Coil winding process for radial gap type electromagnetic devices with cylindrical stator

This paper presents a fabrication process for forming a cylindrical stator incorporating micro-coils. Micro-coils are formed on a silicon substrate using the semiconductor processing technique. The substrate is then covered with a die having the shape of the stator teeth to fill the coils with a magnetic material by electroplating. After electroplating, the die and unwanted part of the core are eliminated. The substrate is also removed by etching it on the reverse side to obtain a sheet in which coils and teeth have been formed. After a sacrifice layer is formed on the surface of a separately fabricated 2-pole magnetized permanent magnet rotor, the sheet is wound utilizing magnetic force. This is inserted into a die and the gaps are filled with a magnetic material to form a core back to complete the cylindrical stator. Using this process, a prototype of an integrated stator and rotor were fabricated in an integrated manner. They were fixed to a housing and the sacrifice layer was eliminated to complete the generator. The voltage induced by generator rotation was measured