The Effects of Cryogenic Surroundings on Thermal-induced Damage in Laser Grooving of Fiber-reinforced Plastic

The traditional cutting of fiber-reinforced plastics causes serious concern of tool wear. The merits of narrow cuts and flexible path of lasers lead to the application of the shaping operation of composite material after curing. However, laser-induced thermal damage is often produced. It leads to poor assembly tolerance and long-term performance deterioration. The current study derives the concept of laser machining in a cryogenic environment. The anisotropic heat affected zone (HAZ) associated with cryogenic parameters is experimentally and analytically investigated for both principal-axis and nonprincipal-axis grooving in the example of unidirectional Carbon/Epoxy laminates. In principal-axis grooving, an analytical model based on a moving point heat source with a Mirror Image Method and immersed heat source can illustrate the effect of cryogenic surrounding on HAZ, while Finite Difference Method (FDM) is applied for prediction in the case of nonprincipal-axis grooving. The results reveal that the extent of the HAZ can be reduced by the proposed use of a cryogenic environment in laser machining.