Resin-Molded Flow Path Structure to Prevent Weld Defects
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Solution Overview
Problem
Existing two-color molding methods for resin-molded products face issues such as gaps forming between the mold frame and first resin members, leading to defects when molten second resin intrudes, and remelting of first resin members, which can hinder their desired functions.
Innovation Solution
A production method involving a mold frame with intersecting flow paths, where molten resin flows from a first flow path to a second flow path, reducing intrusion and remelting, with specific resin materials and welding configurations to form robust welded portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the first resin member accommodated in the mold frame shrinks, then a gap is formed between the mold frame and the first resin member, but this gap allows molten second resin to intrude and cause molding defects
Solution Approach 1:
A flow path structure is introduced as an intermediary element between the molten second resin and the first resin member. The flow path directs the molten resin away from the first resin member, preventing direct contact and intrusion into gaps, thus eliminating the molding defect while maintaining the gap-forming shrinkage characteristic
Solution Approach 2:
The mold frame is segmented into multiple functional regions: an accommodation portion for the first resin member and a flow path portion for guiding molten resin. This segmentation separates the functions of accommodating the first resin member and directing the second resin, preventing harmful interactions
2Strength
If the first resin member is brought into contact with the molten second resin, then welding between the first and second resin members is achieved, but the first resin member may remelt and cause molding defects
Solution Approach 1:
The flow path is designed with specific local characteristics: a width that is narrow in the first direction (limiting resin intrusion) and a length in the second direction that controls flow dynamics. This local quality optimization ensures adequate welding at the interface while preventing remelting defects in the first resin member
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 method effectively suppresses molding defects, ensuring the first resin members maintain their functions and enhances assembly integrity, particularly suitable for liquid discharge heads.
Implementation Method 1
contacting the molten resin and the first resin member to form a welded portion between the molten resin and the first resin member
Implementation Method 2
cooling the molten resin to form the second resin member
Data Source
AI summary
A production method for a resin-molded product includes preparing a mold frame including an accommodation portion accommodating the first resin member therein, a first flow path extending in a first direction, and a second flow path extending in a second direction intersecting the first direction and making the first flow path and the first resin member in the accommodation portion communicate with each other, injecting a molten resin forming the second resin member into the first flow path and causing the molten resin to flow from the first flow path to the second flow path, contacting the molten resin and the first resin member to form a welded portion between the molten resin and the first resin member, and cooling the molten resin to form the second resin member, wherein the welded portion is formed in the second flow path.