Sliding-Pin Insert Molding Die for Complex-Shape Sealing

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Solution Overview

Problem

Existing methods struggle to expose complex-shaped insert members, such as connectors, to the outside of a resin molded body while ensuring adequate sealing, often requiring additional sealing steps that can lead to moisture ingress and connection failures.

Innovation Solution

A method involving a sliding pin that synchronizes with mold clamping to form a sealing surface around the exposed portion, allowing the insert member to be embedded and sealed within the resin molded body, using a housing portion with divided pieces that deform to accommodate complex shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a through-hole is provided in the resin molded body after insert molding for electrical connection, then the insert member can be electrically connected, but additional sealing steps are required which increase manufacturing time and risk of moisture ingress

Engineering Contradiction:
Improvesealing reliabilityVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The molding space is designed in advance with a specific configuration that includes a third surface formed by the sliding pin at the boundary between the embedded portion and exposed portion. This preliminary design allows the resin to automatically seal the embedded portion during the molding process itself, eliminating the need for subsequent sealing steps while ensuring reliable sealing from the outset

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sealing function is merged with the molding process itself. The third surface formed by the sliding pin creates a sealing interface that is formed simultaneously with the resin molded body, combining the sealing action with the primary molding operation rather than requiring separate sealing steps

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If conventional insert molding is used, then simple insert members can be exposed, but complex-shaped insert members such as connectors cannot be easily exposed

Engineering Contradiction:
Improveadaptability to complex shapesVSAvoidmanufacturing simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The sliding pin is designed to be movable relative to the mold cavity, allowing it to dynamically adjust its position and form the third surface at the boundary between the embedded and exposed portions. This dynamic capability enables the mold to accommodate complex-shaped insert members while maintaining the ability to expose specific portions and ensure proper sealing

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The insert member is segmented into distinct functional portions: the embedded portion that is sealed within the resin molded body, the exposed portion that extends outward for electrical connection, and the boundary between them. The sliding pin creates a third surface that segments the molding space to properly contain and seal the embedded portion while allowing the exposed portion to be accessed

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4585388A1Method for producing resin molded article, resin molded article, and die for insert molding
Publication Date: 2025.07.16 NISSHA PRINTING CO LTD
  • EP4585388A1 patent drawingFigure 1
  • EP4585388A1 patent drawingFigure 2~3
  • EP4585388A1 patent drawingFigure 4

AI summary

Provided is an insert molding method in which an embedded portion formed continuously to an exposed portion is sufficiently supported by resin of a resin molded body itself and the embedded portion is easily sufficiently sealed. A sliding pin 130 is slid in synchronization with clamping of a first mold 110 and a second mold 120, and is deformed so as to wrap an exposed portion 50 with an embedded portion 40 of an insert member exposed to a molding space. The sliding pin 130 forms a third surface of a wall surface of the molding space at a boundary between the embedded portion 40 and the exposed portion 50. The embedded portion 40 is located in molten resin, and the molten resin is injected until the molten resin comes into contact with the third surface and is solidified. The sliding pin 130 is slid and is deformed so as to release the exposed portion 50 wrapped with the sliding pin 130.