Laser Butt Welding Groove for Variable-Thickness Joints

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Solution Overview

Problem

Existing butt welding methods struggle to effectively join components with varying thicknesses at different joint positions, as changing welding conditions based on thickness and shape is difficult, especially when using a laser beam as a heat source.

Innovation Solution

A joint method involving a first member with a substrate and projection, and a second member with a substrate and projection, where inclined surfaces are formed to accommodate a laser torch, allowing for butt welding with a high-density energy source and subsequent buildup welding using a metal deposition-type device, enabling the joining of components with varying thicknesses without complex adjustments in welding conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If butt welding is used to join components with varying thicknesses, then welding speed and laser output need to be continuously changed to accommodate thickness variations, but this is difficult to implement in practice

Engineering Contradiction:
Improveadaptability to thickness variationsVSAvoidcomplexity of welding condition control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The groove is formed in advance on the component surface before welding, creating a predetermined geometric structure that accommodates thickness variations. This preliminary action eliminates the need for real-time welding parameter adjustments, as the groove geometry is designed to match the laser torch configuration and welding process requirements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the geometric parameters of the component (creating grooves with specific inclination angles and dimensions) to adapt to thickness variations. By modifying the component geometry rather than welding parameters, the system achieves adaptability to different thicknesses while maintaining fixed welding conditions.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If welding conditions are changed to match thickness variations, then welding quality improves, but the ease of operation decreases due to difficulty in continuously adjusting conditions

Engineering Contradiction:
Improvewelding qualityVSAvoidease of welding operation
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The groove is prepared beforehand with precise geometric parameters that ensure high welding quality. This preliminary preparation eliminates the need for operators to continuously adjust welding conditions during the process, thereby maintaining both high manufacturing precision and ease of operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The groove geometry is designed to self-accommodate thickness variations, meaning the groove structure itself adapts to different component thicknesses without requiring external control adjustments. The groove's inclination angle and dimensions are configured to automatically match the welding process requirements for various thicknesses.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If laser torch is positioned close to the joint for precise welding, then welding precision improves, but the laser torch may contact the inclined surfaces causing interference

Engineering Contradiction:
Improvewelding precisionVSAvoidinterference between laser torch and joint surfaces
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The groove is designed with different geometric characteristics at different locations: the inclined surfaces provide a gradual approach for the laser torch, while the bottom region provides sufficient clearance. This local differentiation of groove geometry allows the laser torch to be positioned close to the joint for precision welding while preventing contact with the inclined surfaces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The solution moves the clearance provision from the horizontal dimension (laser torch to joint distance) to the vertical dimension (groove depth and inclination). By creating a three-dimensional groove structure with inclined surfaces, the invention provides clearance in the vertical direction while maintaining close proximity in the horizontal direction, thus achieving both precision and avoiding interference.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 method expands the application range for joining components with varying thicknesses by allowing for successful welding without the need for frequent changes in welding conditions, even when thickness differences are significant, and avoids interference between the welding device and the joint targets.

Implementation Method 1

The butt welding may be executed by use of a first welding device using high-density energy as a heat source

Methodology Applied
Scientific EffectHigh-density energy:

Implementation Method 2

The buildup welding may be executed by use of a metal deposition-type second welding device using a laser beam as a heat source

Methodology Applied
Scientific EffectLaser beam: Laser

Data Source

PatentEP3871828B1Joining method
Publication Date: 2024.08.21 IHI CORP
  • EP3871828B1 patent drawingFigure 1
  • EP3871828B1 patent drawingFigure 2
  • EP3871828B1 patent drawingFigure 3~3(b)

AI summary

A joint method of bringing a first member (10) into contact with a second member (20) to be joined to each other, includes a groove formation step of removing part of a first projection (12) opposed to a second projection (22) and part of the second projection (22) opposed to the first projection (12) to form a groove region (Rg) between the first projection (12) and the second projection (22), a first welding step of joining the first member (10) and the second member (20) to each other by butt welding, and a second welding step of filling the groove region (Rg) by buildup welding. The groove formation step forms a first inclined surface (12d) in the first projection (12) facing the groove region (Rg) to be gradually distant from a joint position joined with the second projection (22) so as to be closer to an outer surface of the first projection (12), and forms a second inclined surface (22d) in the second projection (22) facing the groove region (Rg) to be gradually distant from the joint position joined with the first projection (12) so as to be closer to an outer surface of the second projection (22).