Injection Molding Apparatus Peripheral Space for Bubble-Free Filling
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Solution Overview
Problem
In injection molding, it is challenging to homogeneously fill narrow gaps between mold substrates with high viscosity compositions, often resulting in air bubble mixing issues in the molded product.
Innovation Solution
The introduction of a space around the periphery of the gap between mold substrates, with a width greater than the gap, allows for the injection and filling of the composition, ensuring uniform filling and reducing air bubble incorporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the gap width between mold substrates is reduced to achieve thinner molded products, then the product thickness is improved, but the composition cannot be homogeneously filled and air bubbles mix into the molded product
Solution Approach 1:
The injection path is segmented into two stages: first injecting into the space (peripheral region) and then filling the gap (central region). This segmentation allows the high viscosity composition to be properly distributed before final filling, preventing air bubble incorporation while achieving thin gap dimensions.
Solution Approach 2:
The space is pre-filled with composition before the gap is filled. This preliminary action ensures that the composition is ready and properly positioned to flow into the narrow gap without trapping air bubbles, solving the filling homogeneity problem in thin-gap molding.
2Manufacturing precision
If the composition viscosity is increased to improve material properties, then the molded product quality is improved, but the composition cannot be homogeneously filled in narrow gaps
Solution Approach 1:
The injection process is divided into two sequential steps: injecting into the space first, then filling the gap. This allows high viscosity composition to be properly handled and distributed in the peripheral space before entering the narrow gap, maintaining material quality while improving fillability.
Solution Approach 2:
The space acts as an intermediary region between the injection portion and the narrow gap. High viscosity composition is first injected into this intermediate space, allowing it to adjust and flow smoothly before entering the constrained gap, thus facilitating homogeneous filling despite high viscosity.
3Manufacturing precision
If the gap width is reduced to achieve precise molding, then the molding precision is improved, but air bubbles mix into the molded product
Solution Approach 1:
The space is pre-filled with composition before gap filling, creating a cushion of material that prevents air from being trapped during the subsequent gap filling process. This preliminary action eliminates air bubble incorporation while maintaining precise gap dimensions.
Solution Approach 2:
The space, which initially appears as extra material that might cause defects, is actually converted into a beneficial feature that prevents air bubble incorporation. The space allows proper composition distribution and acts as an air escape path, transforming a potential harm into a benefit for achieving bubble-free precise molding.
Data Source
AI summary
An injection molding apparatus includes a substantially circular first substrate, a substantially circular second substrate disposed to face a surface of the first substrate, a fixing member which fixes a peripheral end portion of the first substrate and a peripheral end portion of the second substrate, and an injection portion which is provided in the fixing member and from which a composition is injected into a gap between the first substrate and the second substrate, in which a space connecting with the injection portion and the gap is provided in at least a part of a periphery of the gap, and a width of the space in a thickness direction is larger than a width of the gap in the thickness direction.