A finite volume model for laser-soot interaction for a laser transmission welding process Available to Purchase

Laser transmission welding (LTW), a technique to join thermoplastic components, involves a laser beam passing through a laser-transmitting part being absorbed by a laser-absorbing part at the weld interface. The heat generated at the interface melts a thin layer of the plastic in both parts and forms a joint. Laser-absorbing agents such as dyes or soot particles are added to the laser-absorbing part to make it absorbing to the laser beam. Thermal and optical interaction of the soot particles and polymer with laser beam determines heating, melting, and consequently welding of plastics. To form a strong bond, it is important that the weld interface be exposed to sufficient heat to melt the polymer without degrading it. This paper investigates the thermal response of soot particles to a diode laser heat source. A thermal model is presented herein for a soot particle that is surrounded by a semi-crystalline material (PA6) and solved using finite volume technique. The results are then compared to the ones obtained from a finite element analysis solved with a commercial software (ANSYS^®). The micro-scale model predictions for the peak temperature of the soot particle appear to be reasonable when compared with the results of the macro-scale finite element models for the same process parameters and set up developed in the previous work of the authors.