Powder Recirculation Control for Stable Additive Manufacturing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing selective solidification methods for building objects using powder materials face challenges in maintaining build quality due to changes in powder particle size distribution and properties, such as moisture content, morphology, and chemical composition, which affect energy absorption and melt pool characteristics, leading to porosity and accuracy issues in the final object.
Innovation Solution
An additive manufacturing machine with a control device that recirculates powder and maintains a common inert gas atmosphere, allowing for the removal of micro build particles and control of particle size distribution, morphology, and chemical composition to ensure consistent build quality by adjusting the ratio of micro and macro particles, and using sensors to monitor and adjust properties in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If powder material is recirculated from the build chamber to the powder dispenser, then productivity is improved by reusing powder, but the particle size distribution changes due to accumulation of micro build particles, deteriorating manufacturing precision
Solution Approach 1:
The invention extracts and removes micro build particles from the recirculated powder material using a control device with a classifier. This separation process maintains the particle size distribution within specified limits, allowing continuous powder recirculation without quality degradation. The micro particles are selectively removed while retaining usable powder material in the recirculation loop.
Solution Approach 2:
The invention monitors and controls particle size distribution parameters of the powder material throughout the recirculation process. By measuring particle size and adjusting the recirculation and removal processes accordingly, the system maintains optimal particle size characteristics for consistent build quality across multiple builds.
2Productivity
If powder material is transferred between devices and storage, then productivity is improved by efficient powder management, but contamination such as oxidization occurs, deteriorating reliability
Solution Approach 1:
The invention maintains an inert gas atmosphere throughout the entire powder recirculation system, including the build chamber, recirculation loop, control device, and powder dispenser. This continuous inert environment prevents oxidation and contamination of the powder material during transfer and storage, ensuring material purity while enabling efficient powder management.
3Manufacturing precision
If micro build particles are removed from powder material, then manufacturing precision is improved by controlling particle size distribution, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The control device automatically monitors particle size distribution and adjusts the removal of micro build particles without requiring external intervention. The system self-regulates the recirculation and classification processes based on real-time measurements, maintaining precision while minimizing operational complexity.
Solution Approach 2:
The invention incorporates sensors that continuously measure particle size distribution in the recirculated powder and provide feedback to the control device. This closed-loop control enables automatic adjustment of the classification process to maintain optimal particle size distribution, achieving precision through intelligent control rather than mechanical complexity.
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 solution maintains consistent build quality by controlling the particle size distribution and properties of the powder, reducing energy absorption and improving the accuracy and integrity of the final object, while avoiding contamination through a shared inert gas atmosphere.
Implementation Method 1
the beam is scanned across portions of the powder layer that correspond to a cross-section of the object being constructed. The beam melts or sinters the powder to form a solidified layer.
Implementation Method 2
the recirculation loop is in gaseous communication with the build chamber such that the build chamber and the recirculation loop for recirculating powder from the build chamber to the powder dispenser share a common inert gas atmosphere
Implementation Method 3
a control device for removing micro build particles from the powder material to control the particle size distribution of the powder material delivered to the powder dispenser, the micro build particles having a particle size below an upper particle size limit specified for the build
Implementation Method 4
using sensors to monitor and adjust properties in real-time
Data Source
Figure 1
Figure 2
Figure 3
AI summary
This invention concerns an additive manufacturing machine for building objects by layerwise melting of powder material. The machine comprises a build chamber (101) containing a build platform (102), a powder dispenser (108, 109) for depositing the powder material (104) in layers across the build platform (102), a high energy beam for selectively melting powder material (104) in each layer and a control device for controlling a property of the powder material given by build particles in the powder material that are below an upper particle size limit specified for the build. The invention also relates to a method comprising controlling, during the build, a property, such as particle size distribution, of the powder material given by build particles in the powder material that are below an upper particle size limit specified for the build. The invention also concerns a method of carrying out successive builds, wherein in-between the builds, particles are added to or removed from the powder material to effect a property of the powder material given by build particles in the powder material that are below an upper particle size limit specified for the builds. The invention, in particular, concerns adding or removing particles to ensure that a sufficient proportion of micro build particles, such as particles below 10, 5 or 1μm particles, are present in the powder.