Numerical simulation of water jet–guided laser cutting of carbon fiber–reinforced plastics

Abstract

Carbon fiber–reinforced plastics are now widely used in various industries because of its excellent properties. Although milling and drilling are the dominating processing methods for carbon fiber–reinforced plastics at present, laser beam machining, as a wear-free, contactless and flexible process, is considered a promising alternative method. However, the thermal damage is one of the most important issues for laser beam machining of carbon fiber–reinforced plastics because of the significant difference in thermal properties of carbon fiber and matrix. Water jet–guided laser technique has been proved an effective technique to reduce heat damage. Nevertheless, there are few studies about carbon fiber–reinforced plastics processing with water jet–guided laser to date. It is important to understand the mechanism of interaction between water jet–guided laser and carbon fiber–reinforced plastics. Hence, a three-dimensional finite element model was developed to investigate the transient thermal process. The influence of scanning speed on the surface appearance, heat-affected zone and shape of the cross section was illustrated. Experiments with same process parameters were conducted to validate the model. Based on the finite element model and experiments, the mechanism of material removal was explained. The epoxy is considered to be removed once it reaches the melting point and the carbon fiber is removed at the sublimation temperature. Because of the strong cooling effect of water jet, there is nearly no heat accumulation between pulses, leading to the constant heat-affected zone width at different scanning speed. The kerf sidewall is relatively vertical due to the homogeneous power distribution in water jet. The results demonstrate that water jet–guided laser cutting of carbon fiber–reinforced plastics has some advantages than traditional laser beam machining and is a potential processing method for carbon fiber–reinforced plastics.