Design and Processing of Micro-droplet Chips based on Micro-milling Technology

This study investigates the design and fabrication process of microfluidic droplet chips based on micromilling technology, focusing on optimizing microchannel structure design and processing techniques. For the basic Y-shaped channel, three microchannel structures were designed and evaluated, with droplet generation experiments verifying their ability to form continuous, stable droplets at corners, completing chip fabrication. Experiments show that micromilling is suitable for processing microchannels on PMMA material, with cross-sectional dimensions influenced by tool size, processing parameters, and material properties, offering advantages of low cost and high flexibility compared to photolithography. The chip structure was designed using UG software, with CAD drawings exported and tool paths and processing parameters set via Autodesk Artcam Premium 2018, then transferred to micromilling equipment for PMMA board processing. Key parameters, such as spindle speed and feed rate, were optimized by analyzing microchannel surface roughness to establish stable process conditions. After chip fabrication, two fluids of different densities were injected into separate microchannels for droplet generation experiments, where the higher-density fluid encapsulated the lower-density fluid to form independent, continuous droplets, ultimately identifying the optimal microfluidic droplet chip structure. This study provides theoretical and practical foundations for efficient, low-cost microfluidic droplet chip fabrication.