An axial flux electromagnetic micromotor

In this paper, the principle, design, fabrication and performance of an axi al flux electromagnetic micromotor are described. The stator of the micromo tors consists of six levels of copper windings and an alumina filling using a modified LIGA (Lithographic Galvanoforming Abforming)-like technology. T he rotor is a disc made of SmCo permanent magnetic alloy using the electro discharge machining (EDM) technique and it is magnetized with pairs of magn etic poles using a specially designed apparatus. The rotor and the stator a re assembled together to form the micromotor. The dimensions of the assembl ed motors are 1 mm and 2 mm in diameter and about 1.5 mm thick. The rotatio n speed of the micromotors can be adjusted from several hundreds to over te n thousand rpm and the rotation is reversible. The output torques of the mi cromotor are measured to be 1.5 muN m and 2.8 muN m for motors with diamete rs of 1 mm and 2 mm, respectively.