Laser transmission joining of thermoplastic fasteners: Application for thermoset CFRP

A laser transmission-based joining process is investigated, joining one thermoplastic adherend (PA6) which is transparent for the applied laser radiation with another adherend being a thermoset carbon fiber-reinforced plastic. The application is addressed to use thermoplastic fasteners to join different materials to thermoset carbon fiber-reinforced plastic parts. The influence of different laser intensities and different amounts of introduced energies to the joint are investigated. Therefore, laser parameters such as scan speed and laser power are varied using a fiber laser and a scanner optic. The same laser source is used to pretreat the thermoset surface exposing the C-fibers before joining. The performance and the quality of the joints are evaluated by mechanical shear-tests and microscopic cross sections. The results show the significant influence of laser intensity and energy on damage-mechanisms but also the possibility to provide good quality joints reaching up to 13.8？MPa