Expanded TPU Powders for Lightweight 3D Molding
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Solution Overview
Problem
Current 3D printing technologies using thermoplastic polyurethane powders face challenges in achieving low-density, high-rebound resilience, and good mechanical properties, particularly in expanding 3D printed parts for end-use applications like automotive and footwear industries.
Innovation Solution
Development of thermoplastic polyurethane (TPU) powders derived from expanded TPU or molding parts, with specific particle size and bulk density ranges, combined with auxiliary agents like fillers and pigments, for use in 3D molding processes such as selective laser sintering and multi jet fusion, to produce lightweight yet robust 3D products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermoplastic polyurethane powders are used for 3D printing, then the mechanical properties and rebound resilience are improved, but the density is high and the weight is increased
Solution Approach 1:
The patent applies porous materials by using expanded TPU pellets as the base material for 3D printing powders. The expanded TPU contains closed-cell foam structures with air pockets distributed throughout the material, creating inherent porosity. This porous structure reduces the overall density and weight of the 3D printed parts while maintaining the polyurethane's elastic properties and rebound resilience, directly resolving the contradiction between weight reduction and mechanical performance retention.
Solution Approach 2:
The patent employs composite materials by combining expanded TPU pellets with conventional TPU powders or other auxiliary agents to create a hybrid powder mixture for 3D printing. The expanded TPU provides lightweight porous structure while the conventional TPU components ensure proper bonding and mechanical integrity during the printing process, achieving both weight reduction and maintained mechanical properties in the final printed parts.
2Weight of moving object
If the density of 3D printed parts is reduced for lightweight applications, then the weight is decreased, but the mechanical properties and rebound resilience deteriorate
Solution Approach 1:
The patent utilizes porous materials by selecting expanded TPU pellets as the starting material, which inherently possess a lightweight foam structure with controlled porosity. The expansion process creates a cellular structure that reduces density while preserving the polyurethane matrix's mechanical integrity. This allows the 3D printed parts to achieve low weight without sacrificing rebound resilience or other mechanical properties, as the porous structure is built into the material itself rather than being a compromise of the base material.
Solution Approach 2:
The patent applies parameter changes by controlling the expansion ratio, particle size distribution, and density of the expanded TPU pellets to optimize the balance between weight and mechanical properties. By adjusting these parameters during material preparation and printing process parameters, the patent achieves lightweight parts with sufficient mechanical strength and rebound resilience for specific applications, resolving the contradiction through precise parameter optimization.
3Manufacturing precision
If expanded TPU pellets are pulverized to create fine powders, then the particle size is reduced for better printing quality, but the bulk density increases and lightweight properties are lost
Solution Approach 1:
The patent applies local quality by creating a bimodal or multimodal particle size distribution in the powder mixture, where a portion of the expanded TPU pellets is pulverized to fine sizes for good printing quality and surface finish, while a larger portion is retained at coarser sizes to maintain low bulk density and lightweight properties. This local differentiation of particle sizes allows the system to achieve both printing precision and weight reduction simultaneously, as different regions of the powder bed serve different functional purposes.
Solution Approach 2:
The patent employs partial action by selectively pulverizing only a portion of the expanded TPU pellets rather than all of them. This partial pulverization approach creates a powder mixture with diverse particle sizes, where the fine pulverized particles provide printing quality and the coarser unpulverized particles maintain low density. This partial application of the pulverization process resolves the contradiction by achieving sufficient printing quality without the excessive density increase that would result from complete pulverization.
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 TPU powders enable the creation of 3D products with low density, high rebound resilience, and improved mechanical properties, such as elongation at break, suitable for various applications including footwear and automotive components, while allowing for recycling and reuse of materials.
Implementation Method 1
selective laser sintering (SLS)
Data Source
AI summary
This disclosure relates to thermoplastic polyurethane (TPU) powders derived from expanded TPU and/or molding part thereof, wherein the average particle size D50 of the powders is no more than 1 mm, to a 3D molding formed from the same and to a process of forming the 3D molding. The TPU powders of the present invention can be used to prepare 3D products with low density, high rebound resilience and good mechanical properties, and the TPU powders of the present invention can be derived from a wide range of sources, and the TPU powders and 3D products of the present invention can be easily reused.