Laser Weld Gap Geometry for Deep Oxidation-Free Component Joining

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing laser welding techniques, particularly deep welding, face challenges such as oxidation of sensitive materials, formation of oxide layers leading to weak welds, and difficulty in welding components with different materials or under high pressure, resulting in unstable and aesthetically impaired welds.

Innovation Solution

A procedure for laser welding that involves arranging components with a radiation area having a gap with rounded walls, allowing the laser beam to penetrate and melt the material within the gap, which then flows to fill the gap from below, thereby controlling the weld seam geometry and depth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If deep penetration welding regime is used to achieve deep weld seams, then weld depth is improved, but oxidation of sensitive materials occurs leading to embrittlement and weak welds

Engineering Contradiction:
Improveweld depthVSAvoidweld strength
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent applies the inert atmosphere principle by creating a protective gas environment (argon or nitrogen) over the weld pool and irradiation area. This prevents oxidation of sensitive materials during laser welding while maintaining deep penetration welding conditions, thereby resolving the contradiction between achieving deep welds and preventing oxidation-induced embrittlement

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent implements local quality by applying protective gas specifically to the irradiation area and weld pool region where oxidation occurs, rather than protecting the entire workpiece. This targeted approach prevents oxidation at the critical welding zone while maintaining the deep penetration welding process

Inventive Principle:
Principle #3Local quality

2Length of stationary object

If deep penetration welding regime is used to achieve deep weld seams, then weld depth is improved, but spatter and pores form preventing smooth weld formation

Engineering Contradiction:
Improveweld depthVSAvoidweld surface quality
Core Design Contradiction:
Length of stationary objectVSManufacturing precision

Solution Approach 1:

The protective gas atmosphere suppresses spatter formation and prevents pore formation by displacing oxygen and other reactive gases from the weld pool area. This allows deep penetration welding to proceed while maintaining smooth weld surface quality free from spatter and porosity defects

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The protective gas acts as an intermediary substance between the laser beam/weld pool and the surrounding atmosphere. It mediates the welding process by preventing harmful interactions (oxidation, spatter, pore formation) while allowing the deep penetration welding to occur, thus resolving the contradiction between depth and surface quality

Inventive Principle:
Principle #24Intermediary (Mediator)

3Length of stationary object

If deep penetration welding regime is used to achieve deep weld seams, then weld depth is improved, but metal vapor precipitates causing aesthetic impairment and electrical issues

Engineering Contradiction:
Improveweld depthVSAvoidmetal vapor precipitation
Core Design Contradiction:
Length of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The inert gas atmosphere prevents metal vapor from reacting with oxygen to form oxides that precipitate on the weld surface. By maintaining an oxygen-free environment, the patent eliminates aesthetic impairment from oxide precipitation and prevents electrical issues from metal vapor deposition, while preserving deep weld penetration

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

4Reliability

If heat conduction welding regime is used to avoid oxidation, then weld quality is improved, but weld depth is insufficient for stable high-pressure connections

Engineering Contradiction:
Improveweld qualityVSAvoidweld depth
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent combines the advantages of both welding regimes by using protective gas to prevent oxidation (quality improvement) while employing laser parameters that achieve deep penetration (depth improvement). The inert atmosphere enables the use of higher power densities without oxidation damage, thus achieving both high weld quality and sufficient depth for pressure-tight connections

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

5Length of stationary object

If oxidation-sensitive materials are welded with high laser power to achieve deep seams, then weld depth is improved, but gas-tight welds become impossible due to seam embrittlement

Engineering Contradiction:
Improveweld depthVSAvoidgas-tightness
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The protective gas atmosphere is essential for achieving gas-tight welds in oxidation-sensitive materials. By preventing oxidation during deep penetration welding, the patent eliminates seam embrittlement while maintaining deep weld seams, thus simultaneously achieving both depth and gas-tightness requirements

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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 enables the formation of stable, deep, and wide weld seams with controlled geometry, avoiding oxidation and ensuring strong, gas-tight connections without additional materials or protective gases, suitable for thin-walled and sintered components.

Implementation Method 1

The irradiation surface is irradiated with a laser beam along an irradiation direction in a joining region

Methodology Applied
Scientific EffectLaser radiation: Laser

Implementation Method 2

The first component and the second component are joined to one another by thermal conduction welding

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The laser radiation melts material from the gap walls—particularly by creating multiple reflections of the laser radiation in the gap

Methodology Applied
Scientific EffectMultiple reflections: Reflection

Implementation Method 4

This material then flows into the tapered gap and essentially fills the gap from below, i.e., from the side of the gap facing away from the irradiation area

Methodology Applied
Scientific EffectMaterial flow:

Implementation Method 5

the irradiation surface in the joining region has a gap which tapers in the irradiation direction starting from the irradiation surface

Methodology Applied
Scientific EffectGeometric constraint: Geometry

Data Source

PatentEP3755492B1Method for joining two components to one another by means of laser welding
Publication Date: 2025.04.16 WLLT GMBH
  • EP3755492B1 patent drawingFigure 1
  • EP3755492B1 patent drawingFigure 2
  • EP3755492B1 patent drawingFigure 3

AI summary

The invention relates to a method for joining two components (1, 3) to one another by laser welding, wherein a first component (1) and a second component (3) are arranged adjacent to one another to form a component arrangement (5), in that the component arrangement (5) has an irradiation surface (7) which has a first radiation partial surface (7.1) on the first component (1) and a second radiation partial surface (7.2) on the second component (3), wherein the irradiation surface (7) is irradiated with a laser beam (11) along an irradiation direction in a joining region (9). The method is characterized in that the irradiation surface (7) has a gap (15) in the joining region (9), said gap extending from the irradiation surface (7) in the irradiation direction, wherein the first component (1) and the second component (3) are joined to one another by heat conduction welding.