Pedestal Geometry for Powder Evacuation in Additive Manufacturing
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Solution Overview
Problem
Additive layer manufacturing (ALM) methods face challenges in removing excess powder from components with complex geometries, particularly when pedestals coincide with cavity walls, leading to powder entrapment and altered design integrity, which is detrimental in high-temperature and pressure environments like gas turbine engines.
Innovation Solution
Modifying the geometry of pedestals to intersect with passage walls at obtuse angles instead of acute angles, allowing excess powder to slide down and be removed effectively, while maintaining the optimal number and position of pedestals for cooling purposes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pedestals coincide with cavity walls to maximize cooling surface area, then cooling efficiency is improved, but powder entrapment occurs at acute angle intersections leading to manufacturing defects
Solution Approach 1:
The pedestal geometry is modified locally at the intersection region with the cavity wall. Instead of uniform cylindrical pedestals, the design incorporates tapered or chamfered edges where the pedestal meets the wall, creating an obtuse angle that prevents powder entrapment while maintaining the pedestal's cooling function in its main body.
Solution Approach 2:
Rather than accepting the acute angle intersection that naturally forms when pedestals coincide with walls, the invention inverts the approach by designing the pedestal-wall intersection to create an obtuse angle. This reverses the geometric relationship that causes powder trapping, allowing powder to escape along the wall surface rather than becoming trapped in sharp corners.
2Ease of manufacture
If pedestal geometry is simplified to facilitate powder removal, then manufacturing ease is improved, but cooling efficiency is reduced due to fewer or repositioned pedestals
Solution Approach 1:
The solution applies local geometric modification only at the critical intersection zones where pedestals meet the cavity wall, while preserving the full pedestal structure and arrangement in the bulk of the component. This localized approach maintains cooling efficiency without requiring global simplification of the pedestal geometry.
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
Ensures complete evacuation of excess powder without compromising the cooling efficiency or design integrity of components, reducing the risk of powder entrapment and subsequent performance issues in gas turbine engines.
Implementation Method 1
the treatment involves local heating using a laser or electron beam
Implementation Method 2
laser sintering, laser melting and electron beam melting (EBM)
Implementation Method 3
the treatment involves local heating using a laser or electron beam
Implementation Method 4
laser sintering, laser melting and electron beam melting (EBM)
Implementation Method 5
Excess powder is typically removed by turning the component such that a passage outlet faces downwards and then shaking, vibrating, patting or otherwise agitating the component
Data Source
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AI summary
A method for the manufacture of a component having an internal cavity (41) and an array of pedestals (43, 44) extending into the cavity comprises; defining an external geometry of the component, defining a core geometry of the component; using a powder bed additive layer manufacturing method, building the component from a plurality of layers laid on a first plane; and removing excess powder from the core in a first powder extraction direction along the first plane. The core geometry is adapted for improved powder removal. The core geometry includes a main core passage (41), an array of pedestals (43, 44) extending into the passage from the first plane and a passage wall (42) extending from the first plane, one or more pedestals (44) coinciding with the passage wall (42), the coinciding pedestals (44) having a cross section in a plane parallel to the first plane which is altered with respect to the cross-section of non-coinciding pedestals (43) to extend a face (47) of the pedestal (44) which faces away from the powder extraction direction (A) so as to intersect the passage wall (42) at an obtuse angle (45).