Welding parameters in ultrasonic welding have a crucial influence on the strength of the welded joint. As part of the final assignment, we performed an ultrasonic welding process on samples of polysulfone reinforced with 30 % glass fibers at different joint coverages (1mm, 2mm and 3 mm) and at welding depths (0,2 mm, 0,35 mm, 0,5 mm). A uniaxial tensile test was performed on the base material in the transverse and longitudinal orientations. The tensile strength of the base material in the transverse direction was 61 MPa and in the longitudinal direction 119 MPa. For the welded samples, we found from the results that the tensile strength increases with the increase of the overlap and depth of welding. The biggest influence on the tensile strength has the overlap of the joint, and its increase is also more energy and cost-effective. Samples in which the fracture occurs in the base material and not the weld joint have higher tensile strength. This is achieved with an overlap of 2 mm or more, but the fracture occurs right next to the weld joint, because the material there is weakened due to the heat-affected zone. This also results in none of the samples reaching the tensile strength of the base material. The maximum strength of the joint with the lowest possible energy consumption is achieved with a joint overlap of 2 mm and a welding depth of 0,35 mm.
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