Analysis and fabrication process of an electromagnetically actuated valveless micropump with two parallel flexible diaphragms

This article presents a parallel dynamic passive valveless micropump, which consists of three layers-valveless pump body, diaphragm, and electromagnetic coil. The valveless pump body is wetly etched in a silicon wafer, the diaphragm is a polydimethyl siloxane (PDMS) film spun on a silicon wafer with embedded permanent magnet posts, and the coil is electroplated on a silicon substrate. Under the actuation of the magnetic field of the coil, the flexible diaphragm can be displaced upwards and downwards. In this article, after analysing magnetic and mechanical characteristics of the flexible membrane and direction dependence of the nozzle, a micropump is designed. In addition, the relative length (L/d) of the micropump's nozzle is 4. A 7x7 array of permanent magnetic posts is embedded in the PDMS film. The two diaphragms work in an anti-step mode, which can relieve the liquid shock and increase the discharge of the micropump. ANSYS (R) and Matlab (R) are adopted to analyse the actuation effect of the coil and the flow characteristic of the micropump. Results show that when actuated under a 0.3 A, 100 Hz current, the displacement of the diaphragm is > 30 mu m and the discharge of the micropump is similar to 6 mu l/s.