Polyketone Powder Composition for Low-Stress Laser Sintering
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Solution Overview
Problem
Existing additive manufacturing methods using crystalline or semicrystalline thermoplastic polymers face limitations in producing large or complex parts due to high residual stresses, which can lead to deformation or unacceptable tolerances, and are restricted by the limited polymers suitable for selective laser sintering and multi-jet fusion techniques.
Innovation Solution
Development of aliphatic polyketone powders with specific thermal characteristics, including bimodal or non-overlapping melt and recrystallization peaks, and controlled particle morphology, enabling their use in floating powder bed methods like SLS, HSS, and MJF without significant deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crystalline or semicrystalline thermoplastic polymers are used in powder bed-based 3D printing, then the polymers can be successfully printed, but high residual stresses cause deformation or unacceptable tolerances
Solution Approach 1:
The patent changes the thermal parameters of the polymer by selecting materials with specific melting and recrystallization temperature characteristics. The key parameter change is using polymers where the recrystallization temperature is sufficiently below the melting temperature, creating a wide processing window that allows complete recrystallization before solidification, thereby minimizing residual stresses and deformation while maintaining printability
Solution Approach 2:
The patent exploits the phase transition behavior of crystalline and semicrystalline polymers during printing. By controlling the cooling rate and temperature profile, the polymer undergoes complete recrystallization in the wide temperature window between melting and recrystallization points, ensuring uniform solidification and minimizing residual stresses that cause deformation
2Manufacturing precision
If the temperature window between melting and recrystallization is small, then residual stresses are minimized, but the selection of suitable polymers is limited
Solution Approach 1:
Instead of trying to find polymers with small temperature windows, the patent inverts the approach by selecting polymers with large temperature windows and then controlling the printing parameters to utilize this advantage. The wide window allows complete recrystallization, and the patent systematically identifies multiple polymer classes (polyamides, polyesters, polycarbonates, etc.) that exhibit this behavior, thereby expanding versatility while maintaining precision
3Ease of operation
If reactor flake polyketone is heated and extruded to form pellets, then handling and shipping difficulty is reduced, but the fine particle size characteristics are lost
Solution Approach 1:
The patent extracts only the necessary property (adequate particle size for handling) from the pelletization process while discarding the harmful effect (loss of fine particle size characteristics). By carefully controlling the extrusion and cooling parameters, the patent produces pellets that are large enough for easy handling but maintain the fine internal structure and particle size distribution needed for successful additive manufacturing
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 polyketone powders exhibit high strength, toughness, and temperature resistance, allowing for the production of complex parts with minimal residual stress and good recyclability, suitable for various applications including biocompatible, electrical, transportation, and industrial uses.
Implementation Method 1
Selective laser sintering (SLS) is a 3D-printing technique that uses a laser to fuse powder material in successive layers
Implementation Method 2
High-speed sintering (HSS) and multi-jet fusion (MJF) 3D-printing employ multiple jets that similarly deposit successive layers of infrared-absorbing (IR-absorbing) ink onto powder material, followed by exposure to IR energy for selective melting of the powder layer
Implementation Method 3
a free-body diagram of a 3D printed object can be used to determine the residual stresses expected in the printed object. This is necessary for successfully building the object. If the residual stress is too high, the object will deform or be deformed beyond acceptable tolerances
Data Source
AI summary
In one instance a semicrystalline polyketone powder useful for additive manufacturing is comprised of a bimodal melt peak determined by an initial differential scanning calorimetry (DSC) scan at 20° C./min and a D90 particle size of at most 300 micrometers and average particle size of 1 micrometer to 150 micrometers equivalent spherical diameter. In another instance, A composition is comprised of a semicrystalline polyketone powder having a melt peak and a recrystallization peak, wherein the melt peak and recrystallization peak fail to overlap.