![Page 1: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/1.jpg)
Online Roughness Measurement Online Topography Measurement based on the Light Sectioning Principle Dr.-Ing. Wolfgang Bilstein, Amepa GmbH
![Page 2: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/2.jpg)
Content
Motivation
Optical online roughness measurement
Implementation
Waviness measurement – Online
Combined roughness and oilfilm measurement
Resumé
![Page 3: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/3.jpg)
Motivation
Significance of roughness and waviness for sheet surfaces
Traditional roughness measurement
Welf Schiefer: „Mitfahrgelegenheit“
![Page 4: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/4.jpg)
Significance of roughness for sheet material
High surface quality strips required due to:
Complex metal forming
Increase of productivity
Paints will be applied without filler in the future
Higher demands on surface finish (homogenious appearance for material mix of modern cars)
Rising importance of topography measurement
![Page 5: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/5.jpg)
Traditional measurement of roughness
Mechanical stylus measurement: - Impossible on moving product - spot test at the end of a coil or - on sample in laboratory
dxxzl
Ra
l
0
)(1
![Page 6: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/6.jpg)
Optical roughness measurement – online
Different approaches to measure the roughness online
Light sectioning principle
Laboratory 3D scan examples with light sectioning (Waver and EBT)
![Page 7: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/7.jpg)
Different approaches to measure the roughness online
Relativ measuring principles:
Scattering of light as measure of an optical roughness which can be correlated with the mechanical roughness
Speckle analysis
Absolut measuring principles
Triangulation
Deflectometry
Light sectioning principle (2D Triangulation)
![Page 8: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/8.jpg)
Necessary properties of an online system
Absolute measurement as close as possible to stylus system by optical means
Usable for all sheet surfaces and coatings
Unaffected by production environment, e.g. speed, vibrations etc.
Verifiable by user - not a black box
High dynamics for process control
High accuracy and good comparability to stylus results
![Page 9: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/9.jpg)
Light Sectioning Principle
1. Laser line projected onto
surface (here 45°)
2. Imaging of distorted line with camera
3. Evaluation of line distortion gives a high resolution surface profile
4. Calculation of roughness parameters
![Page 10: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/10.jpg)
Laboratory 3D scan with the light sectioning principle
3D depth maps (grayscale coded, ca. 1x1mm2): a) Waver b) EBT textured hot dip galvanized steel sheet
![Page 11: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/11.jpg)
Implementation
Integration of the system into a rolling mill
Example for an installation
Online surface images
Correlation with stylus measurement
![Page 12: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/12.jpg)
Excentricity of roll
Trigger level Specifications: Magnification 6x FOV1200x400µm WD 28mm 20 (90) images/s Wavelength 905nm Pulse length 8ns
Integration of the system into a rolling mill
![Page 13: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/13.jpg)
Example for an installation
Installation in Feuerverzinkung (vmax = 180m/min) mit definierten Schutzbereichen
![Page 14: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/14.jpg)
Online surface images
a) Ra = 3.5µm
Sheet surfaces: a) Annealed steel b) Hot dip galvanized (EBT texture) c) Electrogalvanized (EDT texture)
b) Ra = 1.6µm
c) Ra = 1.2µm
![Page 15: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/15.jpg)
Correlation with stylus measurement
a) Stylus operator vs. Stylus laboratory b) Stylus vs. optical online
![Page 16: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/16.jpg)
Waviness measurement – online
Waviness measurement – Wavisurf
Laboratory results
Online results
Prozess optimization
![Page 17: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/17.jpg)
System requirements: • High speed camera (ca. 4kHz) • Dynamische synchronization with strip speed • Precise allignment of the optics
Waviness Measurement – Wavisurf
![Page 18: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/18.jpg)
Laboratory results
Comparison of mechanical stylus with optical waviness measurement (sample speed 60m/min)
![Page 19: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/19.jpg)
Online results
Comparison of mechanical stylus with optical waviness measurement (vmax = 240m/min)
![Page 20: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/20.jpg)
Prozess optimization
Evaluation and quantification of process parameters onto the waviness (hot dip galvanizing line)
![Page 21: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/21.jpg)
Combination of roughness and oilfilm measurement
Offline analysis of blanks
Oil film distribution
Roughness distribution
![Page 22: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/22.jpg)
Prediction of deepdrawing behaviour
Used by:
Audi
Daimler
![Page 23: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/23.jpg)
Resumé
SRM is the standard system for online-roughness measurement in Europe
Benefit: Modelling of processes
Process control
Process optimization
Product improvement
Auditing
Waviness measurement WMS: Extension of the roughness measuring system for the evaluation of waviness parameters (Wsa, Wa0.8 etc)
![Page 24: Online Topography Measurement based on the Light ... · Higher demands on surface finish ... Rising importance of topography measurement . Traditional measurement of roughness Mechanical](https://reader036.vdocuments.us/reader036/viewer/2022081405/5f0b8f2e7e708231d4311cc0/html5/thumbnails/24.jpg)
Thank you very much for your attention.