Dual-Deflector Electron Beam Steering for Additive Manufacturing
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Solution Overview
Problem
Current additive layer manufacturing techniques using electron beams are inefficient in scanning patterns, leading to wasted energy and defects due to the need for high-speed beam deflection between melt pools and slow scanning within pools, requiring complex geometry-dependent scan strategies and bespoke patterns for each product.
Innovation Solution
The method employs a dual-deflector system with a long-range deflector for initial positioning and a short-range deflector for precise scanning, allowing faster scan rates and uniform thermal distribution by separating beam steering into long-range and short-range movements, enabling the creation of 'area scanners' that mimic a single beam with specific shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single electromagnetic deflector is used to scan the electron beam across the powder bed, then the beam can be steered to form layers, but the system requires complex geometry-dependent scan patterns and wastes energy during transit between melt pools
Solution Approach 1:
The patent divides the single deflector function into two separate deflectors: a first deflector for long-range beam positioning between melt pools and a second deflector for short-range scanning within melt pools. This segmentation allows each deflector to be optimized for its specific function, reducing unnecessary beam movement and energy waste during transit between processing locations.
2Manufacturing precision
If the electron beam is scanned continuously within a melt pool, then uniform melting is achieved, but the beam must be deflected rapidly between melt pools requiring high deflection speeds
Solution Approach 1:
The patent separates the scanning function into two distinct deflectors with different speed requirements. The first deflector handles slow, long-range positioning between melt pools, while the second deflector handles fast, short-range scanning within melt pools. This segmentation allows the system to maintain continuous scanning for uniform melting while reducing the maximum deflection speed requirements for the positioning system.
3Loss of time
If high deflection speeds are used to move the beam between melt pools, then positioning time is reduced, but the scanning precision within melt pools deteriorates
Solution Approach 1:
The patent assigns different speed characteristics to the two deflectors based on their functions. The first deflector is optimized for slower, more precise long-range positioning between melt pools, while the second deflector is optimized for faster scanning within melt pools. This segmentation allows the system to achieve both rapid repositioning and precise scanning without compromising either performance metric.
4Productivity
If complex geometry-dependent scan patterns are developed for each product, then the electron beam can efficiently trace the desired shape, but the system requires bespoke patterns for every product increasing complexity
Solution Approach 1:
The patent creates a universal two-deflector scanning system that can efficiently handle various geometries without requiring bespoke scan patterns for each product. The first deflector positions the beam for any location on the powder bed, while the second deflector performs the actual melting scan. This universal configuration maintains scan efficiency across different product geometries while reducing the need for complex, product-specific pattern development.
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 energy wastage and ensures uniform melting by maintaining continuous temperature increase at scan locations, improving the precision and efficiency of the additive layer manufacturing process.
Implementation Method 1
As the electron beam is scanned over the powder bed, energy is deposited into the powder, raising its temperature
Implementation Method 2
Such electron beam sources are controlled using electric and/or magnetic fields to steer or condition the electron beam. These electromagnetic deflectors allow the electron beam to be scanned across the substrate medium
Data Source
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AI summary
A method of forming a product using additive layer manufacture is provided. The method comprises forming the product as a series of layers, each layer being formed by fusing powder deposited as a powder bed by scanning the powder bed using a charged particle beam to form a desired layer shape. For each layer, the powder is fused by melting successive areas of the powder bed by scanning the charged particle beam using a combination of a relatively long-range deflector and a relatively short-range deflector, wherein the relatively long-range deflector deflects the charged particle beam over a larger deflection angle than the short-range deflector. Also provided are a corresponding charged particle optical assembly, and an additive layer manufacturing apparatus.