Laser-Nozzle Alignment by Reflection Sensing in Fluid Jet Machining

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Solution Overview

Problem

Conventional apparatuses for machining workpieces with laser beams coupled into fluid jets face challenges in automatically and precisely aligning the laser beam with the nozzle aperture, leading to time-consuming and error-prone processes due to difficulties in determining the nozzle bore position, especially with dot contaminations present.

Innovation Solution

An apparatus and method utilizing an optical sensing unit to detect and computationally evaluate laser beam reflections from the nozzle, allowing for real-time control of the laser beam's position to achieve precise automatic alignment by identifying characteristic sensing patterns indicative of alignment with the nozzle aperture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the laser beam is defocused and directed onto the fluid jet generation nozzle for visual identification, then the entire nozzle is illuminated making it visible to the user, but the position of the nozzle bore becomes difficult to determine and alignment becomes error-prone due to dot contaminations

Engineering Contradiction:
Improvenozzle illuminationVSAvoidbore position determination
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by making the laser beam focused (concentrating energy at a specific point) rather than defocused, and by using a sensing unit that detects reflections only from specific locations. This allows the bore position to be identified precisely through the characteristic reflection pattern from the bore aperture, while contaminations produce different patterns that can be distinguished computationally.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent replaces the manual visual identification method with an automated optical sensing and computational evaluation system. The sensing unit detects laser reflections and the control unit computationally evaluates the sensing signals to automatically determine bore position and alignment, eliminating the need for manual visual inspection and reducing errors from contaminations.

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

2Device complexity

If manual visual alignment procedure is used, then the apparatus structure remains simple, but the alignment process becomes time consuming and error prone

Engineering Contradiction:
Improveapparatus structureVSAvoidalignment time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent implements self-service by enabling the system to automatically perform alignment without manual intervention. The sensing unit continuously monitors laser reflections from the nozzle, and the control unit automatically adjusts the laser beam position based on the detected reflection patterns, making the system self-aligning and eliminating time-consuming manual operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies feedback by using the sensing unit to continuously detect laser reflections from the nozzle surface and bore, and feeding this information back to the control unit which adjusts the laser beam position accordingly. This closed-loop feedback system enables automatic real-time alignment optimization, significantly reducing alignment time while maintaining simple apparatus structure.

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

Enables fast and precise automatic laser-nozzle alignment with high success rates, reducing alignment time and minimizing errors, while maintaining a simple and compact apparatus implementation.

Implementation Method 1

a sensing unit configured to sense laser light reflected from a surface of the nozzle unit and produce a sensing signal based on the sensed reflected laser light

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

the laser beam is guided in the fluid jet onto the workpiece by means of total internal reflection

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3533557B1Apparatus for machining a workpiece with a laser beam coupled into a fluid jet, with automatic laser-nozzle alignment ; method of aligning such a beam
Publication Date: 2021.05.26 SYNOVA SA
  • EP3533557B1 patent drawingFigure 1
  • EP3533557B1 patent drawingFigure 2
  • EP3533557B1 patent drawingFigure 3

AI summary

The invention relates to an apparatus (100) for machining a workpiece with a laser beam (101) coupled into a fluid jet. The apparatus (100) comprises a laser unit (101a) for providing the laser beam (101), a nozzle unit (102) with an aperture (102a) for producing the fluid jet, and an optical unit (103) configured to provide the laser beam (101) from the laser unit (101a) onto the nozzle unit (102). Further, the apparatus (100) comprises a control unit (104) configured to control (108, 110) the optical unit (103) and/or nozzle unit (102) to change a point of incidence (109) of the laser beam (101) on the nozzle unit (102). The apparatus (100) also comprises a sensing unit (105) configured to sense laser light (106) reflected from a surface (102b) of the nozzle unit (102) and produce a sensing signal (107) based on the sensed reflected laser light (106). The control unit (104) is particularly configured to evaluate the sensing signal (107) and to determine a defined sensing pattern in the sensing signal (107) indicative of the laser beam (101) being fully and/or partially aligned with the aperture (102a).