Polyamide Powder for Selective Laser Sintering
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Solution Overview
Problem
Conventional polymer powders used in rapid prototyping processes suffer from gaseous evolution of residual monomers, leading to sublimation and reduced precision and reliability, especially when used in long construction processes, requiring costly extraction steps to mitigate these issues.
Innovation Solution
A polymer powder based on polyamides with medium-sized lactam rings, such as enantholactam, caprylolactam, or caprinolactam, is developed through polycondensation and precipitative crystallization, resulting in a powder with low residual monomer content and improved processing characteristics, eliminating the need for extraction steps and minimizing sublimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymer powders are used in rapid prototyping processes, then the process can be conducted without extraction steps, but gaseous evolution of residual monomers occurs leading to sublimation and reduced precision and reliability
Solution Approach 1:
The patent applies preliminary action by conducting extraction steps during the powder preparation phase before the rapid prototyping process. This removes residual monomers from the polymer powder in advance, preventing gaseous evolution and sublimation during subsequent processing. The extraction is performed using solvents like alcohol or water under controlled conditions (heating, stirring, filtration) to ensure thorough monomer removal, thereby eliminating the source of precision and reliability problems in later stages.
2Manufacturing precision
If extraction steps are conducted to remove residual monomers, then sublimation and precision issues are reduced, but the process complexity and cost increase
Solution Approach 1:
The patent applies self-service by utilizing the polymer powder's own properties to facilitate monomer removal. The extraction process leverages the solubility characteristics of the polymer matrix and residual monomers in common solvents like alcohol or water. By controlling temperature, stirring rate, and extraction time, the system uses its inherent chemical properties to achieve effective monomer removal without requiring complex external equipment or multiple processing stages, thereby reducing overall process complexity while maintaining high dimensional accuracy.
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 polymer powder achieves enhanced dimensional accuracy, surface quality, and processing reliability, with reduced sublimation and improved reproducibility in rapid prototyping, maintaining mechanical properties comparable to conventional powders without the need for additional extraction steps.
Implementation Method 1
polymer powder based on a polyamide, in particular on a polyamide prepared via polycondensation of enantholactam, caprylolactam, pelargolactam or caprinolactam
Implementation Method 2
precipitative crystallization, resulting in a powder with low residual monomer content
Implementation Method 3
selective laser sintering (SLS). This process selectively and briefly irradiates plastics powders in a chamber with a laser beam, the result being that the powder particles impacted by the laser beam melt
Implementation Method 4
The introduction of energy is achieved by way of electromagnetic radiation
Implementation Method 5
The molten particles coalesce and rapidly solidify again to give a solid mass
Implementation Method 6
The selectivity of the layer-by-layer process may be achieved by way of the application of susceptors, absorbers, inhibitors, or masks, or by way of focused introduction of energy
Data Source
AI summary
The present invention relates to a polymer powder which comprises polyamide, and to the use of this powder for shaping processes, and also to moldings produced from this polymer powder. The shaping processes are layer-by-layer processes which use powders, where regions of the respective layer are selectively melted via introduction of electromagnetic energy. The selectivity may be achieved, with no intention of restricting the invention thereto, be achieved via masks, application of inhibitors, of absorbers, or of susceptors, or via focusing of the energy introduced. After cooling, the regions then solidified can be removed in the form of moldings from the powder bed.