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HEADING OF SMALL BI-METALLIC COMPONENTS FOR ELECTRIC CONTACTS

WOJCIECH PRESZ, ROBERT CACKO

Abstract: Electrical connectors mostly have silver contacts joined to the supplying and discharging electric current elements by riveting. In order to reduce costs, the rivet core of the contact can be replaced with a cheaper material such as copper. There is a wide range of commercially offered bi-metallic, silver-copper rivets available for the production of contacts. This generates a new situation in the riveting process, as the bi-metallic rivet is to be formed. In the analyzed example it is a small-sized object that places it near the limits of micro-forming. The riveting process was originally designed by classical upsetting. It was based on the results of FEM simulation taking into account the deformation of three materials included in the joint: two materials for rivet and sheet material. The FEM results were verified by the results of experimental studies indicating high compliance. The elimination method of the elastic deformations of the load system impact on the process forces was elaborated and it was used for comparative analysis with the force run obtained from FEM. The model simulating the working conditions of the connector was developed. Based on the joint load modeling results, the cause of possible delamination of constituent materials was determined. It was also defined the desired silver distribution in the connector head to eliminate the risk of separation of both materials during exploitation.

Key words: metal forming, heading, bi-metallic component