The extent of laser-induced thermal damage of UD and crossply composite laminates

Composite materials exhibit poor quality cut surfaces due to spalled fibres, fuzzing, and delamination when routed by conventional tools. Laser beam cutting offers an ideal means for the cutting of fibre composite materials, being a non-contact and virtually force-free manufacturing method. However, in the shaping operation of composite materials after curing, thermal damage associated with laser energy can be produced. It leads to poor assembly tolerance and long-term performance deterioration. In the current investigations, 3-dimensional anisotropic heat conduction models based on moving point heat source for thermal analysis are presented to predict heat affected zone (HAZ). Also, the conductivity models allow to consider the anisotropic heat conductivity for unidirectional (UD) and [0/90] laminates. Taking the immersing heat source and Mirror Image Method into account would further improve the prediction of HAZ. Extensive experiments were conducted on composite materials to examine HAZ, and compared with experimental results. The analytical results show a good agreement with experiments.