Cutting Nozzle Wear Detection via 3D Structured Light

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Solution Overview

Problem

Current methods for determining the state of wear in cutting nozzles of laser processing machines are unreliable and time-consuming, failing to accurately assess wear-related changes in the nozzle shape that affect gas flow and cutting quality, leading to inconsistent cutting results and measurement errors.

Innovation Solution

A method using structured light illumination and three-dimensional evaluation to assess the cutting nozzle's shape, including depth information, allowing for a precise determination of wear-related changes such as indentations, ejections, and adhesions, by comparing the actual shape to a target shape stored in a memory unit, using techniques like triangulation, dark field, and bright field illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual checking of the cutting nozzle is performed, then the state of wear can be assessed, but it requires time-consuming and costly downtimes and operator experience

Engineering Contradiction:
Improvereliability of wear assessmentVSAvoiddowntime for manual checking
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The cutting nozzle performs self-diagnosis by serving as its own measurement object. The sensor unit records the shape of the cutting nozzle directly, enabling automatic wear detection without requiring manual intervention or operator expertise. This self-service approach eliminates downtime while maintaining reliable wear assessment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical inspection process is replaced by an optical measurement system. A sensor unit with illumination device and camera device captures optical images of the cutting nozzle, and an evaluation unit automatically processes these images to determine wear state, substituting human operators with automated optical-mechanical systems.

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

2Measurement precision

If conventional image evaluation is used, then the cutting nozzle appearance can be recorded, but wear-related changes affecting gas flow cannot be detected

Engineering Contradiction:
Improveprecision of wear detectionVSAvoiddepth information about cutting nozzle shape
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The measurement system transitions from two-dimensional image recording to three-dimensional shape measurement. By capturing depth information and spatial coordinates of the cutting nozzle surface, the system can detect wear-related changes in gas flow channels and surface topography that conventional 2D imaging cannot reveal.

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

Solution Approach 2:

Structured light patterns serve as an intermediary to encode three-dimensional surface information. The illumination device projects structured light patterns onto the cutting nozzle, and the sensor unit captures the deformed light patterns, which act as intermediaries to reveal the actual 3D shape and wear characteristics of the nozzle surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides a more objective and precise assessment of the cutting nozzle's wear, enabling timely decisions on nozzle replacement and improving the reliability and quality of the laser cutting process by accurately quantifying wear's impact on gas flow and cutting ability.

Implementation Method 1

Illuminating the cutting nozzle by means of an illumination device, wherein the cutting nozzle is illuminated in the light section method

Methodology Applied
Scientific EffectStructured light illumination: Light

Implementation Method 2

by means of one or more incident light sections at a triangulation angle, which are projected onto the cutting nozzle as a line of illumination

Methodology Applied
Scientific EffectTriangulation:

Implementation Method 3

recording the illuminated cutting nozzle by means of a camera device

Methodology Applied
Scientific EffectPhotography: Photography

Implementation Method 4

determining the state of wear of the cutting nozzle by evaluating the recorded camera recording

Methodology Applied
Scientific EffectImage processing: Image Processing

Data Source

PatentEP2837461B1Method for determining the wear on a cutting nozzle and laser processing machine for carrying out the method
Publication Date: 2017.05.24 TRUMPF WERKZEUGMASCHINEN GMBH & CO KG
  • EP2837461B1 patent drawingFigure 1a~2
  • EP2837461B1 patent drawingFigure 3~4

AI summary

In a method for determining the wear state of a cutting nozzle (1) of a laser processing machine, the wear state of the cutting nozzle (1) is determined according to the invention based on the three-dimensional shape (2) of the cutting nozzle.