Dual Density Footwear Midsole Manufacturing via Cold Injection
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Solution Overview
Problem
Conventional midsole manufacturing methods are limited in creating dual density midsoles, which restricts the ability to tailor performance characteristics across different regions of the midsole, affecting the footwear's ability to adapt to various activities.
Innovation Solution
A mold assembly and method that involves injecting materials of different densities into separate recesses, with one portion formed at a temperature below ambient and the second portion subjected to heat and pressure to bond the materials, allowing for the creation of midsoles with distinct density and hardness regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional single-material injection molding process is used to manufacture a midsole, then the manufacturing process is simple and efficient, but the midsole cannot achieve dual density regions with tailored performance characteristics
Solution Approach 1:
The manufacturing process is divided into two separate injection molding cycles. The first cycle forms a first portion of the midsole with first material having first density characteristics, and the second cycle forms a second portion with second material having second density characteristics. This segmentation enables dual density regions while maintaining injection molding as the core manufacturing method.
Solution Approach 2:
The first portion of the midsole is formed in advance during the first injection molding cycle, and then the second material is injected to form the second portion. This preliminary action allows the first material to be properly positioned and cured before adding the second material, ensuring proper bonding and density differentiation.
2Adaptability or versatility
If materials of different densities are used to create dual density midsoles, then the footwear can provide tailored performance characteristics, but the manufacturing process becomes more complex requiring multiple injection cycles
Solution Approach 1:
Two separate injection molding cycles are merged into a single continuous manufacturing process. The mold assembly remains in place, and the transition from forming the first portion to forming the second portion is seamless, eliminating the need for complete disassembly and reconfiguration between cycles.
Solution Approach 2:
The same mold assembly and injection system are used for both the first and second injection cycles. The mold members and injection apparatus perform multiple functions by forming different portions of the midsole with different materials, eliminating the need for separate specialized equipment.
3Adaptability or versatility
If a dual density midsole is manufactured using conventional methods, then it would require multiple separate manufacturing steps and assembly operations, but this increases production time and complexity
Solution Approach 1:
The first portion of the midsole is formed in advance during the first injection molding cycle, allowing proper positioning and initial curing. This preliminary action enables the second material to be injected directly onto a stable substrate, reducing overall production time compared to forming both portions separately and then assembling them.
Solution Approach 2:
The formation of both midsole portions is merged into a single continuous manufacturing process within the same mold assembly. The transition between forming the first and second portions occurs without removing the mold or transferring components, eliminating assembly time and reducing total production time.
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
Enables the production of midsoles with tailored performance characteristics by creating regions of varying densities and hardnesses, enhancing the footwear's ability to attenuate ground reaction forces and provide stability and comfort.
Implementation Method 1
injecting a first material into a first recess in the first mold member to form a first portion of a midsole while the first mold member is maintained at a temperature below an ambient temperature
Implementation Method 2
subjecting the second material and the first portion in the second mold assembly to heat and pressure to form a midsole
Implementation Method 3
subjecting the second material and the first portion in the second mold assembly to heat and pressure to form a midsole
Data Source
AI summary
A method of forming includes the steps of: placing a first mold member and a second mold member in contact with one another; injecting a first material into a first recess in the first mold member to form a first portion of a midsole while the first mold member is maintained at a temperature below an ambient temperature; removing the first portion of the midsole from the first recess; positioning the first portion of the midsole in the second recess in the third mold member of the second mold assembly; placing a second material into the second recess in contact with the first portion of the midsole; placing the third mold member and the fourth mold member in contact with one another; and subjecting the second material and the first portion in the second mold assembly to heat and pressure to form a midsole.