Mold Venting via Thin-Walled Slit Structure

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Solution Overview

Problem

The existing methods for manufacturing molds for rubber articles, particularly tires, face challenges in forming slit vents effectively, leading to issues like air bubbles and beard-like rubber formation, which affect the appearance and performance of the rubber article, and require high technology and increased production costs.

Innovation Solution

A method for manufacturing molds with a molding member that includes a thin-walled part where the slit vent is formed thinner than the thick-walled part, allowing the slit vent to penetrate and open to the molding surface, facilitating easy formation and reducing production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If through-holes (vent holes) are formed in the molding member, then air can be exhausted easily, but beard-like rubber (spew) is formed in the rubber article

Engineering Contradiction:
Improveease of forming ventilation mechanismVSAvoidbeard-like rubber formation
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention applies local quality by creating a slit vent with specific dimensional characteristics (width of 0.01 to 0.05 mm) in a localized region of the molding member. This narrow slit configuration allows air to escape while the restricted opening prevents rubber material from protruding into the vent, thereby eliminating beard-like rubber formation while maintaining effective ventilation functionality

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If slit vent is formed with regulated width and shape, then rubber can be restrained from protruding, but it requires high technology and increased production cost

Engineering Contradiction:
Improverubber protrusion preventionVSAvoiddifficulty of forming slit vent
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The invention applies parameter changes by specifying precise dimensional parameters for the slit vent (width of 0.01 to 0.05 mm) and creating a thin-walled part structure that facilitates slit formation. This approach transforms the difficult task of forming precise slits in thick material into a simpler process by providing a pre-thinned region where the slit can be formed more easily while maintaining the restrictive geometry needed to prevent rubber protrusion

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional metallic molds are used, then production can proceed, but slit vent can be formed only between piece metallic molds and not in the mold itself

Engineering Contradiction:
Improvemold production capabilityVSAvoidslit vent formation capability
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The invention applies segmentation by dividing the molding member into two distinct structural regions: a thin-walled part where the slit vent is formed, and a thick-walled part that provides structural support. This segmentation allows the slit vent to be formed directly within the molding member structure itself rather than relying on gaps between separate mold pieces, enabling integrated vent formation while maintaining overall mold structural integrity and productivity

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3403802B1Method for producing mold for rubber articles
Publication Date: 2020.04.08 BRIDGESTONE CORP
  • EP3403802B1 patent drawingFigure 1~2
  • EP3403802B1 patent drawingFigure 3~4C
  • EP3403802B1 patent drawingFigure 5~6C

AI summary

A slit vent is formed in a molding member of a mold for rubber article with ease. A molding member (30) of a mold (3A) is brought into contact with a rubber article through a molding surface (5A) to mold the rubber article. The molding member (30) having a thin-walled part (33) is formed by making a part in which a slit vent (34) of the molding member (30) is to be formed, thinner than other part of the molding member (30). The slit vent (34) is formed in the thin-walled part (33) of the molding member (30). The slit vent (34) penetrates the thin-walled part (33) and opens to the molding surface (5A).