Powder Bed Spatter Collection Using Localized Inert Gas Flow
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Solution Overview
Problem
Existing additive manufacturing systems face challenges in efficiently removing weld spatter and smoke contaminants during the build process, which can lead to metallurgical defects in the formed object.
Innovation Solution
An array of low-power laser emitters and a spatter collection device with a diffuser and collector are used to provide a concentrated inert gas stream across a defined collection zone, translating in a coordinated motion with the laser emitters to collect contaminants efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If gas supply velocity and pressure are increased to improve contaminant removal efficiency, then weld spatter and smoke are removed more effectively, but the powder bed becomes disturbed and manufacturing precision deteriorates
Solution Approach 1:
The gas diffuser is positioned specifically over the collection zone (not the entire powder bed) to discharge inert gas locally. This localized gas discharge concentrates the contaminant removal action in a specific area, allowing high-velocity gas flow to be applied only where needed without disturbing the broader powder bed structure.
Solution Approach 2:
An inert gas stream acts as an intermediary medium to transport contaminants from the collection zone to the collection plenum. The gas flow serves as a carrier that removes harmful factors without requiring direct mechanical contact or high-pressure gas discharge that would disturb the powder bed.
2Object-generated harmful factors
If a conventional gas diffuser and collection plenum system is used to remove contaminants, then weld spatter and smoke are collected, but the system complexity increases and space requirements expand
Solution Approach 1:
The collection zone serves multiple functions: it is both the area where contaminants are generated during laser melting and the targeted region for gas discharge and contaminant collection. This multi-functionality reduces the need for separate dedicated structures for each function, simplifying the overall system design.
Solution Approach 2:
The gas diffuser discharges inert gas in a downward direction toward the collection zone, creating a three-dimensional gas flow pattern. This vertical gas discharge approach utilizes the vertical dimension to transport contaminants from the melt zone to the collection plenum, reducing the need for extensive horizontal system components.
3Productivity
If high-powered laser is used to increase build rate, then manufacturing productivity improves, but weld spatter generation increases and contaminant removal becomes more difficult
Solution Approach 1:
The inert gas flow, which could potentially disturb the powder bed if applied broadly, is instead utilized beneficially by concentrating it in the collection zone. The same gas mechanism that could cause harm is converted into a beneficial contaminant removal tool by precise spatial targeting, allowing high-powered laser operation without proportionally increased spatter problems.
Solution Approach 2:
The gas diffuser is positioned and configured to discharge inert gas before contaminants can spread or become embedded in the powder bed. This preliminary gas discharge action prevents contaminant migration and facilitates easier collection, addressing the spatter problem proactively rather than reactively.
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 reduces the likelihood of manufacturing defects by effectively removing contaminants while maintaining the integrity of the powder bed and maintaining a reasonable build rate.
Implementation Method 1
a spatter collection device that provides a stream of inert gas across the collection zone to collect contaminants formed during melting of the powder bed
Implementation Method 2
an array of laser emitters that melts a portion of a powder bed
Implementation Method 3
an object is built layer-by-layer by leveling a powder bed and selectively fusing predetermined portions of the powder bed using a high-powered laser
Data Source
Figure 1
Figure 2
AI summary
An additive manufacturing system including a housing configured to contain a powder bed of material, and an array of laser emitters having a field of view. The array is configured to melt at least a portion of the powder bed within the field of view as the array translates relative to the powder bed. The system further includes a spatter collection device including a diffuser configured to discharge a stream of gas across the powder bed, and a collector configured to receive the stream of gas and contaminants entrained in the stream of gas. The collector is spaced from the diffuser such that a collection zone is defined therebetween, and the spatter collection device is configured to translate relative to the powder bed such that the collection zone overlaps with the field of view of the array.