The effect of technological parameters of PMMA thermoplastic welding in the hot air stream on the quality of joints

Abstract

The work covers the welding of thermoplastic polymethyl methacrylate (PMMA) and concerns the assessment of the impact of the main welding parameters on joint strength. The strength test of welded joints made of thermoplastic material was carried out. The aim of the study was to determine the influence of the main technological parameters of welding, such as: temperature and welding speed, gas stream output, filler rod pressure, diameter and type of hot air gun nozzle on the strength of the obtained joint. The method of sample preparation and testing was performed in accordance with the guidelines of PN-EN 12814-2: 2002 "Tests of welded joints in semi-finished products made of thermoplastics ‒ Part 2: Tensile test". Visual evaluation of welded samples and analysis of results obtained from the tensile test made it possible to draw conclusions about the influence of selected welding parameters on joint strength. The decisive influence on the strength of joints was caused by welding defects, in the form of lack of side wall fusion and porosity.