Parameter Optimization for High-Resolution Microfluidic Channel Fabrication Using a Commercial Low-Cost MSLA Printer.

Vat polymerization-based 3D printing has emerged as a promising approach for the rapid, low-cost, and scalable fabrication of microfluidic devices; however, achieving high-resolution and fully clog-free microchannels using commercial resins remains challenging. In this study, we systematically investigate key printing parameters-including channel orientation, length, layer thickness, and exposure time-to elucidate their effects on channel openness, dimensional fidelity, and surface morphology using a commercially available low-cost masked stereolithography (MSLA) printer and printing resin, thereby establishing quantitative fabrication boundaries that define the transition from fully open to blocked microchannels in practice. Under optimized printing conditions, microchannels with characteristic dimensions exceeding 200 µm were fabricated in a reliable and clog-free manner using standard commercial resins. In addition, by implementing a size-compensated design strategy, we achieved the fabrication of complex droplet generator arrays with a minimum central channel width of 400 µm, while maintaining an internal dimensional deviation below 2.5%. These investigations significantly expand the practical applicability of low-cost MSLA 3D printing for microfluidic device fabrication, providing a scalable and accessible pathway for producing high-fidelity microchannels without reliance on custom resins or post-processing-intensive workflows.