| 摘要 |
PURPOSE: To produce a resin bonded magnet having excellent magnetic characteristics with high productivity and moldability by charging magnetic compd. powder into a metal mold and pressurizing the powder while applying ultrasonic vibrations to the metal mold and punches under specific conditions, then further, pressurizing the powder under a specific pressure. CONSTITUTION: The compd. powder 6 formed by coating magnetic powder (an average grain size of about 0.5 to 350μm) with a thermosetting resin (epoxy resin, etc.) is fieled onto the lower punch 8 in the metal mold 9 for press molding having a magnetizing coil 7. While the ultrasonic vibration of a frequency of 10 to 40KHz and amplitude of <=100μm is applied on the upper punch 5 by an ultrasonic horn 4, the powder is pressurized for >=0.5 second under pressurizing force of <=100kg/cm<2> . Then, the ultrasonic vibration is stopped and the forming is executed at the pressurizing force of >=100kg/cm<2> . As a result, the heating of only the compd. powder 6 without heating the metal mold 9 is made possible and simultaneously, the compd. powder 6 charged into the metal mold 9 is made uniform within the metal mold 9. |
