Mold Core Pin Sleeve Rotary Release Mechanism
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Solution Overview
Problem
Existing molding apparatuses face challenges in stripping workpieces with undercuts due to the core pin material preventing axial removal, leading to dimensional inconsistencies and breakage, and require complex assemblies or separate drive systems for release, which can be costly and prone to leaks or entanglement.
Innovation Solution
A drive system utilizing a stripper plate with a core pin and core pin sleeve that moves axially and rotationally, driven by the axial motion of the stripper plate, allowing for the release of workpieces with undercuts without the need for non-axial core pin motion or separate release drives, and can be retrofitted to existing molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a core pin is used to form hollow workpieces, then hollow parts can be formed, but workpieces with undercuts cannot be stripped from the core pin
Solution Approach 1:
The core pin is made dynamically movable in a radial direction while maintaining axial positioning. The core pin can move radially outward to release workpieces with undercuts during the stripping phase, while returning to its axial position during molding. This dynamic capability allows the same core pin structure to handle both simple hollow workpieces and those with undercuts without requiring separate release mechanisms.
2Ease of operation
If complex assemblies or separate drive systems are used to release workpieces with undercuts, then workpiece release is achieved, but device complexity and risk of leaks increase
Solution Approach 1:
The release function for workpieces with undercuts is merged into the core pin structure itself through radial movability. Instead of adding separate drive systems, the core pin integrates both positioning and release functions through its ability to move radially, eliminating the need for additional complex assemblies and reducing leak risks associated with multiple hydraulic or pneumatic lines.
Solution Approach 2:
The core pin is designed with multi-functionality, serving both as a structural element to define the hollow cavity and as a release mechanism for workpieces with undercuts. By incorporating radial movability, the core pin performs multiple functions (molding and release) that previously required separate dedicated systems, thereby simplifying the overall apparatus.
3Ease of operation
If non-axial core pin motion is used to release workpieces, then workpiece stripping is enabled, but the core pin becomes difficult to control and prone to entanglement
Solution Approach 1:
The core pin motion is segmented into two independent directional components: axial positioning (for maintaining the hollow cavity shape) and radial movement (for releasing workpieces with undercuts). This segmentation allows each motion component to be controlled independently and reliably, preventing entanglement while enabling effective workpiece stripping. The axial and radial motions can be controlled by separate, simple mechanisms rather than complex coupled systems.
Data Source
AI summary
An apparatus and process for molding workpieces usable for consumer products. The workpieces may be injection molded with a cavity formed by a core pin and have an undercut, such as internal threads, in the cavity. The apparatus has a drive system with a stripper plate mounted for alternatingly forward and retracting axial movement. The stripper plate is axially driven and drives a stripper sleeve barrel cam and a core pin base barrel cam, each having respective cam followers. The respective motions of the cam followers are superimposed on a stripper sleeve insert, which drives a core pin sleeve. The core pin sleeve is subjected to responsive three dimensional motion, allowing an internally threaded workpiece to be unscrewed from the core pin sleeve. The system does not require separate drives for the core pin sleeve, a single stripper plate drive being sufficient.