| 摘要 |
PURPOSE:To contrive to save the weight of a product and reduce the of molding stock without impairing appearance quality and lowering commercial value by a method wherein a thicker walled part, a gradually changing wall thickness part and a thinner walled part are provided in the order named in the descending scale. CONSTITUTION:Resin, which is injected from a hot runner 7 through a sprue 6, passes through a film gate 5f and a film gate 5e in order to be filled in a cavity 5 from an upper surface molding cavity 5a. When the resin solidies, a band-like film gate part 1e and a hand-like film gate runner part 1f are produced at the upper part of a bumper. In this case, an upper surface part 1a and a vertical surface part 1b are mode to be comparatively thicker walled part having the thickness such as about 3.8mm and a corner part 1d is made to be comparatively thinner walled part having the thickness such as about 2.8mm. Further, an intermediate lower surface tilting part 1c is made to be gradually changing part B, in which the wall thickness is changed, for example, in a certain proportion. |
