Injection molding method and apparatus with reduced piston leakage
AssigneeTakata Corporation
InventorKaname Kono
Life of this patent
Estimating the term…
Abstract
A metal injection molding apparatus is provided with features which reduce the amount of metal which enters the drive mechanism of the apparatus. The apparatus contains a piston having the head and the shaft, the shaft having a diameter smaller than the diameter of the head. At least one piston ring circumscribes the piston shaft. The apparatus contains an injection chamber having an accumulation portion and a shaft housing portion. The shaft housing portion has openings in the sidewalls and a polygonal internal cross section. The accumulation portion of the injection chamber is maintained at a higher temperature than the shaft housing portion.
Claims10
A method of making an injection molded metal part, comprising:
- providing a metal into an accumulation portion of an injection chamber;
- maintaining the accumulation portion of the injection chamber at a first temperature above the liquidus temperature of the metal;
- maintaining a shaft portion of the injection chamber at a second temperature below the liquidus temperature of the metal;
- and
- advancing an injection member having a head and a shaft in the injection chamber to inject the metal from the accumulation portion into a mold cavity.
An injection molding apparatus, comprising:
- an injection chamber comprising an accumulation portion and a shaft housing portion;
- an injection member comprising a head and a shaft located in the injection chamber;
- a first means for heating the accumulation portion of the injection chamber to a first temperature above a liquidus temperature of a metal injected by the injection member;
- a second means for heating the shaft housing portion of the injection chamber to a second temperature below a liquidus temperature of the metal injected by the injection member;
- at least one ring attached to the shaft of the piston;
- and
- at least one opening in a side wall of the shaft housing portion,
- wherein the injection member comprises a piston, such that the head of the piston in a fully retracted position is located in the accumulation portion, and at least a portion of the shaft of the piston in a fully retracted position is located in the shaft housing portion;
- and
- wherein the accumulation portion of the injection chamber has a circular internal cross section and the shaft housing portion of the injection chamber has a polygonal internal cross section.
An injection molding apparatus, comprising:
- an injection chamber comprising an accumulation portion and a shaft housing portion;
- an injection member comprising a head and a shaft located in the injection chamber;
- a first means for heating the accumulation portion of the injection chamber to a first temperature above a liquidus temperature of a metal injected by the injection member;
- and
- a second means for heating the shaft housing portion of the injection chamber to a second temperature below a liquidus temperature of the metal injected by the injection member,
- wherein the accumulation portion of the injection chamber has a circular internal cross section and the shaft housing portion of the injection chamber has a polygonal internal cross section.
Dependencies are inferred from the claim text.