Additive Manufacturing of Micro-channels on a Silicon Substrate based on Coaxial Printing Dispenser with in-situ UV LED Curing

Micro-channels in MEMS can provide passage to liquid or gas for various applications. Conventional fabrication of micro-channels is by silicon etching or soft lithography. This paper proposes an alternative approach for fabricating micro-channels on a silicon or glass substrate based on coaxial printing by a needle dispenser with UV-LED for in-situ curing. In the present research, the coaxial nozzle consists of two parts: an inner needle for inner flow, which is air, and an outer needle for outer flow, which is UV curable polymer. A certain amount of UV curable polymer is extruded from the coaxial nozzle. With the assistance of UV LED fixed at the neighborhood and a transparent jacket fixed to the coaxial nozzle, a hollow tube segment can be formed. By matching the extrusion speed of segments and the dispenser printing speed, a continuous hollow tube can be printed on the silicon or glass substrate. This paper further proposes that vertical micro-channels with different inner diameters may be printed on substrate for MEMS applications by the coaxial printing method.