Injection mold and recycling process for waste plastics

CN121133039BActive Publication Date: 2026-04-21GUANGZHOU HAOSHUN MOLD TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
GUANGZHOU HAOSHUN MOLD TECH CO LTD
Filing Date
2025-09-16
Publication Date
2026-04-21

AI Technical Summary

Technical Problem

In existing injection molding technology, ejector pins tend to leave marks when ejecting the workpiece, affecting surface quality. Furthermore, the long waiting time during mass production leads to low efficiency.

Method used

Positive pressure air-assisted ejector pin ejection of workpiece is adopted. By setting pistons and hydraulic channels in the injection mold, positive pressure air is used to compensate in the cooling zone, and the ejector pin is moved slowly to avoid negative pressure deformation. Under positive pressure, it assists in demolding. Combined with springs, it provides flexible support to prevent marks from appearing.

Benefits of technology

It improves the molding quality and mold opening efficiency of injection molded parts, is suitable for mass continuous production, reduces waiting time, and ensures the surface quality of injection molded parts.

✦ Generated by Eureka AI based on patent content.

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    Figure CN121133039B_ABST
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Abstract

This invention relates to the field of waste plastic recycling and reuse, and discloses an injection mold for waste plastic recycling, including a fixed mold base, an injection base, and a moving mold base. The fixed mold base has an installation groove and a mold cover on the side facing the injection base. A piston is fitted inside the installation groove, and multiple ejector pins are vertically arranged on one side of the piston. The ends of the ejector pins extend into pin holes located at the bottom of the installation groove. During injection molding, the piston moves closer to the bottom of the installation groove, making the ends of the ejector pins flush with the openings of the pin holes near the mold cavity of the injection mold. When the mold is opened after injection molding, air is first injected into the area between the bottom of the installation groove and the piston, creating positive pressure. At the same time, the piston moves away from the bottom of the installation groove, causing the ends of the ejector pins to gradually leave the pin holes. The area between the pin ends and the injection molded workpiece is called the cooling zone. As the ejector pins leave, air can enter the cooling zone under positive pressure, compensating for the cooling zone and maintaining normal pressure.
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Citation Information

Patent Citations

  • Disposable in-mold forming vulcanization system for rubber products and molding vulcanization method

    CN109177258A

  • Injection mold device for plastic part and demolding method

    CN115782091A