NOVELTY - A plastic article is molded by providing a mold cavity between relatively movable mold parts, and injecting a predetermined dose of plastic material to the mold. The mold cavity is fully closed by moving mold parts (18a, 18b) relative to one another.
USE - For molding plastic articles, e.g. compact disks, digital versatile disk, vehicle body, and instrument panels.
ADVANTAGE - The method achieves lower levels of in-molded stress, and reduced cycle times as a result of shorter injection period and the sympathy between component cooling time and wall thickness.
DETAILED DESCRIPTION - Molding plastic article comprises providing a mold cavity between relatively movable mold parts. A predetermined dose of plastic material sufficient to form the finish formed particle, is injected to the mold prior to full closure of the mold cavity. The injected plastic material covers only a minor proportion of the mold cavity to a thickness greater than that of the finish formed article. The mold cavity is fully closed by moving the mold parts relative to one another. The closing of the mold provides the necessary pressure to cause the plastic material to flow, covering the remaining area of the mold cavity and provide the article with its finish formed thickness.
DESCRIPTION OF DRAWING(S) - The figures show a plan view of the injection molding machine, and a position of the mold parts.
Mold parts (18a, 18b).
