and the quality ofrnshearing edge. Although the common punching has been widely applied, the quality of shearing edge is very poor.rnThe fine punching work-piece is better in quality. But it isn't still been widely applied, because the structure of diernis complicated and the manufacture of die and using pressure machine are expensive. A new fine punchingrnprocessing without burr is put forward by discussing the plastic status and press stress status of the material whichrninfluence the quality of the punching work-piece in the deformation zone, It provides the plastic status of materialrnto determine the parameter in the new processing and presents the maximum value of plastic deformation specificrnenergy when the material reaches the plastic status. The author has analyzed the initializing clearance andrninstantaneous clearance of the ordinary punching. The instantaneous clearance of the ordinary punching process isrninstable. By studying the author brings forward a kind of punching process which initializing clearance andrninstantaneous clearance are stable, that is the negative clearance fine punching process. Because of using thernnegative clearance fine punching process, the material of sheared distorting section comes into the plastic state.rnThe surface quality of the punching sheared edge is advanced 1.5 times than that of the ordinary punching. Thernrecommended value of depth of the negative clearance punching has been given in this article.