Examination of flex PCB configuration for a winding of a magnetic levitation motor

Small cooling fan failures are attributed to bearings. If a propeller rotates without any contact by magnetic levitation technology, high-speed rotation and long durability can be achieved. Thus, the authors are developing a small size maglev type motor. The Axial force/Torque Motor (AFTM) can generate axial bearing force and drive torque force in one unit. To increase the filling rate and manufacturing accuracy of winding, we used flex Printed Circuit Board (PCB) technology for AFTM. Coils are formed by winding the flex PCB around the back yoke. To higher manufacturable and improve the performance of AFTM, it is desirable to make flex PCB patterns correctly and increase the occupation ratio of copper. In this paper, we investigated the manufacturable layer configuration of special flex PCBs. Several prototypes with a different cover and copper thickness were manufactured and evaluated. We succeeded in producing a printed pattern with a copper thickness of 50 µm and a polyimide thickness of 5 µm. We could obtain a high filling factor.