Inflatable-Bladder Thermoforming for Lightweight Textile Sole Structures
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Solution Overview
Problem
Conventional footwear manufacturing methods are complex, energy-intensive, and material-consuming, often resulting in scraps, and the sole structures lack flexibility in material choice, weight, and customization, particularly in sports footwear.
Innovation Solution
A method involving a thermo-compression process using an inflatable bladder to mold a fully or partly hot-meltable textile sole element within a mold structure, allowing for localized material and aesthetic customization while reducing manufacturing steps and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple textile booties are superimposed and thermoformed to create a three-dimensional upper, then the upper can be formed directly in 3D without sewing, but the footwear becomes too heavy for sports activities
Solution Approach 1:
The patent extracts only the necessary textile layers required for the upper structure, eliminating redundant layers. By using a single textile bootie with strategically placed hot-meltable yarns rather than superimposing multiple booties, the invention reduces material quantity while maintaining the 3D shaping capability through thermoforming.
Solution Approach 2:
The patent applies hot-meltable yarns selectively at specific locations within the textile bootie where structural reinforcement is needed. This localized application allows the yarns to be melted and repositioned only in areas requiring enhanced strength or shape retention, rather than throughout the entire structure, thereby reducing overall material weight.
2Shape
If an outsole is thermoformed between two flexible textile booties, then the upper can be shaped in 3D, but the positioning reproducibility deteriorates and scrap rate increases
Solution Approach 1:
The patent segments the footwear into distinct components: a flexible textile upper bootie and a separate rigid outsole. This segmentation allows each component to be manufactured and shaped independently with optimal precision, then assembled together. The outsole can be precisely molded without the constraints of accommodating flexible textile layers, improving positioning reproducibility.
Solution Approach 2:
The patent introduces an intermediary assembly step where the textile bootie is thermoformed over a mold that includes the outsole. This intermediary mold structure provides a rigid reference framework that ensures precise positioning and reproducibility during the thermoforming process, while still allowing the final assembly to achieve the desired 3D shape.
3Ease of manufacture
If conventional injection methods are used to manufacture soles, then the manufacturing process is established, but the number of polymer materials and colors is limited to two for cost reasons
Solution Approach 1:
The patent changes the fundamental parameter of material application from conventional injection molding to thermoforming of textile materials. This parameter change enables the use of various textile materials (cotton, polyester, nylon, wool) and color combinations without being constrained by the limited palette of conventional injection molding, while maintaining manufacturing stability through the established thermoforming process.
Solution Approach 2:
The patent employs composite material construction by combining textile materials with hot-meltable yarns in a layered structure. This composite approach allows for greater material diversity and customization options, as different textile materials and colors can be integrated into the upper bootie and sole elements, exceeding the limitations of single-material injection molding.
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 enables the production of lightweight, customizable sole structures with improved mechanical properties and aesthetic options, reducing material waste and manufacturing complexity.
Implementation Method 1
inflating the inflatable bladder to press, directly or indirectly, the external face of the textile sole element against the sole cavity
Implementation Method 2
heating the textile sole element in order to melt the at least partly hot-meltable yarn(s)
Data Source
AI summary
A method for manufacturing a sole structure involving supplying at least one textile sole element having an outer face, including one or more at least partially hot-meltable filament(s); placing the at least one textile sole element in a mould structure including a sole cavity intended to come into contact with the outer face of the textile sole element; placing an inflatable bladder in the mould structure and inflating the inflatable bladder to press the outer face of the textile sole element either directly or indirectly firmly against the sole cavity and heating the textile sole element to melt the at least partially hot-meltable filament(s) and mould the sole cavity onto the outer face of the sole element; obtaining a sole structure including a thermally compressed textile sole element.