CVJ Boot Die with Radial-Axial Molds for Undercut Release
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Solution Overview
Problem
Molding of CVJ boots with bellows portions that create undercuts on the inner peripheral surface is challenging due to difficulties in releasing the molded article from the die, and existing methods like blow molding and injection blow molding face issues with accuracy and prolonged cycles.
Innovation Solution
A die comprising a central core and divisional molds that allow for radial and axial movement, enabling the release of the molded body by retracting the central core and moving divisional molds to prevent interference and allow for greater movement, facilitating injection molding of CVJ boots with complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If blow molding is used to mold the bellows portion, then the molded article can be released from the die, but the molding precision and wall thickness control deteriorate
Solution Approach 1:
The core mold is designed with movable segments that can dynamically change their position during the molding process. The segments move radially outward to create release space for the bellows portion, enabling injection molding without sacrificing ease of release or molding precision
Solution Approach 2:
The core mold is divided into multiple segments that can move independently. This segmentation allows specific portions of the core to move radially outward to eliminate undercuts, while other segments remain stationary to maintain molding precision for critical features
2Ease of operation
If injection blow molding is used to mold the bellows portion, then the molded article can be released from the die, but the facilities become large-sized and the molding cycle is prolonged
Solution Approach 1:
The invention merges the injection molding and blow molding processes into a single integrated injection molding operation. The movable core segments enable the bellows portion to be molded directly by injection molding, eliminating the need for separate blow molding equipment and reducing the overall molding cycle time
Solution Approach 2:
The dynamic movement of core segments during injection molding eliminates the need for multi-step processes. The segments move radially outward during mold opening to facilitate release, allowing the entire process to be completed in one injection molding cycle rather than requiring separate injection and blow molding steps
3Ease of operation
If a foldable core with inner and outer segments is used, then the molded article can be released from the die, but the segments interfere with each other promptly after retraction starts
Solution Approach 1:
The core mold is segmented into multiple independent movable segments arranged radially. Each segment can move outward independently without interfering with others, as they move in different radial directions from the central axis, eliminating the interference problem while maintaining ease of release
Solution Approach 2:
The segments move in the radial dimension rather than folding in the axial dimension. This dimensional change allows segments to move outward perpendicular to the injection direction without interfering with each other, simplifying the core structure while maintaining release capability
4Shape
If the bellows portion makes an undercut with respect to the molding face, then the complex geometry can be formed, but the molded article cannot be removed from the core mold
Solution Approach 1:
The core mold segments move dynamically during the molding cycle. During injection, the segments are in the retracted position to form the complex bellows geometry with undercuts. During mold opening, the segments move radially outward to eliminate undercuts and enable easy removal of the molded article
Solution Approach 2:
The core is divided into segments that can move independently to different positions. This allows the molding face to present different configurations: a retracted configuration during injection to form complex geometries, and an extended configuration during removal to eliminate undercuts
Data Source
AI summary
A die for manufacturing CVJ boot by injection molding includes a central core, and a plurality of divisional molds for molding an inner peripheral surface of the CVJ boot, respectively. The divisional molds move diametrically toward the central core. Moreover, the divisional molds not only approach one another diametrically, but also get away from each other axially.