Patent ID: 6619370
Filing Date: 2003-09-16
Classification: B22D,Y10S

Abstract:
A method for semi-molten metal injection molding of a thin molded product, the method comprising the steps of:preparing a semi-molten mixture which is a magnesium alloy, wherein the semi-molten metal mixture is formed in a cylinder by heating and semi-melting the material charged by a screw from the back side of the cylinder while the screw is agitating the material in the cylinder; injecting the semi-molten metal mixture into a mold cavity in the mold wherein the semi-molten metal mixture is pressurized in a front end portion in the cylinder by pushing the screw toward the nozzle of the cylinder, and injected from the nozzle into the mold cavity through a product gate which is throttled in the mold communicated to the nozzle, wherein the mold cavity comprises a product portion for molding the thin molded product which portion has at least one of a wall thickness, between opposite surfaces thereof, of not more than 1.5 mm in 50% or more of the surface area of a product portion and a wall thickness, between opposite surface thereof, in a ratio of not more than 0.75 mm of the volume in mm3 of the product portion divided by the area in mm2 of both opposite surfaces of the product portion, and the semi-molten metal mixture injected into the product portion has an average grain size of a solid phase set to be not more than 0.13 times an average thickness of the product portion, solidifying the semi-molten metal mixture in the mold cavity to mold the thin molded product in the product portion of the mold cavity; and releasing the thin molded product from the product portion of the mold.