Fabrication of Micro-channels on Polymethyl Methacrylate (PMMA) Plates by Thermal Softening Process Using Nichrome Wire: Tool Design and Surface Property Evaluation

Abstract

Microfluidics, emerging system of fluid-handling technology by using micro-channels are being applied to diverse fields due to everyday demand. To overcome high volume market needs; low cost and fast processing methods are necessary to fabricate microfluidic devices. There are many ways to produce the necessary channel and feature dimensions using photolithography to milling. This study focus on the fabrication of narrow cylindrical channels having a dimension of microns (width and depth) in a poly(methyl methacrylate) substrate by a thermal softening process using the Joule heating effect of nichrome wires. The channel fabrication tool is designed and developed to generate localized heat on the substrate with a high repetition rate by using the moving hot nichrome wire as a function of feed rate (600-9000 mm/min) in a CNC machine. 3D optical profilometer study reveals that the channels are cylindrical and smooth. By increasing the feed rate, the width and depth of the microchannels are controlled from 230-80 μm, and 60 to 17 μm, respectively. These results suggest that the thermal softening process using a nichrome wire is a promising tool for the fabrication of micro-channels on flexible polymeric substrates.