Computer Simulation of Laser Parameters in Microfabrication

Abstract

Laser micromachining technology offers a promising alternative fabrication method for mass production of microfluidic channels. In this study, we performed a systematic investigation to understand the effect of various laser parameters and thermophysical properties of microfluidic substrate material (Poly(methyl methacrylate) (PMMA) ) in laser micromachining. A three dimensional transient energy equation was solved using finite element method where laser induction was represented as a moving heat source with Gaussian profile. The convergence and grid independence studies were performed for the developed model. The simulation results show that the profile of the channel and cut depth are the complex function of laser parameters such as laser beam radius, laser power and moving speed as well as thermo-physical properties of the substrate such thermal conductivity, density and specific heat. For a specific laser beam radius which depends on the distance between laser tip and the target substrate, the laser power and cut depth has linear relation. Larger beam radius create wider profile with lower cut depth. However the relation between the laser beam radiuses with cut depth are not linear. The higher convective heat transfer coefficient creates lower cut depth and smoother surface in the channel. The effect of specific heat does not have significant effect on the laser machining. This study will help in selecting optimum parameters for mass fabrication of microchannels.