Patent ID: 11651893

Abstract:
Provided are molds for polar anisotropic ring-shaped bonded magnet molded articles which enable the production of bonded magnet molded articles with a high degree of roundness and only slight distortion, without the need for mold modification and preparation of a test mold, and a method of preparing such molds. The present invention relates to a method of preparing a mold for a polar anisotropic ring-shaped bonded magnet molded article, the method including: 1) determining the shrinkage length (Tc) of a desired polar anisotropic ring-shaped bonded magnet molded article using the following equation: Tc=T×(α1/100−α2/100); 2) determining the radius (Dm) of a magnetic pole portion of a mold cavity using the following equation: Dm=D/(1−α2/100); and 3) defining the outer peripheral shape of the mold cavity from the Tc, the Dm, and the number (P) of magnetic poles of the molded article.