Direct Injection Footwear with Supercritical-Foamed Sole Parts
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Solution Overview
Problem
Existing direct injection production (DIP) methods for footwear manufacturing are inefficient and costly, and cushioning elements like midsoles require additional adhesive joining, increasing production steps and material costs.
Innovation Solution
A method involving a direct injection process using premanufactured sole parts made via supercritical foaming, where injection material attaches the sole parts to the footwear upper, eliminating separate joining processes and allowing for lighter, softer sole structures with customizable properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional direct injection production is used, then production efficiency is improved, but manufacturing costs and energy consumption increase
Solution Approach 1:
The patent changes the physical-chemical parameters of the injection material by using supercritical fluids (supercritical CO2 or N2) instead of traditional polymers. This allows the material to be injected in a supercritical state and then expand and cure in-situ, reducing energy consumption while maintaining production efficiency. The supercritical state enables lower temperature and pressure processing compared to traditional injection molding.
Solution Approach 2:
The invention utilizes phase transitions of the injection material from supercritical fluid to solid foam structure. The material is injected in supercritical fluid form, then undergoes phase transition to expand and form the final foam structure within the mold cavity. This phase transition process reduces energy consumption while maintaining high production efficiency.
2Ease of operation
If cushioning elements are joined using adhesive, then comfort is improved, but production steps and material costs increase
Solution Approach 1:
The patent merges the cushioning element and sole construction into a single integrated structure manufactured by direct injection. The injection material forms both the cushioning layer and the bonding structure simultaneously, eliminating the need for separate adhesive joining steps. This integration maintains comfort properties while reducing production complexity.
Solution Approach 2:
The injection material serves multiple functions simultaneously: it provides cushioning, structural support, and bonding between components. The supercritical fluid-based material acts as both the cushioning element and the adhesive, eliminating the need for separate adhesive materials and joining processes.
3Manufacturing precision
If premanufactured sole parts are used, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by preforming the sole part geometry in the supercritical fluid injection mold before the material cures. The mold cavity is designed with precise geometry that defines the final sole part shape, and the supercritical fluid expands to fill this cavity, ensuring high manufacturing precision without requiring complex post-processing or assembly operations.
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 approach reduces manufacturing costs and energy use while producing footwear with lighter, softer, and customizable sole parts, enhancing user comfort and efficiency.
Implementation Method 1
a sole part that has been manufactured by a supercritical foaming process
Implementation Method 2
foamed by use of a foaming agent such as a super critical fluid comprising a supercritical nitrogen or a supercritical carbon dioxide
Implementation Method 3
direct injection of the sole to the upper, whereby injected material serves as a sole or part of a sole, when cured
Implementation Method 4
injected material configured for attaching said footwear upper to said at least one premanufactured sole part, said injection material upon curing providing an attaching sole part
Data Source
AI summary
A footwear manufactured by, and a method of manufacturing footwear by, a direct injection production. The method includes providing a direct injection mold, which is attachable to injection molding equipment and is configured for at least partly channeling injection material to a mold cavity. At least one premanufactured sole part of a sole structure is provided. The premanufactured sole part is positioned in relation to the direct injection mold. A footwear upper is positioned in relation to the direct injection mold. An injection material is injected into the mold cavity, and the mold cavity is at least partly formed by the direct injection mold. The injection material is configured for attaching the footwear upper to the at least one premanufactured sole part. The injection material, upon curing, provides an attaching sole part of the sole structure of the footwear. The at least one premanufactured sole part is a sole part that has been manufactured by a supercritical foaming process.