Machining Fault Detection Using Intensity Drops in the Cutting Zone

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Solution Overview

Problem

Existing methods for detecting faults in machining processes, particularly cut breaks during cutting operations, are unreliable due to the inability to distinguish between real and pseudo-cut breaks, often misidentifying issues based solely on geometric features of the interaction area.

Innovation Solution

The method involves capturing and evaluating images of the interaction area in real-time using an imaging sensor, analyzing intensity profiles to detect local intensity drops, and combining this with geometric features to reliably identify cut breaks and other disturbances, such as support webs, through plausibility checks and threshold comparisons.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If detection is based solely on geometric features of the interaction area, then detection simplicity is maintained, but reliability of fault detection deteriorates due to inability to distinguish real and pseudo-cut breaks

Engineering Contradiction:
Improvereliability of fault detectionVSAvoidcomplexity of detection method
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple detection features (geometric features of the interaction area, intensity profile features, and local intensity drop detection) into a unified detection system. This merging of multiple detection approaches allows reliable distinction between real cut breaks and pseudo-cut breaks while maintaining a coherent detection framework, resolving the contradiction between reliability improvement and complexity increase.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediary evaluation step that analyzes intensity profiles and detects local intensity drops within the interaction area. This intermediary analysis acts as a mediator between raw geometric data and final fault detection, providing additional verification to distinguish true faults from false positives without requiring completely new detection hardware.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple parameters and plausibility checks are used to improve detection accuracy, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improveprecision of disturbance detectionVSAvoidcomplexity of evaluation system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the detection process into distinct analytical components: geometric feature extraction, intensity profile analysis, local intensity drop detection, and plausibility checking. Each segment handles a specific aspect of the detection task, allowing high measurement precision through comprehensive analysis while managing complexity through modular organization of the evaluation system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes changes in optical intensity parameters within the interaction area as additional detection criteria. By monitoring intensity profile variations and local intensity drops, the system gains additional measurement dimensions that improve detection precision without requiring fundamentally new detection hardware, thus managing complexity while enhancing precision.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If real-time image evaluation is performed to detect faults immediately, then productivity is maintained, but measurement precision requirements increase

Engineering Contradiction:
Improvemachining productivityVSAvoidprecision of real-time detection
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary analysis of intensity profiles and geometric features as images are captured in real-time, before final fault determination is made. This preliminary action allows the system to maintain high productivity by continuously processing data, while the accumulated precision from multiple analyzed parameters ensures accurate detection when thresholds are evaluated.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where detected features (geometric properties, intensity variations) are continuously evaluated against established criteria. This feedback loop allows real-time detection with maintained productivity, as the system can quickly determine whether measured parameters indicate actual faults or normal variations, ensuring both speed and precision.

Inventive Principle:
Principle #23Feedback

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 allows for accurate detection of cut breaks and other disturbances, enabling timely intervention to prevent incomplete cuts and adapting the machining process to account for position-dependent disturbances, thereby improving process reliability and quality.

Implementation Method 1

an image capture device for recording an image of an area to be monitored on the workpiece, which area comprises an interaction area of the processing tool, in particular the laser processing head, with the workpiece

Methodology Applied
Scientific EffectLight intensity detection: Photoelectric Effect

Data Source

PatentEP4304801B1Method for identifying a fault in a machining process, and processing machine
Publication Date: 2025.06.25 TRUMPF WERKZEUGMASCHINEN GMBH & CO KG
  • EP4304801B1 patent drawingFigure 1
  • EP4304801B1 patent drawingFigure 2~3a
  • EP4304801B1 patent drawingFigure 3b~3c

AI summary

The invention relates to a method for identifying faults in a machining process, in particular in a cutting process, comprising: machining a workpiece, in particular by cutting, by moving a machining tool, in particular a laser machining head, and the workpiece relative to one another, recording an image of an area to be monitored on the workpiece, comprising an area of interaction (18) between the machining tool and the workpiece, and evaluating the image of the area to be monitored in order to identify at least one fault in the machining process. To identify the fault, the evaluation of the image involves detecting the presence or absence of a local intensity drop (ΔI) in an intensity profile (I) within the area of interaction (18) along a direction of advance (V) of the machining process. The invention also relates to an associated processing machine.