Miniaturization of Hydrocyclones by High‐Resolution 3D Printing for Rapid Microparticle Separation

Hydrocyclones are a simple and powerful particle separation technology, widely used in macroscale industrial processes, with enormous potential for miniaturization. Although recent efforts to shrink hydrocyclones to the centimeter scale have shown great promise for passive and high‐throughput microparticle separations, further miniaturization is constrained by limited understanding of the impact of device size scale and design on separation performance, and challenges in realizing the complex internal structures of hydrocyclones at small size scales using conventional microfabrication techniques. Here, fundamental scaling issues for hydrocyclones with sub‐millimeter critical dimensions are investigated, and the first microscale hydrocyclones with critical feature size as small as 250 µm are demonstrated by taking advantages of 3D printing using stereolithography coupled with digital light processing. The resulting devices are shown to provide high separation efficiency for particles as small as 3.7 µm while operating at high flow rates up to 40 mL min−1, with scaling analysis suggesting that sub‐micrometer particle separations can be achieved with further miniaturization, potentially making the technology suitable for the rapid isolation and concentration of both inorganic and biological nanoparticles. Microscale hydrocyclones fabricated by high‐resolution additive manufacturing support the separation of micrometer‐sized particles at bulk flow rates up to 40 mL min−1, enabling efficient isolation and concentration of microparticles in a simple, passive, and robust process that offers exceptionally high throughput together with the potential for further scaling to improve separation size limits.