Design, analysis and optimization of an electromagnetic actuator for a micro impedance pump

Abstract

This study designs and optimizes an electromagnetic actuator for use in a valveless micro impedance pump. The actuator is modeled to have an electroplated permanent magnet mounted on a flexible PDMS diaphragm and a planar copper micro-coil patterned on a bottom glass substrate. The constituent parts of the actuator, namely the diaphragm, the micro-coil and the magnet, are modeled, analyzed and optimized in such a way as to maximize the actuating force while simultaneously ensuring the mechanical integrity of the device. In performing the analyses, theoretical and mathematical models of the stroke volume and diaphragm deflection are developed based on thin plate theory. The design models are verified theoretically and numerically, and the relationships between the electromagnetic force, the diaphragm displacement and the diaphragm strength are systematically explored. Overall, the results reveal that in the optimized device, the target diaphragm deflection of 20 µm can be obtained using a compression force of 12 µN developed by a micro-coil input current of 0.8 A. The electromagnetic actuator proposed in this study provides an ideal solution for the pumping requirements of a variety of biomedical chips and microfluidic applications and therefore represents a valuable contribution to the ongoing development of lab-on-a-chip systems.