Design of Cold Heading Process of a Screw for Storage Parts

Abstract

Fasteners are used to join the various electronic products and machines. So, the quality and reliability of the fastener are strongly requested. In this study, the analyses of the multi-stage cold forging of TORX screws for storage parts are carried out. In manufacturing of TORX screws, crack and folding defects are observed. Therefore, the analysis is focused on the prediction of the defects. Based on the analysis results, the upper die and process conditions are redesigned to reduce the defects. The upper die shape for preform forming is redesigned to prevent folding and sharp shape change. The Cockroft-Latham damage criterion is introduced to predict the crack initiation. Analysis results shows that the maximum Cockroft-Latham damage value is decreased by 40% in the forming using the modified upper die.

Fastener Product Cold Heading Process Formulation and Precision Die Design

“…Fastener products are a major category of hardware products [1][2][3]. Wenzhou Longwan is the largest fastener base in the country, with an annual consumption of several billion yuan.…”