| 摘要 |
PURPOSE:To improve the durability of an insulating collar, by a method wherein a resinous material consisting of nylon 66 in which glass staple fibers are mingled is injection-molded with a mold having either a plurality of gates, which are on a plane intersecting perpendicularly to the central axis of the boss part of the insulating collar, are near the boss part and are almost at regular intervals, or a continuous gate. CONSTITUTION:When a resinous material, i.e., a resin, consisting of nylon 66 in which glass staple fibers are mingled is injected at a fixed pressure through a sprue 64, the head of resin-flow is led into the sprue 41, and sludge and the like are carried away and are pushed into a sludge well 68. After that, the resin not including the sludge is led into runners 66 and is filled into a runner lock part 70, following which the resin is led into a cavity 72 through pin point gates 74. At this time, after the resin-flow is filled into the boss part of an insulating collar, the resin is allowed to flow radially from the inner peripheral side of a flange part toward the outer peripheral side thereof. The head of the resin-flow flows toward the periphery of the flange part, and the resin cooled and the sludge concentrates on the surface of the periphery. Therefore, a weld line is not produced on the surface of the insulating collar. |
