| 摘要 |
PURPOSE:To mold economically a gear with excellent surface smoothness, durability, etc., by a method wherein a mold wherein the mold wall face forming the mold cavity is coated with a heat insulating layer consisting of a heat- resistant polymer with a thermal conductivity of a specific value or lower is used, and a thermoplastic resin is injection-molded. CONSTITUTION:A mold wall face forming a mold cavity of a main metal made is coated with a heat insulating layer consisting of a heat-resistant resin with a thermal conductivity of at most 0.002cal/cm.sec. deg.C and with a thickness of 0.01-2mm, is used, and a thermoplastic resin is injection-molded by using this mold to form a gear. In use of this mold, it is extremely effective to decrease deposits caused by deposited substances generated when molding is performed by using polyacetal. |
