Sole Assembly Bonding Multiple Preforms

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Solution Overview

Problem

Conventional methods for manufacturing sole assemblies in athletic footwear often result in color bleeding between differently colored portions, compromising the aesthetic appeal due to the use of polymer foam materials like EVA in molding processes.

Innovation Solution

A method involving multiple mold assemblies to form preforms of different colors, which are then combined and bonded in a single step to minimize color bleeding, using EVA with specific formulations and surface irregularities to enhance both performance and aesthetics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple colored portions are formed in a single mold assembly, then productivity is improved, but color bleeding occurs between portions

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidcolor boundary definition

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The sole assembly is divided into multiple preforms, each formed separately in its own mold assembly. This segmentation prevents color bleeding by isolating different colored portions during formation, while maintaining manufacturing efficiency through subsequent consolidation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple preforms with different colors are combined and bonded into a single sole assembly. This merging approach allows each preform to maintain its color integrity while achieving the final multi-colored product in one consolidation step

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If polymer foam material is used for midsole, then cushioning and comfort are improved, but color bleeding occurs during molding

Engineering Contradiction:

Improvecushioning performanceVSAvoidcolor boundary definition

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The polymer foam material is segmented into separate preforms before final assembly. Each preform is formed with its specific color and cushioning properties isolated, preventing color bleeding while maintaining the overall cushioning performance of the sole assembly

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the sole assembly have different local qualities - each preform provides specific cushioning characteristics tailored to its location, while the separation of preforms prevents color bleeding between adjacent regions

Inventive Principle:

Principle #3Local quality

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

The method effectively reduces color bleeding, enhancing the aesthetic appeal of the sole assembly while allowing for varied physical properties and performance characteristics across different components, improving support, cushioning, and traction.

Implementation Method 1

A mold assembly is then positioned over the preforms and heat is applied to the preforms within the mold assembly for a predetermined time period so as to bond the preforms together

Methodology Applied

Scientific EffectHeat: Heating

Data Source

PatentEP3476235B1Sole assembly formed of multiple preforms

Publication Date: 2022.03.09 NIKE INNOVATE CV

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AI summary

A method of forming a sole assembly includes positioning a plurality of preforms having different colors together to form a sole assembly preform and placing the sole assembly preform in a recess in a first portion of a mold assembly. The sole assembly preform is subjected to heat for a predetermined amount of time such that the plurality of preforms bond to one another to form a sole assembly.