Laser microwelding of small diameter wire to a contact Available to Purchase

This work is an attempt to evaluate feasibility of the laser welding process of small diameter wire to a contact. In particular, the paper addresses characterization of laser spot welded 32 AWG solid copper/silver plated wires to contacts on 0.050 in. centers. The copper alloy contacts were provided on strips in two lots, one unplated, and the other with 75 μin. of plated Nickel. An industrial type IR, Nd:YAG, pulsed laser was used to produce welds, in order to simulate manufacturing environment. Metallurgical analysis, SEM, and nanoindentation characterization have been used in setting up the welding process and in final evaluation. Quality of welds was also evaluated by a tensile test and the results are presented in a statistical format. The test results indicate that the tensile strength of the laser welded wire, relative to the bare (unwelded) wire, yielded 95.47% for joints on unplated contacts, and 98.25% for Nickel plated contacts. Microscope examination of samples, after pull test, shows that all wires broke behind the weld area. These results significantly exceed the required minimum tensile of a welded joint, which is 60% of the tensile strength of a bare wire. They also indicate that laser welding of small diameter wires to high density contacts can be considered as a valuable process alternative.