Resin Joint Flow Path Structure for Low Pressure Loss Molding
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Solution Overview
Problem
The existing resin joints with curved flow paths face issues during injection molding, where the core pin gets stuck or the inner surface is damaged due to the curvature, leading to difficulties in core pin extraction and potential fluid pressure loss.
Innovation Solution
A resin joint design featuring a joint body with a curved inner surface and a press-fit sleeve system, including a union nut for fixing the tube, which reduces pressure loss and allows for smooth core pin removal by using a groove portion for press-fitting the sleeve, ensuring fluid sealability and minimizing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a curved flow path with great curvature radius is formed to reduce pressure loss, then fluid flow smoothness is improved, but the core pin cannot be pulled out during injection molding
Solution Approach 1:
The curved section of the core pin is segmented from the straight sections by introducing tapered sections at both ends of the curved portion. This segmentation allows the core pin to be extracted in stages, where the tapered sections facilitate easy removal from the straight portions of the mold cavity while maintaining the curved flow path geometry.
Solution Approach 2:
The core pin employs a composite structure combining curved and straight sections with tapered transitions. This composite design integrates the benefits of curved geometry for smooth fluid flow with straight sections for easy mold extraction, resolving the contradiction between flow path quality and manufacturability.
2Ease of manufacture
If the curvature radius of the core pin is reduced to facilitate extraction, then core pin removal becomes easier, but the inner peripheral surface of the straight section is damaged
Solution Approach 1:
Tapered sections are preliminarily introduced at the ends of the curved portion to create a gradual transition zone. This preliminary design feature prevents sudden contact between the core pin and the mold cavity walls during extraction, eliminating surface damage while maintaining extraction feasibility.
Solution Approach 2:
The core pin geometry parameters are changed by introducing tapered sections with specific angles at the ends of the curved portion. This parameter modification creates a gradient in the contact area during extraction, reducing stress concentration and preventing surface damage to the straight sections.
3Ease of manufacture
If a straight section is added to the core pin for easier extraction, then manufacturability is improved, but the flow path curvature is compromised
Solution Approach 1:
The straight sections are nested within the overall core pin structure, containing the curved flow path section between them. This nested arrangement allows the curved portion to maintain its geometry for smooth fluid flow while the outer straight sections provide the necessary extraction functionality.
Data Source
AI summary
A resin joint includes a joint body having a flow path, sleeves, and union nuts that fix tubes to the joint body. The joint body has a body portion with a curved inner peripheral surface and a straight portion protruding from an end portion of the body portion. The straight portion has outer and inner cylindrical portions radially arranged inside the outer cylindrical portion. An end portion of the inner cylindrical portion is positioned closer to the body portion than is an end portion of the outer cylindrical portion. A groove portion extending parallel with the outer and inner cylindrical portions in an axial direction is formed between an inner peripheral surface of the outer cylindrical portion and an outer peripheral surface of the inner cylindrical portion. The tube is fixed to the joint body such that a press-fit portion of the sleeve is press-fitted in the groove portion.