Prediction of molten area in laser transmission welding of thermoplastic polymers

The prediction of the molten area is of great significance for laser transmission welding (LTW) of polymers. The purpose of the present study is to develop a mathematical model for LTW of polymers. The cross-sectional molten area of weld can be calculated through this model. The mathematical model was developed and deduced on the basis of the physical heat calculation formula. Subsequently, the model was validated by laser irradiating polyamide-66 (PA66) plaque containing 30 wt-% carbon fibre (CF), as well as LTW of PA66 containing 30 wt-% glass fibre with PA66 containing 30 wt-% CF. A viewpoint that the melt area of the upper layer to the bottom layer ratio (S-U/S-L) depends on the allocation proportion of the line energy between the interface during LTWof thermoplastic polymers was proposed. The model can well predict the molten area and help optimise process parameters during LTW of polymers.