Footwear Midsole Lattice Molding Using a Removable Negative Mold

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Solution Overview

Problem

Conventional molding processes for shoe soles are limited by geometry, preventing the formation of midsoles with complex structures such as undercuts, apertures, and lattice structures that could enhance cushioning and customization.

Innovation Solution

Utilizing additive manufacturing to create a negative mold with complex geometric features, which is embedded in midsole material to form a lattice structure, allowing for customizable and improved cushioning properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional molding processes are used to form shoe soles, then the manufacturing process is simple and reliable, but the geometry is limited to simplistic forms without complex structures

Engineering Contradiction:

Improvegeometric complexityVSAvoidmolding process complexity

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The mold is divided into two distinct components: a reusable mold base and a removable negative mold. This segmentation allows the negative mold to be designed with complex geometric features (undercuts, overhangs, lattice structures) that would be impossible in a conventional single-piece mold, while the mold base remains simple and easy to manufacture. The negative mold can be removed after curing without damaging the complex midsole structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The negative mold acts as an intermediary element that enables complex midsole geometries. It is formed using additive manufacturing (which can create complex structures) and then used as a temporary form during the molding process. After the midsole material cures around it, the negative mold is removed, leaving the complex geometry in the final product without requiring the entire molding system to be complex.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Shape

If additive manufacturing is used to create the negative mold, then complex geometric features like lattice structures can be formed, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvelattice structure complexityVSAvoidmold manufacturing process

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

Complexity is localized only to the negative mold component, which is the only element requiring additive manufacturing. The mold base remains a simple, conventional component that can be manufactured using traditional methods. This localized application of advanced manufacturing minimizes the overall complexity increase while achieving the desired lattice structures in the midsole.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If conventional molding is used, then the manufacturing process is straightforward, but customization and cushioning optimization are limited

Engineering Contradiction:

Improvecustomization capabilityVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The negative mold is prepared in advance using additive manufacturing with the exact custom geometry required for each specific application. This preliminary creation of the negative mold with precise lattice structures, undercuts, and overhangs enables customization of cushioning properties before the actual midsole manufacturing begins. Different negative molds can be quickly produced for different customization requirements without retooling the entire molding system.

Inventive Principle:

Principle #10Preliminary action

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 complex geometric features like lattice structures, enhancing cushioning and customization, overcoming limitations of conventional molding processes.

Implementation Method 1

The mold may be formed by an additive manufacturing process (e.g., three-dimensional printing (3D printing))

Methodology Applied

Scientific Effect3D Printing: 3D Printing

Implementation Method 2

supplying a midsole material to the mold cavity of the mold base to form the midsole around a negative mold so that the negative mold is embedded within the midsole material

Methodology Applied

Scientific EffectEmbedding:

Data Source

PatentUS12570062B2Systems and methods for manufacturing a portion of an article of footwear from a mold

Publication Date: 2026.03.10 PUMA SE

AI summary

A method for manufacturing a midsole of an article of footwear includes arranging an insert into a mold cavity of a mold base. The insert including a region of solid volume that corresponds with an empty volume within the midsole. The method further includes supplying a midsole material to the mold cavity of the mold base to form the midsole around a negative mold so that the negative mold is embedded within the midsole material to form a midsole lattice structure within the midsole. The method further includes removing the negative mold with the midsole from the mold base. The method further includes removing the negative mold from the midsole.