METHOD FOR PREVENTING MATERIAL FROM BEING SCORCHED IN INJECTION MOLDING

摘要

PROBLEM TO BE SOLVED: To decrease scorching of a material remakably less than before by tracking down the cause of generation of carbonization of a resin in a plasticization cylinder and taking a step in cope with the cause. SOLUTION: In injection molding of a resin by means of an injection apparatus in which a plasticization screw 2 is rotatably and freely back and forth mounted in a plasticization cylinder 1, the contact face of the plasticization head 11 with a molten resin is treated with W-Ni plating. Contact faces of a torpedo 21 at the apex of the plasticization screw 2, a ring valve 22 and a sheet ring 23 with the molten resin are coating-treated with CrN. Sticking and retention of the resin on the contact faces are prevented from being generated by these treatments and the material is prevented from being scorched due to carbonization of the resin. A pneumatic powder removing hopper 15 for removing the particulate or powdery resin is provided on the hopper. A feeding pipe 16 for a gas for preventing the resin from being oxidized while the resin is plasticized is connected with the hopper 13.