Laser Welding Edge Geometry with Undercuts

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Solution Overview

Problem

Conventional laser beam welding requires precise alignment and pressure to prevent gaps between edges with rough surfaces, which is complex and challenging, especially at high speeds, as the small laser beam diameter can pass through gaps without melting the edge material.

Innovation Solution

The method involves creating an edge geometry with undercuts that ensure the laser beam hits the edge material, allowing for reliable welding without complex guides or pressure, by forming undercut connecting edges that overlap or interlock, ensuring the laser beam melts the material effectively and creating a stable weld.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional laser beam welding is used with small diameter laser beam, then narrow weld seam shapes can be produced, but the edges must be placed together seamlessly without gaps which requires complex guidance and alignment units

Engineering Contradiction:
Improveweld seam shape precisionVSAvoidguidance and alignment units
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The edge geometry is prepared in advance by forming undercuts on the edges to be welded. This preliminary action ensures that when the edges are placed together, the undercuts create an overlapping configuration that prevents the laser beam from passing through gaps without melting the edge material, thereby eliminating the need for complex guidance and alignment units during the welding process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The undercut geometry is applied locally at the edge regions to be welded, creating a specific local structure with overlapping surfaces. This local modification ensures that the laser beam interacts with the edge material in a controlled manner, melting it reliably even when edges are not perfectly aligned, thus reducing the need for complex alignment mechanisms.

Inventive Principle:
Principle #3Local quality

2Reliability

If pressure is applied to place edges against each other to prevent gap formation, then reliable welding can be achieved, but complex guidance or pressing elements are required

Engineering Contradiction:
Improvewelding connection reliabilityVSAvoidpressing elements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The undercut geometry is formed on the edges before welding, creating an overlapping configuration that passively prevents gap formation during welding. This preliminary structural preparation eliminates the need for pressing elements or complex guidance systems, as the undercut geometry itself ensures reliable edge contact and prevents the laser beam from passing through gaps without melting the material.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If edges with rough surfaces are welded, then material variability is accommodated, but gap formation occurs requiring complex guidance

Engineering Contradiction:
Improvesurface roughness toleranceVSAvoidguidance system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The undercut geometry is formed on the edges before welding, creating an overlapping configuration that compensates for surface roughness variations. This preliminary structural preparation ensures that even with rough surfaces, the laser beam will intersect with edge material due to the undercut overlap, preventing gap formation and eliminating the need for complex guidance systems.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The undercut geometry creates a specific local structure at the edge regions that ensures laser beam interaction with material. This local modification makes the welding process insensitive to overall edge roughness, as the undercut configuration guarantees that the laser beam will melt the edge material even when edges are not perfectly aligned, thereby accommodating material variability without complex guidance.

Inventive Principle:
Principle #3Local quality

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 ensures a secure and stable welded connection by preventing the laser beam from passing through gaps, allowing for reliable welding of edges with rough surfaces without the need for complex alignment or pressure, and enhancing the stability of the weld seam.

Implementation Method 1

the laser beams used in laser beam welding usually have a very small diameter of a few tenths of a millimeter, which results in very high energy concentrations at the welding point

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

which results in very high energy concentrations at the welding point and at the same time very narrow weld seam shapes can be produced

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2707174B1Method for welding objects with a particular edge geometry
Publication Date: 2015.08.19 PROTEKTORWERK FLORENZ MAISCH GMBH & CO KG
  • EP2707174B1 patent drawingFigure 1~8
  • EP2707174B1 patent drawingFigure 9~12

AI summary

There is described a method for welding objects (1, 2), in particular metal plates, sheets or profiles, in which at least two edges (9, 10) of the objects (1, 2) are placed against one another and the edges (9, 10) resting against one another are welded together by a laser beam. In the process, an edge geometry is created such that during the welding process the edges (9, 10) resting against one another form mutual undercuts (18, 19) in the direction of the laser beam and/or in the direction of movement of the laser beam.