Application of electromagnetic forming in terminal crimping using different types of field shapers

Abstract

Mechanical crimping is the most used method of pressure connection for permanent electrical contact in electrical and electronic equipment. Terminal plastic deformation on multi-wire strands is carried out to achieve mechanical strength and electrical conductivity. Electromagnetic (EM) is assumed to be an alternative method to overcome the challenges of spring back in the terminal on tool relaxation, cracks, non-uniform deformation, reduced strength, decreased the durability of joints in conventional crimping tool. Implementation of the field shaper (FS) has been proposed to enhance the magnetic field to concentrate the magnetic pressure at the required location for the effective terminal crimping over the wire strands. In this work, crimping was carried out using FS as a tool. Experiments were carried out utilizing tapered FS, single step FS and double step FS on aluminum terminal over seven strands aluminum wire strands that are commercially utilized for making interconnections. Results like contact length, contact resistance, terminal deformation, surface hardness, cross-section hardness and pull-out tests were found out and compared simultaneously. Also, the test results were compared with the samples crimped using a conventional crimping tool. From the results single step FS was found to be the most efficient FS than double step FS whereas the tapered FS was the least efficient. The results will be helpful in determining the geometry for the field shapers in similar applications.