Fine die cast metallic parts

Abstract

A finished molded metal part is produced by an injection molding system includes a feeder in which a metal is melted and a first chamber into which a desired amount of melted metal is introduced. The molded metal parts can have extremely fine dimensions, small thicknesses, and indented or protruding surface features that are molded with such low porosity that no further milling/finishing operation is required before the part is used in its finished state.

Description

CROSS-REFERENCE OF THE RELATED APPLICATION [0001] This application is a continuation-in-part of application Ser. No. 09 / 160,330, filed on Sep. 25, 1998, titled “Method And Apparatus For Manufacturing Metallic Parts by Injection Molding From the Semi-Solid State”; application Ser. No. 09 / 160,976, also filed on Sep. 25, 1998, titled “Method and Apparatus for Manufacturing Metallic Parts by Fine Die Casting” which issued as U.S. Pat. No. 5,983,976, on Nov. 16, 1999, and provisional application Ser. No. 06 / 080,078, filed Mar. 31, 1998, the disclosures of which are hereby incorporated by reference into this application in their entirety.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The invention relates to fine die cast metallic parts, more particularly to fine die cast metallic parts produced by a process involving injection of a melted metal into a mold. [0004] 2. Description of the Related Art [0005] One conventional method used to produce molded metallic parts f...

AI Technical Summary

Benefits of technology

[0021] The above-described process and system provide a very precise control of the injection volume, to within ±0.5% by weight or less, because the injection volume is determined in accordance with the position of the piston and any gas that is present in the melted metal, which can be about 20% by volume, is forced out by operation the ram advancing, before the melted metal is injected.

[0022] Further, a molded metallic part made by the fine die-cast method according to the invention is more advantageous than molded metallic parts made by current thixotropic processes because conversion of metal into the thixotropic state takes more time. With the fine die-cast method according to the invention, the injection cycle time is reduced to about 30 seconds, a 50% reduction when compared to current thixotropic processes. Consequently, the molded metallic parts can be produced much more rapidly.

[0023] Also, the method of the present invention can be used to mold parts of a liquid material that are more preferred than parts molded from current thixotropic processes. They generally require less post-molding processing, given their more accurate molding volume and smooth surfaces. This permits a production pro

Problems solved by technology

Molded metallic parts having low densities are not generally desirable because of their reduced mechanical strength, higher porosity, and larger micro shrinkage.

It is thus difficult to accurately dimension conventional molded metallic parts and, once dimensioned, to maintain their shapes.

Moreover, molded metallic parts produced from conventional die casting have difficulty in reducing the resilient stresses developed therein.

It is difficult to accurately control all of the process parameters withi

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