Experimental investigation of nanosecond laser Machining of 3D printed carbon fiber reinforced polymer (CFRP) composite

Abstract

Carbon fiber reinforced polymer (CFRP) composites are widely used in automotive and aerospace applications due to their high specific strengths, high fatigue and creep resistance, and excellent corrosion resistance. Additive manufacturing (AM) or 3D printing has opened new ways of manufacturing complex 3D parts using CFRP composites. As a result, researchers have gained interest in the machining or post-processing of 3D-printed CFRP composites. This study aims to investigate the feasibility of using a nanosecond laser for machining single craters or blind holes and slots on 3D printed CFRP samples and understand the effects of important process parameters on feature dimensions, (i.e., crater diameter, slot width, crater/hole depth, and slot depth), heat affected zone (HAZ), and surface quality of the machined features. A 1064 nm wavelength laser system with a focal length of 160 mm was used, whereas the number of pulses, laser energy level, and back-and-forth laser passes are varied. The heat-affected zone is found to be influenced by the laser energy level as compared to the number of pulses. It is found that for the same number of pulses, there is a clear sign of an increase in HAZ with the increase in laser energy level. With the increase in the number of pulses, the hole or slot edge becomes more defined and clearer, whereas the HAZ is mostly determined by the energy level. There is an accumulation of molten or removed materials at the edge of holes or slots causing jagged edges of machined features, which gradually diminishes when the edge becomes smoother for a higher number of pulses, or accumulated materials evaporate away at the higher setting of energy level. Finally, it is found that the nanosecond laser system is capable of machining quality holes and slots on the 3D-printed CFRP composite. To obtain features with well-defined profiles and minimal heat-affected zone, an understanding of the effects of laser process parameters is important.