Surface quality analysis of microchannels fabricated through laser micromachining on PMMA for microfluidic applications

Abstract

Micromachining is a widely employed technique for generating micro features across diverse applications. Laser micromachining has gained significant attention due to its inherent flexibility, precision, and ability to process a wide array of materials. In the era of miniaturization, laser has proven to be sustainable choice of process in the field of micromachining. Within laser machining, CO₂ laser machining is considered to be an economical option. However, challenges persist in achieving both a high surface finish and a variable cross-sectional profile for microchannels. This study focuses on the investigation, identifying and categorizing of defects in microchannels machined by laser on polymethyl-methacrylate. Laser parameters are systematically varied to optimize the surface quality of the machined channels. Microchannels, fabricated through a full factorial experiment, are visually assessed using an optical microscope. The channels with the highest and lowest ratings are selected for further confocal and scanning electron microscope (SEM) analysis to comprehensively study the identified defects. The surface roughness is found to be 0.675 µm for the high-quality channel. A good surface finish at both the valley and side wall, along with a well-formed edge bulge was found at this condition.