Quadrupole Focus Coil Assembly for Low-Stray Electron Beam Focusing
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Solution Overview
Problem
Existing electron beam additive manufacturing systems face issues with stray magnetic fields and external interference, leading to manufacturing imperfections and increased system size due to the use of solenoid magnets, which are difficult to redesign for higher energy and are susceptible to external magnetic fields.
Innovation Solution
The implementation of a focus coil assembly with quadrupole magnets and a yoke configuration that generates a dipole magnetic field, reducing stray fields and system size, and allowing for a more compact design with shielding to protect against external interference, while enabling improved electron beam focusing and steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If solenoid magnets are used for electron beam focusing, then the system can maintain beam focus, but stray magnetic fields extend beyond the focus coil assembly causing manufacturing imperfections
Solution Approach 1:
The patent extracts the harmful stray magnetic field from the system by introducing a shielding assembly that contains and redirects the magnetic field lines. The shielding assembly includes magnetic shielding material positioned around the focus coil assembly to capture and contain the stray fields, preventing them from extending beyond the vacuum chamber and affecting manufacturing precision.
Solution Approach 2:
The patent introduces a magnetic shielding assembly as an intermediary element between the solenoid magnet and the external environment. This shielding assembly acts as a mediator that intercepts and redirects the magnetic field lines, allowing the solenoid to maintain its focusing function while preventing harmful stray fields from reaching sensitive areas.
2Manufacturing precision
If solenoid magnets are used for electron beam focusing, then beam control is achieved, but the system size increases due to the large volume required for solenoid magnets
Solution Approach 1:
The patent merges multiple functions into a single integrated assembly. The focus coil assembly is combined with the shielding assembly into one unified structure, where the shielding material is positioned around the solenoid windings. This integration eliminates the need for separate shielding components and reduces the overall system volume while maintaining both beam control and stray field containment.
Solution Approach 2:
The patent implements a nested configuration where the magnetic shielding material is positioned inside or around the solenoid magnet structure. The shielding assembly is nested within the vacuum chamber housing, and the solenoid windings are arranged around a central core, creating a compact nested arrangement that minimizes the external dimensions of the system.
3Manufacturing precision
If solenoid magnets are used for electron beam focusing, then focusing function is maintained, but the system becomes susceptible to external magnetic field interference
Solution Approach 1:
The patent converts the harmful effect of external magnetic fields into a beneficial shielding effect. The same magnetic shielding material that contains internal stray fields is also positioned to block external magnetic fields from penetrating into the vacuum chamber. The shielding assembly transforms external magnetic interference into redirected field lines that bypass the sensitive electron beam region.
4Manufacturing precision
If shielding is added to protect against stray fields, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent designs the shielding assembly to perform multiple functions simultaneously. The magnetic shielding material serves both to contain internal stray fields from the solenoid and to block external magnetic fields from entering the vacuum chamber. The shielding assembly is also structurally integrated with the vacuum chamber housing, providing both magnetic shielding and mechanical support functions in a single component.
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 significantly reduces stray fields, decreases system dimensions, enhances electron beam control, and reduces manufacturing complexity and costs by allowing for modular configurations and the use of quadrupole magnets as both focus and deflection coils, improving the overall performance and efficiency of electron beam additive manufacturing.
Implementation Method 1
The quadrupole magnet includes first, second, third, and fourth poles and a yoke... configured to generate a dipole magnetic field
Implementation Method 2
an electron beam is used as a heating source to fuse raw material... The electron beam is controlled by a focus coil assembly, which focuses the electron beam with a magnetic field
Data Source
AI summary
A system for melting, sintering, or heat treating a material is provided. The system includes a cathode, an anode, and a focus coil assembly having a quadrupole magnet. The quadrupole magnet includes four poles and a yoke. The four poles are spaced apart and surround a beam cavity. Each of the four poles includes a pole face proximate the beam cavity and an end opposite the pole face. The first and third poles are aligned along an x-axis and configured to have a first magnetic polarity at their respective pole faces and a second magnetic polarity opposite the first magnetic polarity at their respective ends. The second and fourth poles are aligned along a y-axis and configured to have the second magnetic polarity at their respective pole faces and the first magnetic polarity at their respective ends. The yoke surrounds the poles and is coupled to the poles.