The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Nov. 04, 2003

Filed:

Sep. 28, 2000
Applicant:
Inventors:

Takahiro Kobayashi, Nagano-ken, JP;

Mamoru Miyagawa, Nagano-ken, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B22D 1/700 ;
U.S. Cl.
CPC ...
B22D 1/700 ;
Abstract

An injection molding method of a metal material in a liquid phase state, by which the material can be transferred, metered, and deaerated smoothly by operating the movement and rotation of the screw. After injection, retraction resistance made of the metal material that went into a clearance between the heating cylinder and screw flights is removed in advance by rotating the screw for a set number of times at a forward position. Then, the metal material in the liquid phase state is accumulated in a front chamber by forcing the screw to retract for a set distance, and applying a back pressure to the screw rotating at a retraction position, thereby starting transfer of the metal material. Subsequently, the rotation of the screw is stopped, whereupon the accumulation is completed. Then, the accumulated metal material is pressed by moving the screw forward. Injection is effected only when a material pressure reaches a set pressure within a preset forward distance of the screw, whereupon metering is assumed to have been completed.


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