Resin Molded Cable Bolt Hole Crack Prevention
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Solution Overview
Problem
Conventional methods of manufacturing cables with resin molded bodies often result in cracks around bolt holes due to weld formation when tightening bolts, as the resin flows and meets at these points during the molding process.
Innovation Solution
The method involves molding the resin molded body using a mold with a specific outlet behind the flange-molding portion to drain resin around the bolt hole, preventing weld formation by ensuring resin flowability and using multiple resin inlets to ensure complete coverage and adhesion without residual strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resin is injected from a position facing the covering at the base end portion of the main body, then the covering is softened and adhered to the resin molded body providing waterproof properties, but weld lines are formed around the bolt hole which cause cracks when tightening the bolt
Solution Approach 1:
The resin injection system is segmented into multiple injection ports positioned at different locations. The first injection port is positioned to face the covering for waterproof adhesion, while the second injection port is positioned to inject resin toward the flange, preventing weld line formation around the bolt hole. This segmentation allows independent control of resin flow paths to achieve both waterproofing and structural integrity.
Solution Approach 2:
The injection system transitions from a single-point injection to multi-point injection in different spatial dimensions. The first injection port is positioned at the base end portion facing the covering, while the second injection port is positioned at the top end portion facing opposite to the cable, creating three-dimensional resin flow control that prevents weld lines while ensuring comprehensive coverage and adhesion.
2Manufacturing precision
If resin is injected to ensure complete coverage and adhesion, then waterproof properties are improved, but weld lines may form around the bolt hole causing potential cracks
Solution Approach 1:
The resin injection process is segmented into two separate injection ports with distinct functions. The first injection port ensures complete coverage and adhesion by injecting resin toward the covering, while the second injection port prevents weld line formation by injecting resin toward the flange from a different direction, thereby maintaining both adhesion quality and structural reliability.
Solution Approach 2:
Different regions of the mold cavity receive resin from different injection ports with optimized flow directions. The region near the covering receives resin from the first injection port for optimal adhesion, while the region near the flange and bolt hole receives resin from the second injection port to prevent weld lines, achieving local quality optimization for each critical area.
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 approach effectively prevents crack formation around bolt holes during tightening, enhancing the durability and reliability of the cable with resin molded bodies by controlling resin flow and adhesion.
Implementation Method 1
the injected resin flows around both sides of the bolt hole 47 at the flange 46 as indicated by arrows in FIGS. 4B and 4C and a weld (weld line) 50 may be formed at a position where the two resin flows meet again
Implementation Method 2
A high-temperature resin injected from the resin inlet 49 toward the covering 42a of the cable 42 softens the covering 42a which is then adhered to the resin molded body 44
Data Source
AI summary
A method of manufacturing a cable with resin molded body, wherein the cable with resin molded body includes a cable and a resin molded body formed by resin molding, wherein the resin molded body includes a main body to cover the tip portion of the cable and a flange integrally molded with the main body, and wherein the flange includes a bolt hole through which a bolt is inserted so as to fix the flange to the attachment object. The method includes molding the resin molded body by injecting a resin into a mold, the mold including a main body-molding portion for molding the main body, a flange-molding portion for molding the flange and an outlet formed behind the flange-molding portion in relation to the main body-molding portion, and draining the resin through the outlet during the molding of the resin molded body.