Multi-chamber Air Knife for Additive Manufacturing
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Solution Overview
Problem
In additive manufacturing, non-uniform air flow from air knives leads to inefficient spatter mitigation, and the devices often occupy valuable space, increasing the risk of contamination during powder deposition.
Innovation Solution
An air knife assembly with a multi-chamber plenum and gas distribution module that delivers gas in a laminar flow across the build platform, retractable for minimizing space usage and reducing contamination risk, and an exhaust unit with a concave plate and heat shield for efficient spatter removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If air knives are used for spatter mitigation, then spatter removal effectiveness is improved, but device complexity and space occupation increase
Solution Approach 1:
The air knife assembly is divided into multiple independent chambers (first chamber, second chamber, third chamber) that are fluidically connected. Each chamber can be independently designed and manufactured, and the segmented structure allows for modular assembly, reducing overall system complexity while maintaining effective spatter mitigation across the entire build platform width.
Solution Approach 2:
The air knife assembly utilizes a vertical stacking arrangement of chambers (first chamber at higher elevation than second chamber, which is higher than third chamber) to deliver gas flow across the build platform. This vertical dimensionality change allows the air knife to cover a wider area without increasing horizontal footprint, reducing space occupation while maintaining spatter removal effectiveness.
2Object-affected harmful factors
If air knives are positioned over the build platform, then spatter mitigation is improved, but contamination risk during powder deposition increases
Solution Approach 1:
The air knife assembly is designed to be retractable, allowing it to be extracted or retracted away from the build platform when not in use. This extraction capability eliminates the air knife from the powder deposition zone, removing the source of potential contamination while maintaining spatter mitigation functionality when extended during the fusion process.
Solution Approach 2:
The air knife assembly transitions from a static position to a dynamic, movable configuration. It can be extended over the build platform during fusion operations to provide spatter mitigation, then retracted during powder deposition to eliminate contamination risk. This dynamic positioning resolves the contradiction between maintaining spatter control and preventing contamination.
3Productivity
If gas flow is delivered across the platform, then spatter removal is improved, but gas flow uniformity deteriorates
Solution Approach 1:
Each chamber in the air knife assembly is designed with specific local characteristics - the first chamber delivers gas at a higher elevation, the second chamber at an intermediate elevation, and the third chamber at a lower elevation. This local quality differentiation in vertical positioning creates overlapping gas flow patterns that collectively achieve uniform horizontal gas distribution across the entire build platform while maintaining high spatter removal efficiency.
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 provides uniform gas flow across the platform, effectively reduces spatter and contamination, and allows for efficient use of space in the manufacturing system, improving the quality and production efficiency of parts.
Implementation Method 1
The gas distribution module is configured to discharge the gas in a laminar flow parallel to a top surface of the build platform
Implementation Method 2
The plurality of vertically stacked chambers are configured to guide the gas from the gas inlet to the collection chamber
Implementation Method 3
an exhaust unit to receive gas from over the platform
Data Source
AI summary
An additive manufacturing apparatus includes a platform, a dispenser configured to deliver a plurality of successive layers of feed material onto the platform, at least one energy source to selectively fuse feed material in a layer on the platform, and an air knife assembly. The air knife assembly includes an inlet unit to deliver gas over the platform and an exhaust unit to receive gas from over the platform. The inlet unit includes a multi-chamber plenum, a gas inlet, and a gas distribution module. The multi-chamber plenum has a plurality of vertically stacked chambers that are fluidically connected, with a first chamber of the plurality of vertically stacked chambers positioned at a higher elevation than a collection chamber of the plurality of vertically stacked chambers.