Laser Processing Head Centering via Thermal Conversion

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Solution Overview

Problem

Current laser processing machines face challenges in accurately and efficiently centering the laser beam within the nozzle bore due to manual intervention, visual assessment inaccuracies, and the limitations of external temperature sensors, which result in prolonged centering times and potential heat-related issues during the process.

Innovation Solution

The implementation of an internal conversion unit within the laser processing machine that converts the focused laser beam into secondary electromagnetic heat radiation, detectable by thermal radiation sensors, allowing for automatic and precise centering without the need for external temperature sensors or complex optical measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If manual centering with visual assessment is used, then the centering process can be performed with simple equipment, but the centering time is too long and requires practice and good visual acuity

Engineering Contradiction:
Improvecentering equipmentVSAvoidcentering time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent replaces manual visual assessment with an automated optical detection system. Sensors detect the position of the laser beam relative to the nozzle bore automatically, eliminating the need for manual visual centering. This substitution of mechanical/manual operations with automated sensing resolves the contradiction by providing both simplicity and speed.

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

Solution Approach 2:

The centering system performs self-centering through automated detection and adjustment. The sensors automatically detect beam position and the system autonomously adjusts the nozzle or beam alignment without requiring operator skill or repeated manual adjustments, achieving both simplicity and time efficiency.

Inventive Principle:
Principle #25Self-service

2Extent of automation

If external temperature sensors are used for centering, then automatic centering can be achieved, but the temperature sensors are too sluggish with a time constant of max. 20 ms and centering takes a long time

Engineering Contradiction:
Improveautomatic centeringVSAvoidsensor response speed
Core Design Contradiction:
Extent of automationVSSpeed

Solution Approach 1:

The patent replaces thermal sensing with optical sensing. Instead of using temperature sensors that measure heat diffusion (thermal process), the system uses optical sensors to detect the position of the laser beam directly (optical process). This substitution changes the measurement principle from thermal to optical, achieving both automation and fast response.

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

Solution Approach 2:

The patent changes the measurement parameter from temperature (thermal domain) to optical position (optical domain). By measuring the optical position of the laser beam rather than temperature, the system achieves much faster response times while maintaining automatic centering capability.

Inventive Principle:
Principle #35Parameter changes

3Extent of automation

If external temperature sensors are used for centering, then automatic centering can be achieved, but the temperature values are influenced by thermal radiation from the workpiece and exact centering is hardly possible

Engineering Contradiction:
Improveautomatic centeringVSAvoidcentering accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent replaces thermal measurement with optical measurement. By detecting the optical position of the laser beam rather than measuring temperature, the system eliminates interference from thermal radiation emitted by the workpiece. This substitution resolves the measurement accuracy issue while maintaining automation.

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

Solution Approach 2:

The patent introduces optical sensors as an intermediary measurement method that is not affected by thermal radiation from the workpiece. This intermediary sensing approach provides a clean measurement signal that is independent of workpiece thermal conditions, enabling precise automatic centering.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Extent of automation

If external temperature sensors are used during non-centered state, then centering can be monitored, but excessive heat loads on the nozzle occur for a longer period of time

Engineering Contradiction:
Improvecentering monitoringVSAvoidheat load on nozzle
Core Design Contradiction:
Extent of automationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces thermal-based monitoring with optical-based monitoring. By using optical sensors to detect beam position rather than temperature sensors, the system enables rapid detection and correction of misalignment, significantly reducing the duration of excessive heat loads on the nozzle while maintaining automated monitoring capability.

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

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 enables rapid, precise, and repeatable centering of the laser beam, reducing centering time and minimizing heat loads on the nozzle, thereby improving the quality and reliability of the laser processing operation.

Implementation Method 1

at least one inner conversion unit (9), in particular a conversion edge, which, if the nozzle opening (4) is not centered relative to the focused laser working beam (5) in the area of the nozzle opening (4), is suitable for converting the focused laser working beam (5) into a secondary electromagnetic heat beam (10)

Methodology Applied
Scientific EffectThermal conversion: Absorption (EM radiation)

Implementation Method 2

thermal radiation sensors (13), arranged inside the laser processing head (1), to detect the secondary electromagnetic heat beam (10)

Methodology Applied
Scientific EffectThermal radiation detection: Thermal Radiation

Data Source

PatentEP2667998B1Laser processing machine and method for centering a focused laser beam
Publication Date: 2020.11.18 BYSTRONIC LASER AG
  • EP2667998B1 patent drawingFigure 1
  • EP2667998B1 patent drawingFigure 2~3
  • EP2667998B1 patent drawingFigure 4

AI summary

The invention relates to a laser processing machine (LM), in particular a laser cutting machine, having long-wave laser radiation (in particular a CO2 laser), comprising at least one laser processing head (1), which has an interior (2) and a nozzle (3) having a nozzle opening (4) for allowing a focused primary beam (5), in particular a laser operating beam, to pass through onto a workpiece (6) to be processed and for directing a gas flow that encloses the beam, and an aligning device (15) having several sensors (13) for centering the primary (focused) beam (5), in particular the laser operating beam, and the nozzle opening (4) relative to each other. At least one first converting unit (9), in particular a converting edge for converting a (focused) primary beam (5) lightly touching or impinging into one or more secondary beams (10) of thermal radiation along at least one propagation direction (10A) in the direction of the sensors (13), is provided in the region of the nozzle opening (4). The sensors (13) are designed as thermal radiation sensors and are arranged in the interior (2) of the laser processing head (1) or of the nozzle (3).