Laser Micromachining of Microchannels On Various Microfluidic Substrates

Abstract

Recent years, laser micromachinig has become a promising technology for mass production of microfluidic channels in various polymeric substrates. However excessive roughness of channel surface, lack of control of process parameters and nonuniformity of channel geometry are the ongoing challenges. In this research, we studied the effect of laser system parameters on the channel characteristics. A commercial MUSE laser system was used for machining of three widely used microfluidic substrate to create microfluidic channels. Muse Full Spectrum laser system consists of a 45W laser tube with three degree of freedom (lateral, longitudinal and vertical). Three laser system parameters - speed, power, focal distance and number of passes are varied to fabricate straight microchannel on glass, PDMS and PMMA. The results show that higher speed produces lower depth while higher laser power produces deeper channel regardless of the substrate materials. However for same speed and power, PDMS channel had the roughest surface and PMMA had smoother surface. On the other hand, number of passes produces uniform and wider channel on the PMMA. Out of focus laser cut produces wider but shallower channel. In higher power and slower speed, glass breaks. The results also show that slight heat treatment can reduce surface roughness. This comprehensive experimental investigation can provide guidance for the substrate material based mass production of microchannels.