Laser-Welded Corner Joints for Coated Metal Window Profiles

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Solution Overview

Problem

Conventional welded corner joints in window, door, and facade constructions suffer from discoloration, unsightly weld seams, and the need for extensive recoating due to fuel-based welding processes, which complicates the coating process and increases workload.

Innovation Solution

Laser welding is used to connect coated metal profiles with minimal visible damage, forming a depression in the weld joint and allowing for a seamless coating application, eliminating the need for welding additives and reducing weld protrusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If fuel-based welding processes are used to join metal profiles, then the corner joint achieves structural strength, but the metal profiles exhibit discoloration and require extensive recoating

Engineering Contradiction:
Improvecorner joint strengthVSAvoidcoating process complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the welding process parameters by switching from fuel-based welding to laser welding, which provides controlled heat input that prevents coating discoloration and damage, thereby eliminating the need for extensive recoating while maintaining joint strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical fuel-based welding system with a laser-based welding system, which offers precise energy control and minimal heat affect zone, preserving the coating integrity and reducing post-welding treatment requirements

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If fuel-based welding processes are used to join metal profiles, then the corner joint achieves structural strength, but wide and unsightly weld seams with large protrusion are formed

Engineering Contradiction:
Improvecorner joint strengthVSAvoidweld seam appearance
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent changes the welding process parameters by using laser welding with controlled energy density, which produces narrow weld seams with minimal protrusion, improving the aesthetic appearance while maintaining adequate structural strength through optimized weld geometry

Inventive Principle:
Principle #35Parameter changes

3Shape

If sanding is performed to remove excess weld material, then the weld seam appearance is improved, but the existing coatings are completely removed requiring recoating

Engineering Contradiction:
Improveweld seam smoothnessVSAvoidrecoating workload
Core Design Contradiction:
ShapeVSLoss of time

Solution Approach 1:

The patent performs preliminary action by using laser welding parameters that prevent excessive material buildup in the first place, eliminating the need for sanding and subsequent recoating, thereby saving time and labor in the finishing process

Inventive Principle:
Principle #10Preliminary action

4Strength

If significantly protruding welds are formed in corner joints, then the corner joint achieves structural strength, but the closing of window or door is hindered and seals are excessively compressed

Engineering Contradiction:
Improvecorner joint strengthVSAvoidwindow or door closing
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the welding process parameters by using laser welding with controlled heat input and optimized weld geometry, which produces welds with minimal protrusion that do not interfere with the closing operation or cause excessive seal compression, while maintaining adequate joint strength

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

The method achieves an aesthetically appealing and dimensionally accurate corner joint with minimal effort, maintaining precise dimensional accuracy and preventing mechanical stress, while allowing for easy recoating without visible weld damage.

Implementation Method 1

Laser welding enables dimensionally accurate and targeted heat input, so that coated metal profiles can be welded with minimal visible damage to the profile, especially to the coating of the profile

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

Laser welding is performed without welding additives. Without welding filler material, no additional material is applied to the metal profiles

Methodology Applied
Scientific EffectLaser melting: Laser

Data Source

PatentEP4442950B1Window, door and/or facade structure and method for producing a corner connection of a window, door and/or facade structure
Publication Date: 2025.12.03 SCHUECO INTERNATIONAL KG
  • EP4442950B1 patent drawingFigure 1~2
  • EP4442950B1 patent drawingFigure 3~4
  • EP4442950B1 patent drawingFigure 5a~5f

AI summary

A window, door and/or facade construction comprising a corner joint (50, 60, 70) with two metal profiles (1, 2) connected to each other by one or more welded joints (6, 7, 6', 7', 10, 10', 11, 11', 33), wherein the welded joint or welded joints (6, 7, 6', 7', 10, 10', 11, 11', 31, 33) is designed as a laser-welded joint, and a method for producing a corner joint (50, 60, 70) of a window, door and/or facade construction comprising the following steps: a) providing two metal profiles (1, 2), preferably coated metal profiles, and positioning both metal profiles (1, 2) at an angle to each other;and b) welding of both metal profiles (1, 2) using a laser welding device, in particular a fiber laser welding device, wherein the power of the laser welding device is adjusted such that a weld joint (6, 7, 6' ,7', 10, 10', 11, 11', 31, 33) is provided through a profile wall or along a contact area (3) of two profile walls of the two metal profiles (1, 2).