Rotary Core Mold Restricting Mechanism for Undercut Release
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Solution Overview
Problem
Mold releasing defects occur in resin molding due to resin pressure causing the rotary core to be pushed into the mold main body, leading to core lines and movement failures in undercut parts, especially when the rotary core is designed with a curved slide-contact face.
Innovation Solution
A mold apparatus configuration that includes a restricting core to sandwich and restrict the rotary core during molding, allowing it to rotateally move away from the undercut part by releasing restriction, with planar contact faces and a cam mechanism for efficient movement, preventing core lines and optimizing the structure for resin pressure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a curved slide-contact face is formed on the rotary core to enable rotational movement for mold release, then the rotary core can rotate to separate from the undercut part, but resin pressure pushes the rotary core further into the mold main body causing interference and mold release failure
Solution Approach 1:
A restricting core is introduced as an intermediary component between the rotary core and mold main body. During molding, the restricting core prevents the rotary core from moving laterally into the mold main body. During mold release, the restricting core retracts to allow the rotary core to rotate freely. This mediator resolves the contradiction by enabling rotational movement when needed while preventing harmful lateral movement during molding.
Solution Approach 2:
The restricting core is designed to change its state dynamically between molding and mold release phases. During molding, it is in a restricted state (extending between rotary core and mold main body). During mold release, it transitions to an unrestricted state (retracting from between the components). This dynamic state change allows the system to adapt to different operational requirements, enabling both stable positioning during molding and free rotation during release.
2Reliability
If a gap is formed between the rotary core and mold main body to prevent interference during mold release, then the rotary core can move without interfering with the mold main body, but the rotary core moves to the side due to resin pressure creating a step and core line
Solution Approach 1:
The restricting core serves as a mediator that maintains a controlled relationship between the rotary core and mold main body. Instead of relying on a fixed gap that allows lateral movement, the restricting core actively prevents such movement during molding. This resolves the contradiction by ensuring both proper clearance for rotation and prevention of harmful lateral displacement that would create steps and core lines.
3Ease of operation
If the rotary core is designed with a curved slide-contact face to facilitate rotational movement, then mold release is enabled, but the curved surface is more prone to interference with the mold main body under resin pressure
Solution Approach 1:
The restricting core acts as a protective intermediary that shields the curved slide-contact face of the rotary core from harmful lateral forces during molding. While the curved face maintains its rotational capability, the restricting core prevents it from moving into the mold main body, thereby eliminating the harmful interference effect without compromising the rotational function.
Data Source
AI summary
The mold apparatus (1) includes: the stationary mold (12) of the mold main body (2) that molds the main body part (81); the rotary core (20) that molds the undercut part (82) and mold releases by rotationally moving in a direction separating from the undercut part (82); and the restricting core (40) that restricts movement of the rotary core (20) sandwiching between the stationary mold (12) and rotary core (20) during molding, and releases restriction of the rotary core (20) by moving in a direction exiting from between the stationary mold (12) and rotary core (20) during mold release of the rotary core (20) from the undercut part (82).