Fluidized Powder Bed Sintering for Faster Additive Manufacturing
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Solution Overview
Problem
Laser sintering technology for additive manufacturing is limited by the availability of powders with good flowability, high costs, limited preheating range, fabrication speed, temperature control issues, inefficient heat removal, and difficulty in producing articles with gradients in composition.
Innovation Solution
The system fluidizes a bed of powder and uses a directed energy beam to sinter particles in selected target areas, allowing for a wide range of powder types and compositions, efficient heat transfer, and continuous deposition of powder through an open porous structure, enabling faster build times and reduced costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser sintering is used with traditional roller-based powder deposition, then manufacturing precision is achieved, but fabrication speed is limited and productivity is reduced
Solution Approach 1:
The invention extracts and eliminates the roller-based powder deposition step from the traditional laser sintering process. By using a fluidized bed to directly supply powder to the build area, the time-consuming mechanical layering operation is removed entirely, enabling continuous fabrication and dramatically improving productivity.
Solution Approach 2:
The invention replaces the mechanical roller-based powder deposition system with a fluidized bed system that uses fluid dynamics (gas flow) to transport and deposit powder. This substitution eliminates mechanical friction, wear, and slow deposition rates, allowing for much faster powder application and significantly increased fabrication speed.
2Temperature
If traditional laser sintering with quiescent powder bed is used, then temperature control is attempted, but heat removal is inefficient and temperature control worsens
Solution Approach 1:
The invention introduces a fluidized bed system that uses gas flow to continuously move powder particles through the build area. This pneumatic system enables efficient heat removal by constantly replacing heated powder with cooler powder from the fluidized bed reservoir, maintaining optimal temperature control and preventing heat accumulation that would otherwise require complex cooling systems.
Solution Approach 2:
The invention changes the state of the powder bed from quiescent (static) to fluidized (dynamic). By transforming the powder from a stationary mass to a flowing fluid-like state, the system achieves superior heat transfer and temperature control, as the moving particles continuously exchange thermal energy with the gas flow and can be rapidly cooled or heated as needed.
3Adaptability or versatility
If limited powder formulations are used for good flowability, then ease of manufacture is maintained, but adaptability of material selection is reduced
Solution Approach 1:
The fluidized bed system serves multiple functions: it not only deposits powder but also preheats, pre-mixes, and controls powder temperature and flow characteristics. This multi-functionality allows a wide variety of powder formulations (metals, ceramics, polymers, composites) to be processed effectively, as the system can adapt its parameters to handle different material properties while maintaining ease of manufacture.
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 enables the production of complex articles with improved temperature control, increased build speed, and reduced costs by using a fluidized bed to supply powder and manage heat efficiently, allowing for a broader range of materials and gradient properties.
Implementation Method 1
uses a directed energy beam to sinter particles in selected target areas
Implementation Method 2
selectively irradiating the powdered material... the polymer particle partially melts or melts the surface of the particle
Implementation Method 3
Fluidization is a process whereby a granular powder material is converted from a solid-like state to a fluid-like state... passing a fluid (e.g., gas, liquid or supercritical fluid) up through a powder bed
Implementation Method 4
Fluidized beds are also known to provide excellent heat transfer... The upward flow of the fluidizing medium efficiently removes heat supplied by the energy beam
Data Source
AI summary
A system, method and apparatus for additive manufacturing is disclosed. The method includes fluidizing particles with a medium to form a fluidized bed and additively manufacturing an article formed from the particles. The article has an open porous structure defining a plurality of pores and a plurality of fluid paths through the article. The method further includes flowing the particles and the medium through the fluid paths while the fluid paths are being formed. The article may be additively manufactured by selectively sintering the particles at target areas on the article which are near the surface of the fluidized bed.