Footwear Tread Assembly Injection Molding Process

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Solution Overview

Problem

Current methods for manufacturing tread assemblies for footwear outsoles are inefficient and lack flexibility in material composition, requiring multiple steps and limited variation.

Innovation Solution

A method involving a central mold with injection and lug cavities, where a rubber block is compressed to flow viscously into lug cavities attached to a matrix lining, allowing for different materials and colors to be used simultaneously, and enabling the creation of complex tread designs with reduced steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional multi-step methods are used to manufacture tread assemblies, then manufacturing precision can be maintained, but production efficiency decreases and manufacturing time increases

Engineering Contradiction:
Improveproduction efficiencyVSAvoidmanufacturing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent combines multiple manufacturing steps into a single injection molding operation. The mold includes integrated components (matrix lining, tread elements, reinforcement elements) that are all formed simultaneously from injected material, eliminating sequential assembly steps and reducing production time while maintaining precision

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The matrix lining is pre-placed in the mold cavity before injection, and the mold design pre-establishes the positions of all features. This preliminary preparation allows the injection step to directly form the complete tread assembly without requiring subsequent assembly operations, improving productivity

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If traditional methods with separate steps are used, then material composition can be controlled, but manufacturing complexity increases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidprocess complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges multiple manufacturing operations into a single injection molding process. The mold design integrates matrix lining, tread elements, and reinforcement features into one cavity system, allowing all components to be formed in one step, thereby simplifying the manufacturing process while maintaining material control

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The injection molding process serves multiple functions simultaneously: it forms the matrix lining, creates tread elements with specific geometries, incorporates reinforcement elements, and achieves proper material distribution. This multi-functionality reduces the number of separate manufacturing steps required

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If traditional methods are used, then material flexibility is limited, but manufacturing reliability can be maintained

Engineering Contradiction:
Improvematerial composition flexibilityVSAvoidmanufacturing reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent enables material flexibility by allowing different rubber compounds, colors, and material properties to be incorporated into the injection process. The mold design accommodates various material compositions while maintaining consistent manufacturing outcomes through controlled injection parameters and proper mold cooling systems

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes composite material approaches by combining different rubber compounds, fillers, and reinforcement elements within the same tread assembly. The injection molding process can introduce multiple materials in sequence or simultaneously, creating composite structures with tailored properties while maintaining manufacturing reliability through process control

Inventive Principle:
Principle #40Composite materials

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 method enhances production efficiency, allows for varied material compositions and colors, and simplifies the process of creating complex tread designs, improving the flexibility and aesthetic options for footwear outsoles.

Implementation Method 1

compressing the rubber block between the molding press and the second side of the central mold so that the rubber block becomes viscous

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

the resulting viscous rubber material flows into at least one lug cavity

Methodology Applied
Scientific EffectViscous flow:

Data Source

PatentEP2745723B1Method for making a tread assembly
Publication Date: 2020.03.18 NIKE INNOVATE CV
  • EP2745723B1 patent drawingFigure 1~2
  • EP2745723B1 patent drawingFigure 3~4
  • EP2745723B1 patent drawingFigure 5

AI summary

A method of making an article of footwear, comprises the steps of: placing a matrix lining between a molding base and a second side of a central mold; placing a rubber block between a molding press and a first side of the central mold; and compressing the rubber block between the molding press and the first side of the central mold so that the rubber block becomes viscous and the resulting viscous rubber material flows into at least one lug cavity disposed on the second side of the central mold; wherein the lug cavity is disposed proximate the matrix lining; and wherein the viscous rubber material attaches to the matrix lining.