Additive Manufacturing Reactive Powder Cross-Linking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current powder-based additive manufacturing processes, such as laser sintering, struggle to produce components with optimal mechanical, thermal, and chemical properties, particularly for complex geometries, as materials like PA12 and TPE exhibit brittleness and low strength due to residual porosity and inadequate cross-linking.
Innovation Solution
A method involving powdery materials with blocked and/or free isocyanate groups (NCO groups) that react during the selective laser sintering process, forming new covalent bonds to enhance mechanical properties, using blocked isocyanates that decompose to release reactive isocyanate groups, which then react with other compounds to create cross-linked polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional thermoplastic powders (PA12, TPE) are used in laser sintering, then the manufacturing process is simple and economical, but the mechanical properties (strength, toughness, elongation) deteriorate significantly compared to injection-molded parts
Solution Approach 1:
The patent changes the chemical parameters of the powder material by incorporating reactive groups (isocyanate, hydroxyl, carboxyl, amino groups) that undergo chemical reactions during or after sintering. This transforms the material from simple thermoplastic to reactive polymer system, enabling cross-linking that dramatically improves mechanical properties while maintaining the additive manufacturing process
Solution Approach 2:
The patent creates composite powder materials combining base polymers with reactive additives containing specific functional groups. These composite powders integrate multiple chemical functionalities (e.g., isocyanate groups for cross-linking, hydroxyl groups for bonding) within a single powder system, achieving enhanced mechanical properties through chemical composition rather than mechanical reinforcement
2Ease of manufacture
If TPE materials are used in laser sintering, then the process is straightforward, but the components exhibit high residual porosity and lose the original strength properties of the TPE material
Solution Approach 1:
The patent extends the useful action beyond the sintering process itself by incorporating post-sintering chemical reactions. The reactive groups continue to react after the thermal process, forming cross-linked networks that progressively eliminate porosity and strengthen the structure, transforming a one-step thermal process into a multi-stage chemical-thermal process
3Strength
If blocked isocyanates are used to enable cross-linking reactions, then mechanical properties improve, but the process complexity increases due to additional chemical reactions and temperature control requirements
Solution Approach 1:
The patent performs preliminary action by pre-blocking the isocyanate groups in the powder material before manufacturing. The blocked isocyanates are stable during storage and handling but release free isocyanate groups at controlled temperatures during or after sintering. This preliminary blocking enables safe handling and precise control of the cross-linking reaction timing, reducing overall process complexity
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
This approach results in improved mechanical properties, including increased modulus of elasticity and melt viscosity, leading to stronger and more durable three-dimensional objects with enhanced thermal and chemical resistance.
Implementation Method 1
blocked isocyanates that decompose to release reactive isocyanate groups
Implementation Method 2
react during the selective laser sintering process, forming new covalent bonds
Implementation Method 3
react with other compounds to create cross-linked polymers
Implementation Method 4
selective laser sintering process
Implementation Method 5
selectively melted using an energy source
Implementation Method 6
selective laser sintering (SLS)
Data Source
AI summary
The invention relates to a method for producing a three-dimensional object by means of a powder-based additive production method from at least one first powdery material, wherein the at least one first powdery material comprises at least one first compound having a first reactive group a). The first reactive group a) is selected from the group consisting of an isocyanate group, a blocked isocyanate group, or a mixture thereof. The invention further relates to a component produced using the method according to the invention, and to powdery material that is suited for the method according to the invention.