Ring Insert Molded Article Gate Mark Positioning
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Solution Overview
Problem
Conventional ring-shaped insert molded articles manufactured by disc gate-type injection molding require post-processing to remove foreign matter and burrs, and gate cutting can degrade the adhesive performance between the insert and plastic due to shearing loads and low strength at the joining surface.
Innovation Solution
The ring-shaped insert molded article is produced with a thermoset adhesive applied to the joining surface of a steel plate insert and plastic, where the plastic's inner diameter is larger than the insert's annular part, and the disc gate is positioned on the plastic's inner peripheral surface, separated from the annular part, preventing burrs and foreign matter from adhering and minimizing shearing loads during gate cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If gate cutting is conducted at the boundary surface between the support member and plastic magnet, then the gate mark is removed from the outer surface, but foreign matter remains on the insert and adhesive performance degrades due to shearing load
Solution Approach 1:
The invention extracts the gate cutting operation from the boundary surface between the support member and plastic magnet, relocating it to the inner peripheral surface of the plastic magnet. This separation removes the harmful effect of gate cutting from the adhesive joint area, eliminating foreign matter contamination and shearing load on the adhesive bond while still achieving gate mark removal from external surfaces.
2Ease of manufacture
If gate cutting is conducted at the boundary surface, then the gate mark is accessible for cutting, but additional post-processing is required to remove burrs from the inner diameter side
Solution Approach 1:
The invention inverts the conventional gate cutting approach by cutting the gate mark from the inner peripheral surface of the plastic magnet rather than from the outer boundary surface. This inversion allows the gate mark to be removed while preventing burrs from protruding to the inner diameter side, thereby eliminating the need for additional post-processing to remove burrs.
3Manufacturing precision
If the plastic inner diameter is made larger than the annular part inner diameter, then burrs do not protrude to the inner diameter side, but the gate mark position must be precisely controlled
Solution Approach 1:
The invention applies local quality by creating a localized dimensional difference where the plastic magnet's inner diameter is specifically made larger than the annular part's inner diameter only in the region where the gate mark will be formed. This localized dimensional variation prevents burr formation at the critical inner diameter side while maintaining precise gate position control through the defined radial separation distance.
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 configuration eliminates the need for additional post-processing to remove burrs and foreign matter, while maintaining adhesive performance by ensuring the gate mark resides on the plastic's inner surface, away from the insert, thus preventing degradation of the adhesive bond.
Implementation Method 1
a thermoset adhesive is applied to a joining surface of a ring-shaped insert to a plastic
Data Source
AI summary
A molded article 1 is configured such that an insert 2 is made of a steel plate and includes a cylindrical part 2A and an annular part 2B, a plastic 4 is annular in shape so as to be joined to the annular part 2B, inner diameter D1 of the plastic 4 is larger than inner diameter D2 of the annular part 2B so that no burrs at a gate mark E protrude to the inner diameter side of the molded article 1, the injection molding is conducted with a disc gate arranged on an inner peripheral surface F of the plastic 4 at a position separated from a surface of the annular part 2B, and the gate mark E resides on the inner peripheral surface F of the plastic 4 at a position separated from the surface of the annular part 2B.