Thermoplastic Polyurethane Powder Mixture for Additive Manufacturing

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Solution Overview

Problem

Existing additive manufacturing processes face challenges in fine-tuning mechanical and chemical properties of multi-material 3D printed objects, particularly with polyamides, due to wide melting point ranges, limiting the cohesive connection and cost-effectiveness of structural layers.

Innovation Solution

A method using a mixture of powdered thermoplastic polyurethane materials with varying Shore hardness, combined with other additives, to achieve precise control over mechanical and chemical properties through transurethanization reactions, allowing for a wide range of mechanical and chemical properties within a small processing temperature window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple polyamide materials with different melting points are mixed to fine-tune mechanical properties, then material property variation is achieved, but processing temperature control becomes difficult and cohesive connection deteriorates

Engineering Contradiction:
Improvemechanical property variationVSAvoidprocessing temperature control
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter from polyamide to thermoplastic polyurethane, which has a narrow melting point range (150-220°C) compared to polyamides (178-260°C). This allows precise processing temperature control (180-260°C) while still achieving mechanical property variation through Shore hardness differences in the TPU materials.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material strategy by mixing multiple powdered TPU materials with different Shore hardness values (e.g., 80A, 90A, 95A, 98A) in specific weight ratios. This creates a multi-material system where each component contributes different mechanical properties, enabling fine-tuning of the final object's characteristics while maintaining compatible processing temperatures.

Inventive Principle:
Principle #40Composite materials

2Reliability

If processing temperature is increased to melt all materials, then complete melting is achieved, but energy consumption increases and material degradation occurs

Engineering Contradiction:
Improvecomplete meltingVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent selects TPU materials with melting points within 150-220°C, which are lower than polyamides. This allows processing at 180-260°C, achieving complete melting of all TPU components while reducing energy consumption compared to processing polyamides at higher temperatures (178-260°C), and preventing thermal degradation.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If processing temperature is decreased to save energy, then energy consumption is reduced, but melting completeness decreases and layer bonding deteriorates

Engineering Contradiction:
Improveenergy savingVSAvoidlayer bonding quality
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent optimizes the processing temperature range to 180-260°C, which is sufficient to melt TPU materials with melting points of 150-220°C completely. This ensures proper layer bonding and cohesive connection while maintaining energy efficiency, as the temperature is not excessively high like in polyamide processing.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If multiple thermoplastic materials are used to achieve property variation, then mechanical properties can be tuned, but material compatibility and cohesive connection become problematic

Engineering Contradiction:
Improvemechanical property tuningVSAvoidmaterial compatibility
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent uses composite material strategy by mixing multiple powdered TPU materials with different Shore hardness values (e.g., 80A, 90A, 95A, 98A) in specific weight ratios. This creates a multi-material system where each component contributes different mechanical properties, enabling fine-tuning of the final object's characteristics while maintaining compatible processing temperatures.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent maintains material compatibility by using only thermoplastic polyurethane materials, which are chemically compatible and can be processed together. The TPU materials form a homogeneous mixture at the particle level during processing, ensuring cohesive connection and stable composition throughout the object, unlike incompatible material combinations.

Inventive Principle:
Principle #33Homogeneity

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 objects with improved strength, abrasion resistance, and controlled elongation at break, while allowing for spatial variation in properties, resulting in enhanced cohesive layer bonding and cost-effective, resource-efficient manufacturing.

Implementation Method 1

achieving the highest possible cohesive connection of the individual structural layers within the object

Methodology Applied
Scientific EffectTransurethanization reaction: Chemical Bonding

Data Source

PatentEP3615613B1Additive production method with a composite thermoplastic structural material
Publication Date: 2022.08.10 STRATASYS INC

AI summary

The present invention relates to a method for producing an object, comprising the step of producing the object according to an additive production process from a construction material, wherein the construction material comprises a mixture of a plurality of powdery thermoplastic materials which are different from one another due to at least one mechanical property and at least one thermoplastic material is a thermoplastic polyurethane material. The invention also relates to an object obtained according to said method.