A comparative evaluation of laser assisted drilling CFRP with improved machining mechanism

Drilling carbon fiber reinforced polymers (CFRPs) presents significant challenges due to high cutting forces and surface defects. To address this, laser-assisted drilling (LAD) has emerged as a pioneering technique, surpassing conventional drilling (CD). Experimental results unequivocally establish LAD's superiority. Notably, the cutting mechanism in CFRP transitions from compression fracture in CD to shear cutting in LAD, remarkably reducing cutting force by about 26%. This reduction is explained comprehensively, accounting for surface energy, frictional energy, and chip fracture energy. We introduce an innovative simulation model replicating the machined CFRP surface after laser processing, enabling detailed surface quality analysis in LAD. Drawing on elastic foundation beam theory, we formulate a mathematical model for orthogonal cutting in LAD, characterizing cutting forces. Combining these findings with experiments, we elucidate LAD's CFRP drilling mechanism, identifying six drilling stages by tool depth. Our investigation covers facets including cutting forces, temperatures, exit delamination, and hole surface quality, holistically evaluating LAD's benefits. This research sheds light on LAD's intrinsic drilling characteristics for CFRP, highlighting its potential for innovation and application in CFRP drilling. The combination of experimental validation, innovative modeling, and comprehensive analysis solidifies LAD as a breakthrough in advancing CFRP drilling. This study enhances our understanding of LAD's mechanics and its promise for broader industrial use.