Blowing Mold Striker Plate Protrusions for Preform Alignment
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Solution Overview
Problem
Existing blow molding processes face issues with preform rotation and decentering, which can lead to misalignment between the preform and mold axes, particularly when using conventional preforms without specific projections above the neck ring.
Innovation Solution
A blowing mold design featuring protrusions on the striker plate that contact the preform below the neck ring to prevent rotation and ensure alignment, allowing the use of conventional preforms without additional orientation features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional preforms without specific projections are used, then the preform structure is simple and manufacturing is easier, but the preform rotates and decenters in the mold during closing
Solution Approach 1:
The striker plate incorporates asymmetric protrusions that break the rotational symmetry of the preform-mold interface. These protrusions are positioned at specific angular locations to prevent the preform from rotating during mold closing, thereby achieving precise alignment without modifying the preform itself.
Solution Approach 2:
The protrusions on the striker plate act as intermediary elements between the preform and the mold closing force. These protrusions engage with the preform's neck ring area to transmit alignment constraints, preventing rotation and decentering while allowing the preform to remain otherwise unchanged.
2Manufacturing precision
If driving elements are added to prevent preform rotation, then preform alignment is improved, but the mold structure becomes more complex
Solution Approach 1:
The alignment function is segmented into discrete protrusions on the striker plate rather than requiring a complex continuous mechanism. Each protrusion is a simple geometric feature that independently contributes to preventing rotation, making the overall mold structure easier to manufacture while achieving the desired precision.
Solution Approach 2:
Instead of adding complex driving elements that actively control preform orientation, the invention inverts the approach by using simple protrusions that passively prevent rotation through geometric constraint. The protrusions engage with the preform's neck ring area to transmit alignment constraints, eliminating the need for active control mechanisms.
3Adaptability or versatility
If the preform axis is allowed to differ from the mold axis, then preform positioning is more flexible, but the molding precision and container quality deteriorate
Solution Approach 1:
The asymmetric protrusions on the striker plate create specific engagement points that guide the preform into correct alignment with the mold axis. This asymmetric constraint ensures that even if the preform is initially positioned with some misalignment, the protrusions force the preform axis to coincide with the mold axis during closing, achieving both flexibility in initial positioning and precision in final alignment.
Data Source
AI summary
A blowing mold (1) for molding a container (90), in particular a plastic bottle, by blow molding a preform (9) having a neck (93) and a neck ring (92), the blowing mold (1) being adapted to be opened and closed, and comprising at least two parts (25, 26) which, when the blowing mold (1) is closed, form a support (2), or striker plate, adapted to abut against the neck ring (92) of the preform (9); wherein a surface (20) of said support (2) is provided with one or more protrusions (21) adapted to come into contact with the portion (931) of the preform (9) below the neck ring (92), in particular to prevent a rotation thereof.