Effects of different heating strategies on the joint properties during infrared welding of glass fiber reinforced polyamide 6

In infrared welding, the heating phase is the phase offering the highest flexibility of choice regarding the process parameters. In this phase, the process parameters such as the heating time, emitter power, and emitter-component distance can be individually selected and combined with each other. The defined heating phases have a different influence on the joining components. In this work, the effects of four heating strategies and their influence on the resulting temperature distribution over the joining surface, the possible thermal material degradation, the morphology of the joining zone, and the short-term tensile strength of the welded samples are investigated. In order to investigate the morphology, microsections are prepared which enable transmitted light microscopy of the black PA6 GF50 used. In summary, it can be concluded that different heating strategies have a different influence on the material even if the generated melt layer thickness is kept the same. Three of the four strategies result in material degradation on the joining surface. However, this has almost no effect on the resulting short-term strength of the weld. The results allow the interpretation that a high joining pressure compensates for the influence of the material damage by pressing the damaged material into the bead.