Toward Rapid Prototyping of High-Aspect-Ratio Sub-$\mathbf{100}-\mu \mathbf{m}$ PMMA Microfluidic Devices: Optimization of CO2 Laser Machining and Solvent-Assisted Thermal Bonding

In this work, optimization of CO ₂ -laser machining and solvent-assisted thermal bonding of PMMA [poly (methyl methacrylate)] sheet for rapid prototyping of microfluidic devices with sub- 100-μm and high-aspect-ratio (AR) feature is reported. Design of experiments (DOE) was used to optimize the set of cutting parameters that allowed us to achieve unprecedented minimum channel width of 57.5 μm with a high AR of 3.5:1 having smooth inner surfaces in contrast to Gaussian-shaped channels with rough inner surface, cut by conventional engraving-mode laser machining.