Laser Weld Fault Monitoring via CNN Height Profile Reconstruction

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Solution Overview

Problem

Current fault monitoring systems for laser welding processes are inefficient due to the need for time-consuming 3D scans and inaccurate analysis of weld seam quality using two-dimensional greyscale images, which complicates integration into ongoing manufacturing processes.

Innovation Solution

A system utilizing a convolutional neural network to generate a height profile from two-dimensional image data, allowing for rapid and accurate fault monitoring without the need for continuous 3D scans, using a camera aligned coaxially with the laser processing head and optionally an OCT scanner for training data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If 3D scans are used for weld seam quality monitoring, then measurement precision is improved, but recording time increases and integration into ongoing manufacturing processes becomes difficult

Engineering Contradiction:
Improveweld seam quality assessment accuracyVSAvoidrecording time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent uses a camera to capture two-dimensional images of the weld seam, creating a visual copy that serves as the basis for height profile reconstruction through neural network processing. This copying approach replaces time-consuming 3D scanning while maintaining sufficient measurement precision for quality control applications.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical 3D scanning system with an optical imaging system (camera) combined with computational processing using a convolutional neural network. This substitution eliminates the need for physical 3D measurement apparatus while achieving comparable height profile accuracy through image-based reconstruction.

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

2Loss of time

If two-dimensional greyscale images are used for weld seam analysis, then recording time is reduced, but height structure analysis accuracy deteriorates

Engineering Contradiction:
Improveevaluation timeVSAvoidheight structure analysis accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent transforms two-dimensional image data into three-dimensional height profile information through neural network processing. The convolutional neural network learns to predict height values from 2D grayscale intensity patterns, effectively adding the third dimension (height) to the analysis without requiring 3D scanning hardware or increased recording time.

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

Solution Approach 2:

The convolutional neural network serves as an intermediary that bridges the gap between 2D image data and 3D height profile information. The network learns the complex mapping relationship between grayscale intensity patterns and surface height, enabling accurate height structure analysis from 2D images without direct 3D measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If complex systems with multiple cameras and 3D scanners are used, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveheight profile accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes a single camera perform multiple functions: capturing weld seam images, providing training data for the neural network, and serving as the basis for height profile reconstruction. This multi-functionality eliminates the need for separate 3D scanners, multiple cameras, and complex synchronization systems while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the approach from direct physical measurement (3D scanning) to computational inference (neural network prediction). By transforming the measurement paradigm from hardware-based to software-based, the system achieves comparable accuracy with significantly reduced device complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20250100072A1System and method for the fault monitoring of laser welding processes
Publication Date: 2025.03.27 TRUMPF LASER GMBH CO KG
  • US20250100072A1 patent drawing
  • US20250100072A1 patent drawing

AI summary

A system for fault monitoring of laser welding processes on a component that is to be processed or has been processed by a laser processing apparatus includes an image recording device for creating two-dimensional image data of the component, and an evaluation unit configured to, based on the two-dimensional image data created by the image recording device, determine associated height values and create a height profile of the component by using a convolutional neural network.