Reconfigurable Electron Gun for Variable Melt Pool Control
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Solution Overview
Problem
Existing electron guns for additive manufacturing, such as EB-PBF, have a fixed cathode and bias cup configuration, limiting the ability to alter the size and shape of the melt pool, as the electron beam properties are constant.
Innovation Solution
The electron gun features a moving cathode and anode station with multiple cathode and bias cup pairs, allowing for the production of electron beams with varying sizes and properties. A controller synchronizes the movement of the cathode and anode stations to control the electron beam size and parameters. Additionally, a Cartesian deflection coil system adjusts the electron beam position on the sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed cathode and bias cup configuration is used, then the electron beam properties remain constant and reliable, but the ability to alter melt pool size and shape is limited
Solution Approach 1:
The electron gun is divided into multiple independent cathode-bias cup-anode assemblies, each capable of generating electron beams with different properties. This segmentation allows selective activation of specific assemblies to produce varied melt pool characteristics without requiring complete redesign of the electron gun system.
Solution Approach 2:
The electron gun system transitions from a static fixed configuration to a dynamic reconfigurable system where different cathode-bias cup-anode assemblies can be selectively activated. This dynamic capability enables real-time adjustment of electron beam properties to alter melt pool size and shape during the additive manufacturing process.
2Adaptability or versatility
If multiple cathode and bias cup pairs are introduced, then electron beam size and parameters can be varied, but the device complexity increases
Solution Approach 1:
Each cathode-bias cup-anode assembly is designed as a universal module that can function independently to produce electron beams with specific characteristics. These multi-functional modules can be selectively activated based on the desired melt pool properties, reducing the need for entirely separate systems for different beam configurations.
Solution Approach 2:
The system controls electron beam size and parameters by selecting and activating specific cathode-bias cup-anode assemblies with predetermined geometric configurations. This parameter change approach allows varied electron beam properties to be achieved through selective module activation rather than continuous adjustment mechanisms.
3Manufacturing precision
If a single set of cathode and bias cup is used, then the device structure remains simple, but the melt pool shape and aspect ratio cannot be altered
Solution Approach 1:
The electron gun is segmented into multiple independent cathode-bias cup-anode assemblies, each optimized for producing electron beams with specific characteristics. This segmentation enables precise control over melt pool shape and aspect ratio by selecting the appropriate assembly for each manufacturing requirement.
Solution Approach 2:
Each cathode-bias cup-anode assembly is designed with specific local geometric qualities tailored to produce electron beams with particular properties. This local quality differentiation allows precise control of melt pool characteristics by activating the assembly with the appropriate local configuration for each desired outcome.
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 configuration enables the generation of electron beams with customizable sizes and parameters, allowing for the creation of melt pools with varying dimensions, thereby enhancing the flexibility and precision of the additive manufacturing process.
Implementation Method 1
Each of the plurality of cathodes is heated by a heating power supply such that it emits thermal electrons from its tip
Implementation Method 2
The negative potential of the bias cup generates an electric field around the cathode and reduces the size of the cathode electron emission opening, thereby reducing the number of electrons passing through
Implementation Method 3
an anode configured to emit and accelerated thermal electrons along the beam column
Implementation Method 4
a focus coil configured to focus the electron beam to a predetermined size using an electromagnetic force
Implementation Method 5
When the deflection coil is excited it generates electromagnetic force that is applied to the electron beam to adjust a position of the electron beam when impinging on a sample
Data Source
AI summary
Examples of an electron gun with a moving cathode station and a moving anode station are described. The moving cathode has a driver that moves the station and comprises a plurality of cathodes with a plurality of bias cups to control a thermal electron emission region by applying a bias voltage to the bias cup. The moving anode station comprises a plurality of anodes and has driver to move the anode station such that a position of each anode is synchronized with a positioned of a respective matching pair of cathode and bias cup. A controller that is in communication with the anode and cathode moving stations controls the bias voltage and the drivers to control the amount of thermal electrons and to synchronize and align a predetermined cathode with a predetermined anode thus controlling the size and parameters of the generated electron beam.