Numerical and experimental investigation on laser transmission welding of fiberglass-doped PP and ABS

Fiberglass-doped polypropylene (PP) and fiberglass-doped acrylonitrile butadiene styrene (ABS) are more difficult to be laser transmission welded than other pure plastic because of its low laser transmittance, and this paper aims to quantificationally investigate the relationships of welding parameters, molten pool area and shear strength in welding fiberglass-doped PP and fiberglass-doped ABS by simulation and experiment method. Firstly, comparing with previous researches, several technique difficulties in this welding experiment are pointed out. Secondly, a new hybrid heat source model is proposed to build three-dimensional finite element model for predicting temperature distribution and molten pool geometrical size by coupling Rotary-Gauss body heat source and Gauss plane heat source. Then, a group of taguchi experiment is completed to obtain the characteristics of welded joint, and to evaluate the precision of hybrid heat source model under various welding parameters. Furthermore, the mathematic relationships between molten pool area, laser energy per unit of area and shear strength are fitted out to search optimal welding parameter. Eventually, microstructure observation and fracture appearance analysis experiments are implemented to reveal the root cause of above relationships. This proposed hybrid heat source model and mathematical relationships exhibit commendable value for guiding practical production of laser transmission welding.