Copolyamide Powder for Selective Laser Sintering
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Solution Overview
Problem
Existing polymer powders for mouldless shaping processes face challenges such as curl distortion, non-uniform crystallinity, high BET surface area leading to impaired flowability, and compromised dimensional accuracy due to high viscosity and sharp-edged particles, which are difficult to control and result in unreliable rapid manufacturing processes.
Innovation Solution
A specific copolyamide powder produced using laurolactam, ω-aminoundecanoic acid, dodecanedioic acid or sebacic acid, and decanediamine or dodecanediamine monomer units, which allows for selective melting and bonding at low temperatures, achieving low viscosity, high density, and precise control over crystallinity, thereby overcoming the limitations of existing powders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polymer powders are used in mouldless shaping processes, then the process can be performed, but curl distortion and non-uniform crystallinity occur leading to poor dimensional accuracy
Solution Approach 1:
The patent modifies the chemical composition parameters of the polymer powder by incorporating specific copolyamide structures with controlled monomer ratios. This changes the thermal and rheological parameters of the material, enabling uniform crystallinity and reducing curl distortion during the shaping process, thereby improving dimensional accuracy and process reliability
Solution Approach 2:
The patent uses composite polymer structures formed by copolymerization of multiple monomers (caprolactam, adipic acid, hexamethylenediamine, and other dicarboxylic acids/diamines). This composite material approach creates a powder with optimized crystallization behavior and reduced shrinkage, resolving the contradiction between manufacturing precision and process reliability
2Ease of operation
If polymer powders with high BET surface area are used, then powder flowability is impaired, but using mechanical operations to reduce surface area increases device complexity
Solution Approach 1:
The patent changes the surface area parameter by optimizing the polymerization and grinding process to produce particles with specifically controlled surface areas (0.5-5.0 m²/g). This parameter optimization improves powder flowability without requiring additional mechanical reduction operations, thus avoiding increased device complexity
Solution Approach 2:
The patent performs preliminary surface area control during the powder production stage itself, rather than requiring subsequent mechanical reduction. The copolyamide powder is produced with inherently suitable surface area characteristics, eliminating the need for additional mechanical operations and reducing device complexity
3Manufacturing precision
If polymers with high viscosity are used, then dimensional accuracy is compromised, but reducing viscosity may affect material strength
Solution Approach 1:
The patent changes the viscosity parameter by selecting specific copolyamide compositions with controlled molecular weights and monomer distributions. The resulting powder exhibits optimized viscosity characteristics that enable accurate shaping while maintaining adequate material strength in the final moulding
Solution Approach 2:
The patent employs composite copolymer structures where the combination of different monomers creates a material with balanced rheological and mechanical properties. The copolymer architecture provides low enough viscosity for dimensional accuracy during processing while maintaining sufficient strength in the solidified moulding
4Reliability
If sharp-edged particles are used, then flowability is impaired and processing becomes unreliable, but rounding particles increases processing time
Solution Approach 1:
The patent changes the particle morphology parameter by controlling the grinding and classification process to produce particles with specifically optimized shapes. The particles have sufficiently rounded edges for reliable flow and processing, but not so extensively processed that excessive time is lost, achieving an optimal balance between reliability and processing speed
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 copolyamide powder enables high processing reliability, low shrinkage, and excellent dimensional accuracy, with a smooth melt film formation and improved flowability, allowing for the production of dense and accurately dimensioned mouldings without the need for additional mechanical operations to reduce surface area.
Implementation Method 1
selective laser sintering. In this process, plastics powders in a chamber are selectively and briefly radiated with a laser beam, whereupon the powder particles impacted by the laser beam melt
Implementation Method 2
the powder particles impacted by the laser beam melt. The molten particles coalesce and rapidly solidify again to give a solid mass
Implementation Method 3
The energy is introduced by way of electromagnetic radiation
Implementation Method 4
The molten particles coalesce and rapidly solidify again to give a solid mass
Data Source
AI summary
A task often encountered in very recent times is the rapid provision of prototypes. Particularly suitable processes are those based on pulverulent materials and in which the desired structures are produced layer-by-layer through selective melting and solidification. The invention provides the constitution, production and use of a copolyamide powder which was produced using the following monomer units: a) laurolactam or ω-aminoundecanoic acid, and also b) dodecanedioic acid, and either c) decanediamine or dodecanediamine, in shaping processes, and also to moldings produced through a layer-by-layer process which selectively melts regions of a powder layer, using this specific powder. Once the regions previously melted layer-by-layer have been cooled and solidified, the molding can be removed from the powder bed. The moldless layer-by-layer processes for the production of components using the copolyamide powder result in simplified and more reliable conduct of the process and better recyclability.