Patent ID: 9126358
Filing Date: 2015-09-08
Classification: B29C,B29K

Abstract:
1. A method of improving the appearance of a foaming injection molding product, comprising the following steps of: closing the moving mold and the fixed mold, and setting a clamping force on the closed mold, wherein a mold cavity is formed between the moving mold and the fixed mold and the closed mold does not need specific leakproof structures; initially inflating the mold cavity with high pressure and high temperature gas prior to injecting molten resin and until an air pressure in the mold cavity reaches 16-25 MPa and a temperature of the high pressure and high temperature gas is between 60-200° C.; injecting molten resin that contains foaming agent into the mold cavity while continuously inflating high pressure and high temperature gas; and after injection is completed, stopping inflating high pressure and high temperature gas and simultaneously releasing pressure, wherein the step of releasing pressure includes the step of opening the mold, wherein only one slit is opened between the moving mold and the fixed mold at the beginning of opening the mold, while the central non-solidified molten resin along a wall thickness in the product expands and foams to a desired thickness, then, cooling and taking out the finished product; wherein a total time of inflating the mold cavity with high pressure and high temperature is 5-8 s.