Supraparticle Powder for Additive Manufacturing Flowability
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Solution Overview
Problem
Current powder materials for selective laser sintering in additive manufacturing face challenges with poor flowability, low powder bed packing density, and inadequate mechanical properties due to irregular particle shapes and irreversible molecular changes during processing, limiting the flexibility and performance of three-dimensional objects.
Innovation Solution
The development of supraparticles comprising thermoplastic polymeric primary particles with controlled particle sizes and morphologies, formed through agglomeration and partial sintering, which are then processed using spray drying to create powders with improved flowability and packing density, allowing for precise adjustment of composition and morphology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If top-down approaches like cryogenic grinding or wet grinding are used to produce polymer particles, then particle size can be reduced to microscale, but particle shape becomes irregular and flowability deteriorates
Solution Approach 1:
Instead of using top-down approaches that start with bulk polymer and grind it down (which creates irregular shapes), the invention uses bottom-up approaches that build particles from molecular precursors through controlled polymerization. This inverse strategy produces spherical particles with smooth surfaces that maintain excellent flowability while achieving the desired microscale size range.
Solution Approach 2:
The invention changes the fundamental parameters of particle formation by using controlled polymerization conditions (temperature, initiator concentration, monomer ratio) to directly produce particles with specific size distributions and spherical morphologies. This parametric control during synthesis eliminates the flowability problems associated with mechanical grinding while achieving the required particle size reduction.
2Volume of moving object
If cryogenic mechanical milling is used to reduce particle size, then microscale particles can be obtained, but irreversible molecular structural changes occur that negatively affect thermal properties
Solution Approach 1:
Rather than mechanically breaking down bulk polymer (top-down), the invention synthesizes particles directly at the molecular level through controlled polymerization (bottom-up). This approach avoids all mechanical stress that would cause irreversible molecular structural changes, preserving the thermal properties and crystallization behavior of the polymer while achieving the desired microscale particle size.
3Strength
If filled powder materials with mechanically blended additives are used, then mechanical properties can be improved, but processability and powder bed properties deteriorate
Solution Approach 1:
The invention merges the polymer matrix and filler materials at the nanoscale level through simultaneous synthesis or intimate mixing during particle formation. This creates a homogeneous composite structure where fillers are uniformly distributed within the polymer matrix at the molecular level, maintaining excellent flowability and powder bed properties while achieving enhanced mechanical properties through the synergistic combination of materials.
Solution Approach 2:
The invention changes the scale of additive mixing from macro-scale mechanical blending to nano-scale molecular dispersion. By controlling the size and distribution of filler particles at the nanometer scale and their intimate integration with the polymer matrix during particle formation, the invention maintains powder flowability and processability while achieving superior mechanical properties through enhanced interfacial area and uniform stress distribution.
4Productivity
If conventional polymer powders are used for selective laser sintering, then processing can be performed, but dimensional accuracy and mechanical properties of manufactured objects are limited
Solution Approach 1:
The invention changes critical parameters of the powder material including particle size (reducing to microscale with narrow distribution), particle shape (spherical with smooth surfaces), and surface characteristics (controlled roughness through synthesis conditions). These parameter changes result in improved powder flowability, higher packing density, and better laser energy absorption, which collectively enhance dimensional accuracy and mechanical properties of the sintered objects while maintaining processing capability.
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 approach results in higher dimensional accuracy and improved mechanical properties of three-dimensional objects, enabling better processability and performance in additive manufacturing by optimizing powder flow and bed density.
Implementation Method 1
wherein the first primary particles are thermoplastic polymeric particles, wherein the first primary particles have a volume-averaged median particle diameter (x50,3) of from 10 to 2000 nm... wherein the primary particles are agglomerated and/or partially sintered together to form the supraparticles
Implementation Method 2
c) removing all dispersion media, preferably evaporating all dispersion media by spray drying, thereby obtaining supraparticles
Implementation Method 3
removing all dispersion media, preferably evaporating all dispersion media by spray drying, thereby obtaining supraparticles
Data Source
AI summary
The present invention relates to a powder for the preparation of three-dimensional objects comprising, or consisting of, supraparticles (8,9,10) comprising at least a first population of first primary particles, wherein the first primary particles are thermoplastic polymeric particles, wherein the first primary particles have a volume-averaged median particle diameter of from 10 to 2000 nm; wherein the primary particles are agglomerated and/or partially sintered together to form the supraparticles, and/or wherein the supraparticles have a volume-averaged median particle diameter of from 2.5 to 100 pm. The invention also relates to a method for preparing in a powder for the preparation of three-dimensional objects comprising a1) providing an at least first population of first primary particles in a first dispersion medium, thereby forming a first dispersion (1); and/or a2) providing an at least second population of second primary particles in a second dispersion medium, thereby forming a second dispersion (2); and/or a3) mixing the first dispersion and the second dispersion, thereby forming a mixture (3) of the first and second dispersion; and b) atomizing (5) the first, second or mixture of the first and second dispersion thereby forming droplets of the first, second or mixture of the first and second dispersion; and c) removing all dispersion media, preferably evaporating all dispersion media by spray drying (7), thereby obtaining supraparticles (8,9,10).