Internal Laser Welding for Superconducting Cavities

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Solution Overview

Problem

Superconducting accelerator cavities face challenges in internal welding due to the risk of irregularities and increased equipment size and cost associated with external penetration welding, and existing laser welding in an argon atmosphere does not guarantee sufficient weld quality.

Innovation Solution

A welding equipment that uses a vacuum compartment, a holding member, a window member, a laser radiating member, and a mirror member to align the laser beam perpendicular to the welding groove within the annular body, allowing for precise internal laser welding and reducing equipment size and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If penetration welding from outside is employed, then welding can be performed in a vacuum atmosphere with low contamination, but unexpected irregularities are formed inside the superconducting accelerator cavity and post-processing is time consuming

Engineering Contradiction:
Improveweld qualityVSAvoidpost-processing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Instead of welding from the outside of the vacuum container, the invention inverts the approach by performing laser welding from the inside of the superconducting accelerator cavity. The laser beam is introduced through a window member on the vacuum container wall, allowing the laser source to be positioned outside the vacuum while the welding operation occurs inside the cavity. This inversion eliminates the need for post-processing irregularities while maintaining vacuum atmosphere benefits

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If penetration welding from outside is employed, then welding can be performed in a vacuum atmosphere, but the volume of vacuum container is increased which increases equipment size and cost

Engineering Contradiction:
Improveweld qualityVSAvoidvacuum container volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The invention extracts the laser beam source from the vacuum container interior and positions it outside through a window member. This allows the welding operation to occur inside the vacuum atmosphere while the bulky laser equipment remains outside, thereby maintaining a compact vacuum container volume and reducing equipment size and cost

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If penetration welding from outside is employed, then welding can be performed in a vacuum atmosphere, but it takes time to establish the vacuum atmosphere which increases operation time and operating costs

Engineering Contradiction:
Improveweld qualityVSAvoidvacuum establishment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

By extracting the laser source from the vacuum interior and positioning it outside through a window member, the vacuum container volume is minimized. This reduction in volume directly decreases the time required to establish and maintain the vacuum atmosphere, thereby reducing operation time and operating costs while still enabling welding in a controlled vacuum environment

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of manufacture

If laser beam is incident from outside the vacuum container, then welding can be performed inside the superconducting accelerator cavity, but the laser beam is incident at an angle with respect to the welding groove which causes risk of missing the welding groove and insufficient welding properties

Engineering Contradiction:
Improvewelding accessibilityVSAvoidwelding groove accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention introduces a mirror member as an intermediary optical element positioned inside the vacuum container. The laser beam is directed at the mirror member at an angle, and the mirror reflects the beam perpendicular to the welding groove surface. This intermediary mechanism enables both easy accessibility (laser from outside) and high precision (perpendicular incidence on groove), solving the contradiction between manufacturing ease and welding accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances weld quality by ensuring precise alignment of the laser beam, reduces internal irregularities, and minimizes equipment size and operating costs by establishing a vacuum atmosphere efficiently.

Implementation Method 1

a laser radiating member that is installed outside the vacuum compartment and that radiates a laser beam into an internal space of the annular joined body through the window member

Methodology Applied
Scientific EffectLaser beam: Laser

Implementation Method 2

forms an annular joined body by joining the corresponding openings with each other by laser welding

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 3

a mirror member that is installed so as to be positioned in the internal space of the annular joined body and that adjusts a reflected laser beam, formed by reflecting the laser beam, so as to be oriented in a direction perpendicular to the welding groove

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 4

a vacuum compartment in which a vacuum atmosphere can be established

Methodology Applied
Scientific EffectVacuum atmosphere: Vacuum

Data Source

PatentEP2570224B1Welding equipment
Publication Date: 2020.03.11 MITSUBISHI HEAVY IND MACHINERY SYST LTD
  • EP2570224B1 patent drawingFigure 1
  • EP2570224B1 patent drawingFigure 2
  • EP2570224B1 patent drawingFigure 3~4

AI summary

Provided is a welding equipment that performs welding of an annular body from an inside thereof so as to be perpendicular to a welding groove, thus making it possible to enhance the weld quality. A welding equipment (1) that forms an end part (5) includes a vacuum chamber (23) in which a vacuum atmosphere can be established; a holding member (25) that is installed in the vacuum chamber (23) and that holds the end part (5) in which a welding groove is formed by placing a half cell (11), an end plate (17), and a beam pipe (19) next to each other; a window (29) that is installed in a top-end surface portion (27) of the vacuum chamber (23), which intersects with an axial center (0) of the end part (5), and that forms a portion thereof; a laser radiating head (35) that is installed outside the vacuum chamber (23) and that radiates a laser beam (33) into an internal space of the end part (5) through the window (29); and a mirror member (37) that is installed in the internal space of the end part (5) and that adjusts a reflected laser beam (55), formed by reflecting the laser beam (33), so as to be oriented in a direction perpendicular to the welding groove.