In this study, ultrasonic vibration compaction of a soft magnetic composite (SMC) has been investigated. The importance of the SMC application to the electromagnetic industry has been increasingly recognized because it has advantages of lower eddy current loss and motor design with a three-dimensional (3D) magnetic core. However, SMC's have not yet reached the stage of practical use because of their lower density than the density of conventional electrical steel sheets. To improve the density of the SMC and reduce the friction between die and powder during the compaction process an ultrasonic compaction method was used. The high-power ultrasonic vibration system of 2.5 kW with six transducers was designed to form a high-density SMC magnetic motor core effectively. To achieve the optimal compaction condition of the SMC, effects such as vibration amplitude, pressure, position of compaction, and ratio of diameter to height were also investigated. The results showed that the density of the SMC could be improved by about 7% under the determined optimal condition. Moreover, to verify the effectiveness of the proposed method, the fabricated SMC core was embedded into an electrical motor and a 5% improvement of motor performance was achieved.

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