Injection Mold Reservoir Layout for Stronger Fiber-Reinforced Welds
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Solution Overview
Problem
Conventional injection molding techniques fail to adequately enhance the strength of weld portions in resin products, which are typically weaker than other parts of the molded article.
Innovation Solution
An injection mold with a unique configuration that includes a gate and cavity system, where molten resin containing reinforcing fibers is injected, and a resin reservoir that modifies the resin flow pattern to create a stronger weld portion by altering the distance between the resin reservoir and cavity centerlines, resulting in a more complex and three-dimensional resin flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional injection molding is used, then the manufacturing process is simple, but the weld portion strength is insufficient
Solution Approach 1:
The cavity is divided into multiple cavities arranged in an array, with each cavity forming a separate molded article. Multiple gates are provided to inject molten resin into different cavities, allowing independent control of resin flow paths. This segmentation enables optimization of each weld portion independently while maintaining overall manufacturing efficiency.
Solution Approach 2:
The mold structure is designed with different characteristics at different locations: the cavity has a specific depth, the resin reservoir has a greater depth than the cavity, and the bottom surface of the resin reservoir is positioned at a specific depth. These local variations in depth and structure create controlled resin flow patterns that concentrate reinforcing fibers at weld portions, improving local strength without requiring complete redesign of the entire mold.
2Strength
If resin flow is kept simple, then the manufacturing process is efficient, but the weld portion strength cannot be sufficiently improved
Solution Approach 1:
The resin reservoir is designed to store molten resin before injection into the cavity. The bottom surface of the resin reservoir is positioned at a specific depth to control the resin flow path in advance. This preliminary positioning ensures that reinforcing fibers are oriented favorably at weld portions before the actual molding occurs, improving weld strength without adding post-processing steps that would reduce productivity.
Solution Approach 2:
The invention introduces a depth dimension variation by making the resin reservoir deeper than the cavity itself. This vertical dimensionality change allows control over resin flow paths and fiber orientation in three dimensions, creating complex flow patterns that improve weld strength while maintaining a relatively simple overall mold structure that doesn't significantly impact cycling time.
Data Source
AI summary
An injection mold including a gate and a cavity, where a weld portion is formed inside the cavity by injecting molten resin containing reinforcing fibers from the gate into the cavity, the injection mold has a resin reservoir open to the cavity, and in a first cross section along an opening end surface 110S of the resin reservoir 110 to the cavity, a distance CLD between a width center line CL11 of the resin reservoir and a width center line of the cavity, which is measured along a perpendicular line n12 of the width center line CL12 of the cavity, changes at least in part along the width center line of the cavity.