Powder Bed Gas Collection Overlapping the Laser Melt Zone
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Solution Overview
Problem
In additive manufacturing processes like direct metal laser melting, weld spatter and smoke contaminants often form metallurgical defects in the object due to the limited gas supply velocity and pressure, which fail to effectively remove these contaminants from the powder bed.
Innovation Solution
A system and method that includes an array of laser emitters with a field of view and a spatter collection device with a diffuser and collector, translating in a coordinated motion to create a precise collection zone for efficient removal of contaminants using a concentrated inert gas stream, ensuring the powder bed remains undisturbed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If gas supply velocity and pressure are increased to remove weld spatter and smoke, then contaminant removal effectiveness is improved, but the powder bed becomes disturbed
Solution Approach 1:
The gas flow system is segmented into multiple zones: a first gas flow path for contaminant removal and a second gas flow path for powder bed stabilization. This segmentation allows independent optimization of each function, enabling effective contaminant removal without disturbing the powder bed
Solution Approach 2:
Different gas flow characteristics are applied to different regions: high-velocity gas flow is directed at the melt pool area for contaminant removal, while low-velocity gas flow is applied to the powder bed surface to maintain stability. This local differentiation resolves the contradiction between contaminant removal effectiveness and powder bed stability
2Productivity
If a gas diffuser is positioned close to the powder bed for effective contaminant collection, then contaminant removal efficiency is improved, but the gas stream disturbs the powder bed
Solution Approach 1:
The gas flow system is divided into separate functional zones with distinct velocity characteristics. The first gas flow path provides high-velocity flow for contaminant entrainment, while the second gas flow path provides low-velocity flow for powder bed stabilization, eliminating the need to choose between collection efficiency and powder bed stability
Solution Approach 2:
A second gas flow acts as an intermediary stabilization mechanism that counteracts the disruptive effects of the first gas flow on the powder bed. This intermediary gas stream maintains powder bed stability while allowing the primary gas flow to effectively remove contaminants
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 effectively reduces the likelihood of manufacturing defects by efficiently collecting weld spatter and smoke particles, allowing for larger powder bed areas and maintaining the integrity of the powder bed during the build operation.
Implementation Method 1
a diffuser configured to discharge a stream of gas across the powder bed
Implementation Method 2
contaminants entrained in the stream of gas are channeled towards, and collected by, the gas collection plenum
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
Implementation Method 4
The array is configured to melt at least a portion of the powder bed within the field of view
Implementation Method 5
a collector configured to receive the stream of gas and contaminants entrained in the stream of gas
Data Source
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.