Footwear Injection Mould Inserts for Low-Cost Size Variants
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Solution Overview
Problem
Traditional footwear injection moulds made of metal are expensive, time-consuming, and require multiple moulds for different shoe sizes, making them impractical for limited edition or prototype lines, while 3D printed moulds face issues with thermal conductivity and structural integrity due to polymeric materials.
Innovation Solution
A footwear injection mould with a secondary injection mould featuring protrusions that increase structural strength and thermal conductivity, allowing for efficient and cost-effective production of footwear parts using a combination of primary and secondary injection moulds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional metal injection moulds are used, then manufacturing precision and structural integrity are improved, but manufacturing cost and production time increase significantly
Solution Approach 1:
The injection mould is divided into a primary injection mould and a secondary injection mould. The primary mould is a reusable metal mould that defines the overall cavity, while the secondary mould is a disposable 3D printed component that fits into the primary mould to create the final injection chamber. This segmentation allows the expensive metal primary mould to be reused many times while the inexpensive secondary moulds can be easily replaced or 3D printed as needed.
Solution Approach 2:
Instead of creating a complete metal mould from scratch for each shoe size and style, the patent uses a universal primary mould that can be filled with different secondary moulds. The secondary moulds are created using 3D printing technology, which is faster and more cost-effective than traditional metal mould fabrication. This copying approach allows rapid production of moulds for limited edition or prototype lines without the high cost of custom metal mould manufacturing.
2Ease of manufacture
If 3D printed polymeric moulds are used, then manufacturing cost decreases, but thermal conductivity and structural integrity worsen
Solution Approach 1:
The injection mould system combines two different materials: a metal primary injection mould that provides thermal conductivity and structural strength, and a polymeric secondary injection mould that provides the necessary geometric complexity and is cost-effective to 3D print. The metal primary mould acts as a heat transfer medium for the injected material, while the polymeric secondary mould defines the final cavity shape. This composite approach leverages the advantages of both materials while mitigating their individual disadvantages.
3Manufacturing precision
If multiple separate moulds are manufactured for different shoe sizes and orientations, then manufacturing precision for each size is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The primary injection mould is designed as a universal tool that can accommodate multiple different secondary injection moulds. A single primary mould can be used to produce various shoe sizes and styles by simply changing the secondary mould insert. This multi-functionality eliminates the need to manufacture separate complete moulds for each shoe size and orientation, significantly reducing the total number of moulds required while maintaining manufacturing precision for each specific application.
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 solution provides a cost-effective and efficient method for producing footwear parts with improved thermal conductivity and structural integrity, reducing production time and costs, especially for limited edition or prototype lines.
Implementation Method 1
the protrusion comprises an upper contacting surface for contacting an upper part of a footwear... the 3D printed mould closes around the upper of the sole in order to prevent the injected material from escaping the injection chamber of the mould
Implementation Method 2
a footwear injection mould for producing an article of footwear by direct injection moulding... a secondary injection mould defining at least part of an injection chamber for moulding a footwear part
Data Source
AI summary
A footwear injection mold includes a secondary injection mold defining at least part of an injection chamber. The injection chamber includes a proximal surface defining a part of a distal surface of a footwear part. The secondary injection mold includes a protrusion having an upper contacting surface, a proximal end, a primary surface faced away from the injection chamber, and a secondary surface facing the injection chamber. A normal of the upper contacting surface intersects a center point of the upper contacting surface. A protrusion plane is defined by the normal of the upper contacting surface along a width of the protrusion, and defines a boundary between a primary half and a secondary half of the protrusion, the primary half arranged between the protrusion plane and the primary surface, and the secondary half arranged between the protrusion plane and the secondary surface. A height of the proximal end of the protrusion is larger than the height of the upper contacting surface of the protrusion, relative to the normal of the upper contacting surface.