Design and Analysis of a Thin Film Permanent Magnet Actuated Micro Pump
Chao Zhi*, Tadahiko Shinshi*, and Minoru Uehara**
*Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
**Magnetic Materials Research Laboratory, Hitachi Metals, Ltd., 2-15-17 Egawa, Shimamoto-cho, Mishima-Gun, Osaka 618-0013, Japan
In this paper we present the design, analysis and an experimental evaluation of a micro pump utilizing a 20 µm thick, 3 mm diameter Thin Film Permanent Magnet (TFPM). The pump includes an electromagnet that uses a magnetic closed circuit. The design of the electromagnet was optimized and was theoretically explained. A PolyDiMethylSiloxane (PDMS) diaphragm with a thickness of approximately 80 µm was used in the pump. The electromagnetic force on the diaphragmwas calculated using a finite elementmethod. Large deformation analysis was used to calculate the displacement of the diaphragm. The force and displacement measurements agreed well with those calculated by simulation. The performance of the fabricated pump was also evaluated. During pumping, the displacement of the diaphragm reached 500 µm, which is the same as the height of the chamber. Furthermore, because of the large displacement, the pump is bubble tolerant and self-priming. A maximum flow rate of 50 µL/min and a maximum pressure of 110 Pa were achieved. A square wave input signal was demonstrated to be more effective than a sinusoidal signal in generating a high flow rate.
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