Failure analysis of a cold-extrusion punch to enhance its quality and prolong its life

A cold-extrusion punch used to manufacture sockets undergoes severe impact loading and severe wear in the metal forming process. Failure in the cold-extrusion punch frequently occurs and is difficult to avoid. Owing to the complicated manufacturing process and the lack of service history of the cold-extrusion punch, detecting the major causes of the punch failure is difficult. Therefore, this study analyzes the major causes of the failure of a cold-extrusion punch by initially examining the mechanical properties of the cold-extrusion punch to identify defects in its related performance. Eliminating such defects is necessary to enhance the quality of the cold-extrusion punch. To determine the major causes of failure of the cold-extrusion punch, the characteristics of the failure are compared with those of well-known failure mechanisms, including the macro- and micro-characteristics of failure mechanisms. By closely examining the results of the mechanical properties and the results of the failure analysis of a cold-extrusion punch, this study proposes an effective method to avoid punch failure and prolong the punch life. (C) 2000 Elsevier Science S.A. All rights reserved.