초록 ▼

A method for producing a handle-shaped molded article (1) having a thick grip portion (2) and at least one thick fitting portion (3) by injection molding using an injection molding apparatus (10) equipped with a mold having a cavity (60), a resin gate (46) provided in a portion (62) where the fittin

A method for producing a handle-shaped molded article (1) having a thick grip portion (2) and at least one thick fitting portion (3) by injection molding using an injection molding apparatus (10) equipped with a mold having a cavity (60), a resin gate (46) provided in a portion (62) where the fitting portion is to be formed and a gas inlet (48) provided in a portion (64) where the grip portion is to be formed. A hollow structure (4) is formed in the grip portion (2) and a solid structure is formed in the fitting portion (3) by injecting a molten resin into the cavity (60) through the resin gate (46), thereby filling molten resin in a fitting portion-forming cavity zone formed of that portion (62) of the mold where the resin gate is provided and the fitting portion is to be formed and further filling molten resin in part of the rest of the cavity. A pressurized gas is introduced into the cavity (60) through the gas inlet (48) while maintaining an injection pressure, P, at a predetermined value, the injection pressure, P, being defined by P=F/S wherein P is an injection force and S is a cross-sectional area of a screw (12) of the injection molding apparatus, and maintaining the injection pressure and gas pressure in the gas inlet (48) at predetermined values until the molten resin is cooled and solidified.

대표청구항 ▼

A method for producing a handle-shaped molded article having a thick grip portion having a hollow structure and at least one thick fitting portion having a solid structure by injection molding by means of an injection molding apparatus equipped with a mold having a cavity, a resin gate provided wher

A method for producing a handle-shaped molded article having a thick grip portion having a hollow structure and at least one thick fitting portion having a solid structure by injection molding by means of an injection molding apparatus equipped with a mold having a cavity, a resin gate provided where the fitting portion of the handle-shaped molded article is to be formed and a gas inlet provided where the grip portion of the handle-shaped molded article is to be formed, which comprises: injecting a molten resin into the cavity through the resin gate, thereby filling molten resin in a fitting portion-forming cavity zone formed of that portion of the mold where the resin gate is provided and the fitting portion is to be formed and further filling molten resin in part of the rest of the cavity, introducing a pressurized gas into the cavity through the gas inlet while maintaining an injection pressure, P, at a predetermined value, the injection pressure, P, being defined by P=F/S wherein F is an injection force and S is a cross-sectional area of a screw of the injection molding apparatus, and maintaining the injection pressure for exerting a pressure on the resin in the fitting portion-forming cavity zone and a gas pressure in the gas inlet at predetermined values until the molten resin is cooled and solidified.