MANUFACTURE OF RARE EARTH BOND MAGNET AND INJECTION MOLDED OBJECT

摘要

PROBLEM TO BE SOLVED: To increase the dimensional accuracy of a rare earth bond magnet by injection-molding a compound melt including magnetic Sm-Fe-N system alloy powder and resin in a specified metal mold through a gate having an opening area of a specified dimension or below. SOLUTION: 100 pts.wt. of Sm-Fe-N alloy magnetic powder treated with silane coupling and 9 pts.wt. of nylon resin are mixed and then kneaded at 220 deg.C to make a compound melt. The compound melt is injected into a specified metal mold through a gate having an opening area of 1.0 mm2 or below to fabricate an injection molded object of a radical anisotropic magnet in the shape of a C-type roofing tile at a nozzle and cylinder temperature of 250 deg.C. By this method, injection molding through a gate area of 0.5 mm2 is possible and thereby a small-size and light-weight complicated rare earth bond magnet 5 can be manufactured with high dimensional accuracy.