A numerical and experimental analysis of CO₂ laser micro-milling on PMMA sheet considering a multipass approach for microfluidic devices

Laser-assisted machining is an advanced manufacturing process that provides excellent cutting quality, flexibility, and precision. The current study used a CO₂ laser to create microchannels in polymethyl methacrylate (PMMA) sheets using a series of laser passes by varying parameters such as laser power (30–40 Watt), number of passes (1–4), and cutting speed (20–25 mm/s). A finite element analysis is performed using ABAQUS with subroutines such as Distributed Flux (DFLUX) and User Defined Field (USDFLD) to simulate and predict the upper and lower kerf width, kerf angle, and heat-affected zone (HAZ) during the process. Thermal analysis has been performed by considering the laser beam as body heat flux with a moving heat source. It has been observed that the HAZ tends to reduce with the increase of laser cutting speed. During the laser cutting process, the upper kerf width is found to increase with increasing laser power, as well as with increasing the number of passes at a given laser power and cutting speed. It is also predicted that when laser cutting speed increases, the kerf width for a given laser power decreases. The experimental and simulation results are in good agreement and the results demonstrated that the average percentage error in HAZ, kerf angle, upper kerf, and lower kerf width was 3.21 %, 5.06 %, 7.60 %, and 22.2 %, respectively. The results of this study have significance for the advancement of precise and state-of-the-art manufacturing for application in microfluidic devices.