Additive Manufacturing Support Pins for Electron Beam Melting
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Solution Overview
Problem
In additive layer manufacturing (ALM) via Electron Beam Melting, unsupported downwardly facing surfaces in three-dimensional products can lead to localized overheating, poor surface finish, distortion, and increased manufacturing costs due to wastage of expensive metal powder, as existing support structures like wafers can trap powder and are difficult to remove and recycle efficiently.
Innovation Solution
The method involves forming support pins within the powder bed using an electron beam to provide structural support to downwardly facing surfaces, which are spaced apart and extend from the surface, allowing for efficient powder recycling and easier removal during finishing processes, reducing distortion and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wafer support structures are used to support downwardly facing surfaces, then distortion and overheating are prevented, but powder is trapped in lattice spaces making removal difficult and increasing manufacturing cost
Solution Approach 1:
The support structure is segmented into discrete support pins rather than continuous wafer structures. Each pin is a separate element that can be independently removed, eliminating the problem of trapped powder in lattice spaces while maintaining the necessary support function during manufacturing
Solution Approach 2:
The support structures are designed as temporary elements that are extracted (removed) after the main manufacturing process is complete. The support pins are intentionally created, serve their support function during layer deposition, and then removed in a finishing operation, leaving no trapped powder issue
2Manufacturing precision
If wafer support structures are used to prevent localized overheating, then surface finish improves, but manufacturing cost increases due to powder wastage
Solution Approach 1:
Instead of using extensive wafer structures that cover large areas and trap significant powder, the support function is provided locally at discrete pin locations. This localized approach maintains surface finish quality where needed while minimizing the total volume of support material and associated powder wastage
Solution Approach 2:
The support pins are designed to be removed and the metal material recovered for reuse. By using removable support structures rather than permanent lattice wafers, the system enables recovery of the support material, reducing overall metal powder wastage and manufacturing cost
3Reliability
If thick first layer is used to prevent electron beam melt-through, then work platform is protected, but product height increases reducing manufacturing efficiency
Solution Approach 1:
A thick initial layer is deposited as a preliminary protective action before actual product manufacturing begins. This first layer serves its protective function and is then removed, allowing subsequent layers to be deposited at optimal thicknesses that maximize manufacturing efficiency without compromising platform protection
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 powder wastage, enhances surface finish quality, and simplifies the removal of support structures, improving manufacturing efficiency and reducing the overall footprint of the supported component.
Implementation Method 1
When the electron beam 9 impinges on the top layer of powder within the powder bed 7, the kinetic energy of the electrons is transformed into heat which melts the powder to form the respective cross-section of the product 2.
Data Source
Figure 1
Figure 2~5
Figure 6~8
AI summary
There is proposed an additive layer manufacturing (ALM) method for the production of a three-dimensional product (20) via successive fusion of parts of a powder bed (25), said parts corresponding to successive cross-sections of the product (20). The method comprises the steps of: a) laying down a powder layer (24) on said powder bed (25), and b) focussing energy (9) on a predetermined area (26) of said powder layer to fuse said area (26) of the powder layer and thereby form a cross-section of the product (20); wherein steps a) and b) are repeated to form successive cross-sections of the product (20), and wherein at least one of said steps b) involves focussing said energy (9) on an area (26) of the respective powder layer which is at least partially unsupported by a previously formed cross-section of the product (20) to thereby form a downwardly facing surface (21) of the product. The method is characterised in that at least some of said successive steps b) involve focussing energy (9) on a support area (27) of the respective powder layer, to fuse the support area (27) and thereby form successive cross-sections of a support pin (22) within the powder bed (25), the support pin (22) extending outwardly from the downwardly facing surface (21) of the product when it is formed, so as to support the downwardly facing surface (21).