Polyamide Powder for Layer-by-Layer Manufacturing
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Solution Overview
Problem
Existing layer-by-layer manufacturing processes face challenges in achieving maximum surface quality and dimensional accuracy due to curl distortion and heat conduction issues, which require maintaining a uniform temperature just below the melting point of polymeric materials, leading to potential protrusions and deviations from intended contours.
Innovation Solution
The use of specific XY-type polyamides prepared via polycondensation of diamines and dicarboxylic acids, such as PA1010, PA1012, or PA1212, which exhibit high enthalpy of fusion and recrystallization temperatures, allowing for improved processing and mechanical properties while minimizing curl and enhancing surface quality and dimensional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polyamide powders are used in layer-by-layer manufacturing processes, then the process can be carried out, but curl distortion occurs and surface quality and dimensional accuracy are compromised
Solution Approach 1:
The patent applies parameter changes by modifying the thermal properties of the polyamide powder through controlled crystallization. Specifically, the powder is crystallized at temperatures of 40-80°C to achieve a crystallinity of 10-40%, which fundamentally changes the melting behavior and reduces the enthalpy of fusion. This parameter modification eliminates curl distortion while maintaining manufacturing precision.
Solution Approach 2:
The patent applies partial action by performing only a portion of the crystallization process at controlled temperatures (40-80°C) rather than complete crystallization at higher temperatures. This partial crystallization achieves the desired crystallinity range (10-40%) that optimizes both surface quality and dimensional accuracy without excessive structural changes.
2Ease of operation
If the construction chamber temperature is maintained just below the melting point to avoid curl, then curl distortion is reduced, but heat conduction causes protrusions and deviations from intended contours
Solution Approach 1:
The patent changes the thermal parameters of the polyamide powder by controlling crystallization at 40-80°C to achieve 10-40% crystallinity. This fundamentally alters the heat conduction properties and melting behavior, allowing the material to resist thermal deformation while maintaining ease of processing. The modified thermal parameters prevent both curl distortion and heat-induced protrusions.
Solution Approach 2:
The patent converts the potentially harmful effect of heat conduction into a benefit by modifying the crystalline structure through controlled crystallization. The resulting 10-40% crystallinity creates a material that naturally resists thermal deformation, turning what would be a source of distortion into a stabilizing factor that improves surface quality while maintaining process stability.
3Measurement precision
If high enthalpy of fusion is used to achieve sharp melting peak, then selectivity of melting is improved, but heat conduction and radiation cause severe deviation from intended contours
Solution Approach 1:
The patent fundamentally changes the enthalpy of fusion parameter by controlling the crystallization process at 40-80°C to achieve 10-40% crystallinity. This parameter change results in a reduced enthalpy of fusion that prevents severe thermal deformation while maintaining adequate melting selectivity through the controlled crystalline structure.
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 described polymer powder enables the production of moldings with superior surface quality and dimensional accuracy, comparable to conventional polyamide powders, while maintaining good mechanical properties and processability, and offers improved recycling capabilities due to its high recrystallization temperature.
Implementation Method 1
The introduction of energy is achieved by way of electromagnetic radiation
Implementation Method 2
selectively and briefly irradiates plastics powders in a chamber with a laser beam
Implementation Method 3
Both processes operate with full-surface infrared heating to melt the powder
Implementation Method 4
The molten particles coalesce and rapidly solidify again to give a solid mass
Implementation Method 5
via precipitative crystallization, prepare polymer powders
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—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.