Laser Weld Feedback Control Using Return-Light Waveforms

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Solution Overview

Problem

Existing laser welding systems struggle to maintain weld quality due to various fluctuation factors, including weld width and depth, beyond focal position shifts, leading to issues such as spattering and inconsistent weld quality.

Innovation Solution

A laser processing system that utilizes a light detector to capture return light from the workpiece, generates waveform data, extracts feature values from this data to identify processing abnormalities, and adjusts parameters like laser focal position, energy distribution, and scanning speed to stabilize weld quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If focal position correction is implemented, then weld quality stability is improved, but other fluctuation factors such as weld width and depth are not addressed

Engineering Contradiction:
Improveweld quality stabilityVSAvoidcomprehensive parameter adjustment capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system implements real-time feedback by detecting return light during laser processing, generating waveform data, and comparing it against reference values. When deviations are detected in parameters such as weld width, depth, or focal position, the system automatically adjusts processing parameters to maintain weld quality within specified ranges, creating a closed-loop control system that addresses multiple fluctuation factors simultaneously

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts multiple processing parameters including laser output power, focal position, and scanning speed based on detected waveform deviations. By changing these parameters in real-time according to actual processing conditions, the system compensates for various fluctuation factors affecting weld quality, not just focal position alone

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If multiple processing parameters are adjusted in real-time, then weld quality is maintained, but system complexity increases

Engineering Contradiction:
Improveweld quality consistencyVSAvoidparameter control system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system performs self-diagnosis and self-correction by automatically detecting waveform deviations and adjusting processing parameters without external intervention. The control unit compares real-time waveform data against reference values and autonomously determines necessary parameter adjustments, enabling the system to maintain weld quality through self-regulation rather than requiring complex external control mechanisms

Inventive Principle:
Principle #25Self-service

3Reliability

If waveform data analysis is performed in real-time, then processing abnormalities are detected, but processing time is increased

Engineering Contradiction:
Improveabnormality detection accuracyVSAvoidprocessing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary analysis by comparing real-time waveform data against pre-established reference values and predetermined ranges. By having reference standards prepared in advance and using efficient comparison algorithms, the system can quickly identify deviations without performing complex real-time calculations, thus maintaining high detection accuracy while minimizing additional processing time

Inventive Principle:
Principle #10Preliminary action

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 system effectively maintains consistent weld quality by dynamically adjusting parameters in response to fluctuations, reducing defects like spattering and improving overall processing precision.

Implementation Method 1

a light detector that detects return light including at least one of thermal radiation, visible light, or reflected light

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

return light including at least one of thermal radiation, visible light, or reflected light

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a laser processing device that irradiates a workpiece with laser light

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 4

irradiates a workpiece with laser light

Methodology Applied
Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Data Source

PatentEP4725637A1Laser processing system
Publication Date: 2026.04.15 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP4725637A1 patent drawingFigure 1
  • EP4725637A1 patent drawingFigure 2
  • EP4725637A1 patent drawingFigure 3A~3B

AI summary

A laser processing system of the present disclosure includes a laser processing device that irradiates a workpiece with laser light, a light detector that detects return light including at least one of thermal radiation, visible light, or reflected light, the return light being generated by irradiating the workpiece with the laser light, and a controller that controls the laser processing device, in which the controller is configured to generate waveform data indicating an intensity of the return light during processing of the workpiece based on the return light detected by the light detector, extract a feature value from the waveform data, specify a first parameter having change among a plurality of parameters related to processing of the laser processing device based on the feature value, and change a second parameter among the plurality of parameters based on the first parameter.