Spherical Polymer Powder via Dispersion for Additive Manufacturing
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Solution Overview
Problem
Current rapid prototyping and manufacturing processes are limited by the need for round grain-shaped powders, which restrict material selection, particularly for high-melting polymers and additives like impact modifiers, due to poor flow properties and difficulty in achieving thorough mixing, leading to issues with density, surface quality, and segregation during processing.
Innovation Solution
A process involving mixing a polymer or copolymer with a water-soluble polymeric polyol, dissolving the mixture in water to form a dispersion, separating and washing the particles, and drying them, using polyethylene glycol or polyvinyl alcohol to produce a powder suitable for layer-by-layer tool-free production, allowing for higher-melting polymers and improved flowability and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ground polymer powder is used, then material selection is expanded, but flow properties deteriorate due to sharp edges causing poor flow and grooves during layer application
Solution Approach 1:
The patent applies spheroidality by producing polymer powder with spherical particle morphology through a dispersion process. The polymer is dissolved in a solvent, the solution is dispersed into droplets, and upon solvent evaporation, spherical particles are formed. This spherical shape eliminates the sharp edges present in ground powder, thereby improving flow properties while enabling the use of various polymer materials including high-melting polymers that cannot be easily ground.
2Adaptability or versatility
If high-melting polymers are processed using conventional methods, then material versatility is improved, but particle shape control deteriorates leading to non-spherical particles with poor flow
Solution Approach 1:
The patent applies parameter changes by controlling the phase state of the polymer during processing. High-melting polymers are processed in the dissolved state rather than the solid state, allowing them to be formed into spherical particles through dispersion. The key parameters controlled are: (1) solvent selection to dissolve the high-melting polymer, (2) dispersion conditions to form uniform droplets, and (3) evaporation rate to control particle morphology. This approach enables spherical particle formation for polymers with melting points above conventional processing temperatures.
3Reliability
If additives like impact modifiers are mixed into powder, then functional properties are improved, but mixing thoroughness deteriorates leading to segregation and non-uniform distribution
Solution Approach 1:
The patent applies merging by combining the polymer and additives in the dissolved state before particle formation. The polymer is dissolved in a solvent, additives are mixed into the solution, and then the entire mixture is dispersed into droplets. Upon solvent evaporation, all components are simultaneously incorporated into each particle, ensuring homogeneous distribution. This eliminates the segregation problem that occurs when additives are mixed into pre-formed powder, as the components are locked into a uniform distribution during the particle formation process itself.
4Ease of manufacture
If conventional precipitation processes are used, then polymer powder is produced, but solubility requirements limit material selection to only soluble polymers
Solution Approach 1:
The patent applies the intermediary principle by using a solvent as a medium to enable processing of insoluble polymers. The solvent acts as an intermediary that temporarily dissolves the polymer, allowing it to be processed in a molecularly dispersed state. After particle formation and solvent evaporation, the polymer ends up in spherical particles. The key is selecting a solvent that can dissolve the specific polymer at processing conditions but evaporates completely during particle formation, leaving no residue. This intermediary approach enables processing of polymers that would otherwise be impossible to process into spherical powder.
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 method enables the processing of high-melting polymers into powders with improved flowability and mechanical properties, reducing manufacturing costs and environmental impact, and enhancing the quality and reusability of the powder, while avoiding the limitations of existing methods such as decomposition and brownish discoloration.
Implementation Method 1
dissolving the mixture in water to form a dispersion
Implementation Method 2
separating the polymer or copolymer particles from the dispersion
Implementation Method 3
plastic powders are selectively briefly exposed to a laser beam in a chamber, causing the powder particles hit by the laser beam to melt
Implementation Method 4
The melted particles run into each other and quickly solidify again into a solid mass
Implementation Method 5
The energy input is achieved via electromagnetic radiation
Implementation Method 6
mixing a polymer or copolymer with at least one water-soluble polymeric polyol, dissolving the mixture in water to form a dispersion
Data Source
AI summary
Preparation of a powder, in the process of a layer-wise tool free production of three-dimensional molded bodies, in which the selective areas of the respective powder layer is melted using the electro magnetic energy, comprises mixing a polymer or copolymer with at least a water-soluble polymer polyol, dissolving the obtained mixture in water to obtain a dispersion, separating the polymer- or copolymer particle from the dispersion, washing and drying the separated polymer or copolymer particles, where the polymer polyol is polyethylene glycol or polyvinyl alcohol. Independent claims are included for: (1) the powder comprising at least a polymer or copolymer powder containing 0.001-5 wt.% of the polymer polyol; and (2) molded bodies, obtained using the powder.