Welding stability assessment in the GMAW-S process based on fuzzy logic by acoustic sensing from arc emissions

Purpose: The present research work has as purpose detecting perturbations, measuring and assessing the welding stability in GMAW process in short circuit mode named hereafter as GMAW-S process. Design/methodology/approach: Welding trials were performed with a set of optimal input welding parameters. During experiments were induced some perturbations on the welding trajectory. It causes alteration on the stability of welding resulting as consequence geometrical shape deformations. During each experiments, acoustic emission signal coming from electric arc as well as arc voltage and welding current were acquired aided by a card acquisition and virtual instrumentation software. A heuristic model was performed as knowledge base rules of a fuzzy logic system. This system has two inputs and one output. Some additional welding trials were performed for assessing its performance. Findings: It was performed a welding stability assessment system based on fuzzy logic. As well as, this system is based on non-contact sensing what reduces the loading effects on the welding process. Research limitations/implications: In the present work was monitored just the acoustic emissions coming from arc. Although that, the results were satisfactory, an approach on data fusion of sensors including electromagnetic emission sensors could improve the quality assessments system. Originality/value: The non-contact welding stability assessment methods have reduces loading effects and a heuristic approach on the relations between arc emissions and welding stability allows quantifying nonlinear variables such as knowledge and experience of skilled welders, such that, it is possible to represent linguistic terms numerically what could be used as an on-line monitoring system of welding processes.