Gap-Free Metal Jointing with Laser-Defined Brazing Recesses

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Solution Overview

Problem

Existing methods for joining metallic components, such as laser welding, ultrasonic welding, resistance welding, and brazing, fail to achieve a consistently high-quality, gap-free, and force-fit connection due to metallurgical changes, undefined gaps, or complex processes, limiting strength and temperature performance.

Innovation Solution

A method combining laser-assisted engraving and ohmic heating to create precise recesses in the components, followed by the application of a brazing alloy, ensuring controlled heat distribution and defined contact areas through grooves and ridges, allowing for a force-fit, gas-tight connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If laser welding is used to create a force-fit connection, then the connection strength is improved, but metallurgical changes occur in the base material due to high temperature input

Engineering Contradiction:
Improveconnection strengthVSAvoidmetallurgical stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The invention changes the thermal parameters by using a brazing alloy with a melting point significantly lower than the base material (e.g., silver brazing alloy melting at 700-900°C for steel components). This allows the joining process to occur at temperatures that do not cause metallurgical changes in the base material, while still achieving strong connections through the brazing alloy's metallurgical bonding properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The brazing alloy serves as an intermediary material between the two base materials being joined. It melts at a lower temperature, flows into the gap between components, and creates metallurgical bonds with both surfaces, thereby achieving strong connections without subjecting the base materials to high-temperature laser welding that would cause unwanted metallurgical changes

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If brazing is used to join components, then flexibility and joint strength are improved, but an undefined gap remains between the components

Engineering Contradiction:
Improvejoint strengthVSAvoidgap definition
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The invention performs preliminary action by creating precisely defined gaps between components before the brazing process. These gaps are designed with specific dimensions and geometries that control the flow and distribution of the brazing alloy, ensuring complete filling without excess material and achieving both strong joints and precise dimensional control

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention applies local quality by creating non-uniform gap geometries in specific areas. The gap width and depth are locally optimized to control brazing alloy flow patterns, ensuring proper filling in critical areas while maintaining precise dimensional control. This allows different regions to have different gap characteristics tailored to their specific joining requirements

Inventive Principle:
Principle #3Local quality

3Productivity

If resistance welding is used to melt base materials, then connection speed is improved, but very high temperature input causes metallurgical and mechanical changes

Engineering Contradiction:
Improveconnection speedVSAvoidmaterial composition stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The invention changes the temperature parameter by using brazing processes that operate at temperatures well below the melting point of the base materials. This allows rapid joining similar to resistance welding while avoiding the metallurgical and mechanical changes caused by extreme heat input, maintaining material properties in the base components

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If soft soldering is used with tin-containing solder, then ease of operation is improved, but strength and service temperature are reduced

Engineering Contradiction:
Improvesoldering easeVSAvoidjoint strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The invention changes the material parameter by replacing tin-containing soft solder with brazing alloys that have higher melting points and superior mechanical properties. The brazing alloys maintain ease of operation through controlled melting and flow characteristics while providing significantly higher joint strength and temperature resistance compared to traditional soft soldering materials

Inventive Principle:
Principle #35Parameter changes

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

Achieves a mechanically strong, tightly toleranced, and chemically resistant connection without deformation, with reproducible quality and defined contact surfaces, enhancing joint durability and strength.

Implementation Method 1

In a first process step, the soldering zones on the metal surfaces to be joined are processed, in particular by ablation with a laser beam

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

the brazing component is brought into a molten state by Joule heating through an electrical current

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

the molten brazing alloy is distributed in the recesses formed in the area of the soldering zones

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP4168204B1Method for producing a gap-free and force-fitting connection
Publication Date: 2026.03.25 STRUNK CONNECT AUTOMATED SOLUTIONS GMBH & CO KG
  • EP4168204B1 patent drawingFigure 1~2
  • EP4168204B1 patent drawingFigure 3~5
  • EP4168204B1 patent drawingFigure 6~9

AI summary

The invention relates to a method for producing a gap-free and non-positive connection between at least three metallic individual components (2).