Additive Manufacturing Gas Flow Device for Condensate Removal
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Solution Overview
Problem
Existing additive manufacturing methods, particularly in SLM and SLS, face challenges in effectively removing condensate from the build chamber to prevent it from settling on the laser beam window and blocking the path, as parallel gas flows can entrain condensate close to the window.
Innovation Solution
The use of upper gas nozzles oriented to generate jets or streams of gas at acute angles away from the internal surface of the window, combined with a labyrinthine passageway design to ensure uniform gas velocity across the chamber, effectively directs condensate away from the window to an extraction point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a gas flow is introduced through the chamber to remove condensate, then condensate removal is improved, but condensate may be entrained into the flow and brought in close proximity to the window
Solution Approach 1:
Instead of directing gas flow parallel to the window surface (which entrains condensate toward the window), the invention directs the gas flow away from the window surface at an acute angle. This inverted approach reverses the condensate transport direction, carrying it away from the window rather than toward it, thus resolving the contradiction between condensate removal and condensate proximity to window.
Solution Approach 2:
The gas flow is directed at different angles in different regions: away from the window in the region near the window to prevent condensate deposition, and parallel to the working plane in other regions to maintain effective condensate removal. This localized variation in flow direction optimizes both aspects of the contradiction.
2Productivity
If gas flow is directed parallel to the window surface to remove condensate, then condensate removal efficiency is improved, but condensate is entrained close to the window increasing deposition risk
Solution Approach 1:
The gas flow direction is inverted from parallel-to-surface (which causes deposition) to angled-away-from-surface (which prevents deposition). This maintains condensate removal efficiency while eliminating the harmful effect of condensate entrainment near the window, thereby preserving window clarity.
Solution Approach 2:
The gas flow system employs region-specific flow directions: angled away from the window in the window-proximal region to prevent deposition, and parallel to the working plane in the bulk chamber region to maximize removal efficiency. This localized quality variation resolves the contradiction between removal efficiency and window clarity.
3Quantity of substance
If gas nozzles are positioned to direct flow across the chamber, then condensate entrainment is improved, but uniform gas velocity across the chamber is reduced
Solution Approach 1:
The gas flow system is segmented into multiple nozzles positioned at different locations and orientations. Each nozzle contributes to a specific region of the chamber, and their combined flows create both effective condensate entrainment and relatively uniform velocity distribution across the chamber. The segmentation allows simultaneous achievement of both objectives.
Solution Approach 2:
Different regions of the chamber receive gas flow with locally optimized characteristics: near the window, flow is angled away to prevent deposition; in the bulk chamber, flow is parallel to maximize entrainment. This local quality variation enables both effective condensate entrainment and acceptable velocity uniformity.
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 significantly reduces the amount of condensate settling on the window by capturing and carrying it away, maintaining clear laser access and preventing undesirable effects.
Implementation Method 1
oriented for generating a jet of gas in the build chamber directed towards the exhaust
Implementation Method 2
arrangements that generate gas flows parallel to a window can entrain condensate carrying gas into the flow bringing the condensate in close proximity to the window
Implementation Method 3
a focussed laser beam is scanned across portions of a powder layer that correspond to a cross-section of the component being constructed such that the powder at the points where the laser scans is consolidated either by sintering or fusion
Implementation Method 4
consolidated either by sintering or fusion
Implementation Method 5
consolidated either by sintering or fusion
Implementation Method 6
significantly reduces the amount of condensate settling on the window by capturing and carrying it away
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
This invention concerns a flow device for an additive manufacturing apparatus, in which material is consolidated in a layer-by-layer manner to build a part. The flow device comprises a first member (121a, 221a) having at least one inlet aperture (113a, 213a) therein and a second member (121d, 221d) having three or more downstream apertures (113d, 213d) therein. The first and second members (113a, 13d, 213a, 213d) are connected such that the downstream apertures (113d, 213d) of the second member (121d, 221d) are in fluid communication with the inlet aperture (113a, 213a) of the first member (121a, 221a) with a shortest fluid path from the inlet aperture(113a, 213a)to each downstream aperture (113d, 213d) being substantially the same.