Resin Retainer Molding Sequence to Prevent Annular Deformation
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Solution Overview
Problem
The existing methods for manufacturing outer-ring guided resin retainers with two annular sections by injection molding often result in radial deformation of the annular sections due to the load applied during the extraction of slide cores, leading to potential operational failures and accuracy issues in the outer peripheral surface.
Innovation Solution
The method involves using an injection molding die with a fixed-side and movable-side cavity forming mold, along with slide cores that have protruding portions to support the annular sections axially, allowing for the extraction of pocket-forming protruding portions before mold opening, which prevents radial deformation by fitting concave and protruding portions between the molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If slide cores are used for forming pockets and extracting the molded article, then the undercut pocket can be formed and the article can be removed, but burrs are generated at the parting lines and radial deformation occurs during extraction
Solution Approach 1:
The invention performs the extraction action in a predetermined sequence: first extracting the slide cores that form the pockets, then opening the mold to remove the article. This preliminary action prevents deformation by ensuring the slide cores are fully extracted before the mold opens and the article is subjected to removal forces.
Solution Approach 2:
The extraction process is segmented into distinct stages: (1) extraction of slide cores while mold remains closed, (2) opening of mold, (3) removal of article. This segmentation allows each operation to be performed under optimal conditions, preventing the simultaneous application of forces that cause radial deformation.
2Productivity
If slide cores are extracted while the mold is open, then the molded article can be removed, but the annular sections deform radially due to applied load
Solution Approach 1:
The invention performs the critical extraction action before the mold opens. The slide cores are extracted while the mold remains in the closed position, maintaining support for the molded article. Only after extraction is complete does the mold open, allowing rapid removal without deformation risk.
3Productivity
If the mold opens immediately after injection, then the molded article can be ejected, but slide cores cannot be properly extracted from the pockets
Solution Approach 1:
The invention introduces a dynamic, multi-stage extraction sequence: first extracting pocket-forming slide cores while the mold remains closed (when material is still warm and flexible), then opening the mold for article removal. This dynamic approach adapts the extraction timing to the physical state of the molded material.
Data Source
AI summary
Provided is a method of manufacturing a resin retainer having two annular sections. A fixed-side cavity forming mold has a first axial mold surface that is in contact with an axial end surface of a first annular section of the annular sections of a resin retainer having two annular sections, and a first protruding portion protruding from the first axial mold surface. A movable-side cavity forming mold has a second axial mold surface that is in contact with an axial end surface of a second annular section of the annular sections of the resin retainer, and a second protruding portion protruding from the second axial mold surface. A slide core sliding step is performed in which slide cores are slid toward an outer diameter and pocket-forming protruding portions of the slide cores are extracted from a pocket of the retainer, and then a mold opening step is performed in which the movable-side cavity forming mold is opened relative to the fixed-side cavity forming mold.