Composite Powder Coating for Laser Sintering Segregation
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Solution Overview
Problem
Existing powder mixtures for rapid prototyping and manufacturing often experience segregation phenomena due to differences in density between polymer particles and fillers, leading to inconsistent mechanical properties and handling issues, which affect the quality and uniformity of produced components.
Innovation Solution
A powder comprising composite particles with core particles made from a second polymer, coated with a precipitated first polymer, where the ratio of the average grain diameter of the composite particles to the core particles is 1.5 or greater, ensuring a solid bond and preventing segregation, thereby improving the constancy of mechanical properties and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If powder mixtures containing polymer particles and fillers are used for rapid prototyping, then reinforcement and mechanical properties can be improved, but segregation phenomena occur due to density differences leading to inconsistent mechanical properties
Solution Approach 1:
The patent merges the filler particles and polymer matrix into a single composite particle structure, where filler particles are embedded within polymer particles to form core-shell or hybrid composite particles. This eliminates segregation by combining previously separate components into an integrated unit that behaves as one homogeneous material during handling and processing.
Solution Approach 2:
The patent creates composite particles consisting of filler particles combined with polymer particles through coating or embedding processes. These composite particles exhibit properties of both constituents while preventing segregation, as the filled polymer particles form a unified structure with optimized mechanical properties and consistent composition throughout the powder mixture.
2Strength
If filled polymer particles are used to improve mechanical properties, then reinforcement is achieved, but handling issues and inconsistent mechanical properties arise due to segregation
Solution Approach 1:
By combining filler and polymer into single composite particles, the patent eliminates the handling problems associated with heterogeneous powder mixtures. The unified composite particle structure flows and handles consistently like homogeneous powder, while maintaining the reinforcement benefits of the filler content.
3Productivity
If conventional powder mixtures are used for laser sintering, then rapid prototyping can be performed, but warping and inconsistent quality occur due to segregation
Solution Approach 1:
The patent employs composite particles with filler embedded in polymer matrices, creating material with optimized and consistent properties throughout. This eliminates the composition variations that cause warping and quality inconsistencies during laser sintering, while maintaining the rapid prototyping capability through suitable melting behavior of the polymer component.
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 solution prevents segregation, resulting in uniform components with improved mechanical properties and reduced warping, allowing for larger packaging and uniform energy input during laser sintering, enhancing the reproducibility and quality of produced parts.
Implementation Method 1
core particles which are completely or partially coated with a precipitated first polymer
Implementation Method 2
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 3
The energy input is achieved via electromagnetic radiation
Implementation Method 4
The melted particles run into each other and quickly solidify again into a solid mass
Data Source
AI summary
Powder comprises composite particles comprising a core particle, which is completely or partially coated with the precipitated first polymer, and the core particle comprises a second polymer or made of a second polymer, which is different from the precipitated first polymer. The ratio of the median diameter of the composite particles to the median diameter of the core particles is >= 1.15. Independent claims are also included for: (1) producing the powder, comprising: contacting the polymer under the action of pressure and/or temperature with a medium containing a solvent, which dissolves the first polymer, to generate at least partial solution in the presence of core particles, and then precipitating the first polymer from at least partial solution to obtain the composite particles; and (2) producing a molding by layer-by-layer process comprising selectively melting the regions of the respective powder layer by introducing electromagnetic energy, where the selectivity is achieved by applying susceptors, inhibitors, or absorbers or by masks, and the powder comprises composite particles which are produced by core particles coated entirely or partially with a precipitated first polymer.