METHOD FOR PRODUCING RARE-EARTH SINTERED MAGNET AND MOLDING DEVICE

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The present invention provides a method for producing a rare earth sintered magnet and a molding device therefor that can stably mold molded bodies with less variation in unit weight even though a large magnetic field, for example, 1. 5 T or more is applied during press molding in the magnetic field, by disposing cavities. The method for producing a rare earth sintered magnet according to the present invention includes the steps of : 1) preparing a slurry including an alloy powder and a dispersion medium, the alloy powder containing a rare earth element; 2) disposing an upper punch and a lower punch in respective through holes provided in a die, thereby preparing a plurality of cavities enclosed by the die, and the upper punch and the lower punch, at least one of the upper punch and the lower punch being movable toward and away from the other one, at least one of the upper punch and the lower punch including an outlet for discharging the dispersion medium of the slurry; 3) applying a magnetic field in each of the cavities by an electromagnet in a direction substantially parallel to a direction in which at least one of the upper punch and the lower punch is movable, and then supplying the slurry into the plurality of cavities via slurry flow paths connected to slurry supply paths extending from an outer peripheral side surface of the die to each of the cavities, wherein at least a part of a portion of the slurry flow path passing through a magnetic field formed by the electromagnet is covered by an external magnetic field shielding material being capable of shielding the magnetic field; 4) producing a molded body of the alloy powder in each of the cavities by press molding in the magnetic field, the upper punch and the lower punch coming closer to each other while applying the magnetic field; and 5) sintering the molded body.