Laser micromachining on PMMA: an efficient fabrication of microchannels for sustainable microfluidic devices

Abstract

Microfluidic devices showcase miniature technology to transform industries and promote sustainability by precisely manipulating small fluid volumes. Laser micromachining is widely used to create precise microchannels for various applications, including microfluidic devices. The present work aims to investigate the surface quality of the microchannel fabricated on polymethylmethacrylate substrate using a CO<inf>2</inf> laser. The laser parameters, such as power, machining speed, number of pass and laser focus distance, were varied to create the microchannel and the quality is investigated in two different stages. The first stage was performed with the help of an optical microscope, and further investigations with the aid of confocal and scanning electron microscope. A novel approach of rating the microchannels by visual inspection is introduced in the first stage of investigation. A visual rating is given for all the microchannels considering the edge bulge and surface quality of the microchannel at valley and side wall. Selected microchannels are further investigated in detail to understand the causes of various surface defects. The highest surface quality of 0.675 µm was obtained with laser power 12 W, machining speed 25 mm/s, number of pass 2 and the Z value is 17 mm. The findings will help attain the optimum process parameters for the laser micromachining of polymethylmethacrylate to develop various microfluidics devices. The novel approach of visual rating of the microchannels can shorten the time for the surface quality analysis and fasten the production. © The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024.