Window Edge Molding Joint Structure to Prevent Denting and Burrs
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Solution Overview
Problem
The existing window edge molding technologies face issues with low rigidity of the covering portion, leading to denting and burr formation during injection molding of the end covering portion, which affects the quality and appearance of the molded article.
Innovation Solution
A long molded article design with a main body portion and an end covering portion, where the joint portion between them has a thicker inner end portion and a thinner outer end portion, made of elastic polymer material, to prevent burr formation and maintain the exposed surface's integrity during injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the covering portion is formed with a hollow portion behind it to reduce material usage, then the weight and material consumption are reduced, but the rigidity of the covering portion becomes insufficient causing denting during injection molding
Solution Approach 1:
The joint portion is designed with non-uniform thickness, being thicker at the inner end portion (near the hollow portion) and thinner at the outer end portion. This local variation in thickness provides enhanced rigidity precisely where needed to prevent denting during injection molding, while maintaining material efficiency in other areas.
2Ease of manufacture
If the end covering portion is injection molded on the outer surface of the covering portion, then the end covering portion can be integrated with the main body, but the injection pressure causes denting of the outer surface and generation of burrs
Solution Approach 1:
The joint portion's thickness is locally optimized to be greater at the inner end portion, creating a reinforced zone that specifically addresses the denting problem during injection molding of the end covering portion while allowing integration to proceed.
Solution Approach 2:
The thicker inner end portion of the joint portion is designed in advance to counteract the denting effect that will occur during subsequent injection molding of the end covering portion. This preliminary structural reinforcement prevents the harmful effect before it manifests.
3Ease of manufacture
If the joint portion has uniform thickness, then the manufacturing process is simpler, but the rigidity is insufficient to prevent denting and burr formation at the joint region
Solution Approach 1:
Instead of uniform thickness, the joint portion employs variable thickness with the inner end portion being thicker. This provides the necessary rigidity to prevent denting and burr formation while keeping the manufacturing process relatively simple through injection molding.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the rigidity of the joint portion, reducing the likelihood of denting and burr formation, thereby improving the quality and appearance of the molded article by preventing burrs from protruding towards the exposed surface.
Implementation Method 1
when the end covering portion is formed by injection molding on an outer surface (design surface) of the covering portion of the molding body, the outer surface of the covering portion may be dented (that is, caved in) by the injection pressure
Implementation Method 2
If the molten polymer material forming the end covering portion enters a dent portion of the covering portion that is not covered by the end covering portion and solidifies as it is, burrs are generated by the solidified polymer material
Data Source
AI summary
A long molded article includes: a main body portion and an end covering portion. A wall portion of the main body portion includes an outer surface defining in part an exposed surface and an inner wall surface defining a hollow portion formed therein. The end covering portion is integrated with and covers a joint portion provided in a part of the wall portion defining one end portion of the hollow portion or a vicinity thereof. A first thickness between the outer surface and the inner wall surface in a first portion of the joint portion in a vicinity of an inner end portion is set to be thicker than a second thickness in a second portion of the joint portion on an outer end portion side relative to the first portion.