| 摘要 |
PURPOSE:To provide a method of molding synthetic resin which lessens a residual internal stress in a case body of which the upper side is opened, and also prevents a warp of an opened part. CONSTITUTION:On the occasion of molding a vessel body 1 having a flange edge 2 formed in an upper opened part, projections 4 having a larger thickness than the wall surface 3 of the vessel body 1 are provided from the bottom side to the flange edge 2 on the outer periphery of the vessel body 1, and molten synthetic resin is injected from a resin injection hole 5 formed in the projections 4 on the bottom side of the vessel body 1. When the molten synthetic resin is injected to a prescribed degree into a cavity of a mold and when the molten synthetic resin is not set yet, gas of a high pressure is injected from the resin injection hole 5. The gas reaches the inside of the flange edge 2 in the end part through the inside of the projections 4 and a vacant space is formed in the meantime. |
