Analysis of the Weld Quality of Plasma Arc Welds: A Case Study of Conductor Welds in an Electrical Stator

Abstract

Plasma arc welding (PAW) is a technique used in the electrical component industry for joining electrical conductors in devices such as motors and alternators. With the limited number of theoretical methods and simulation tools to predict the metal flow characteristics and its interaction with the process parameters during the welding process, weld design must still rely on the designers experience and the trial and error method. As a consequence, the process parameters and the weld quality may not be as originally expected at the design process. Based on the fact that a good quality of the final product has to be guaranteed, the analysis of the PAW process and the resulting weld quality is presented in this paper. The aim of the work was to obtain a clear perspective on the influence of various process parameters on the weld quality. In order to measure the influence on quality, first “quality” was defined. Secondly, there were various options to measure the quality, some of them being destructive, others being non-destructive. The development of the measurement methods was then proposed based on electrical tests, mechanical tests and visual inspection of the welds. Finally, using these methods and the experimental data obtained from the actual welding process, a new approach to evaluate the weld quality was proposed and is presented in this paper. The results reveal that the electrical impedance, the mechanical strength and the geometry (visual measure) of the weld are related and can be used to estimate the weld quality.