Combined hot embossing and milling for medium volume production of thermoplastic microfluidic devices

Current methods for fabricating thermoplastic microfluidic devices are either appropriate for prototyping in research labs, or for mass production for commercialization purposes. However, methods for fabricating plastic microfluidic devices in medium volume production have not been demonstrated, and thus, creates a gap in manufacturing methods. A medium volume manufacturing method would be practical and necessary during the technology development phase when many fabricated devices may be required for testing and validation, but design modifications may still be required, thereby making mass production unnecessary and not economical. This study demonstrates the feasibility of combining hot embossing and milling methods to achieve medium volume production of thermoplastic microfluidic devices with high replication fidelity. Hot embossing parameters were tested and optimized on two different embossing systems and for two different plastics (COP and PMMA). Using these optimal hot embossing parameters together with improvements in epoxy mold fabrication and a streamlined milling procedure, a production rate of ∼50 devices per week was achieved during a proof-of-concept medium volume production run. Importantly, this approach also provides a flexible strategy that can accommodate prototype design changes without resulting in long development delays. Overall, results provide evidence that medium production levels can be performed in research labs and in industry, thereby providing an accelerated path to commercialization.