Online Roughness Measurement
AMEPA online measurements of the surface area profile provide fundamental advantages for the customer:
The laser line and the galvanised surface area texture (EDT in this case) are clearly visible. The example in the screenshot shows the on-line Ra and RPc results over the coil length with the most recent microscopic image. The high dynamics provided by the system enable the operator to rapidly correct the overshoot of the roughness during the coil exchange (in the middle of the diagram).
System tests comparing SRM results with conventional stylus measurements have clearly indicated the high reliability and accuracy of the system. In the example provided, the good correlation between the off-line stylus results and the on-line SRM results is easily visible.
A validation measurement is an inspection of the sensor with regard to its optical characteristics and its proper operational functionality.
Automated validation measurements enable the sensor to be inspected during operation. This always ensures the process and documents a consistent quality of the measurement results.
The SRM Surface Roughness Measurement System functions on the basis of line projection – a two-dimensional laser triangulation method which is patented by the Centre for Research in Metallurgy (CRM, Liège).
The laser line is projected onto the strip up to 100 times per second. The integrated CMOS camera subsequently makes a microscopic image of the laser line and the surface area structure. The clearly visible laser line is inspected for plausibility by utilizing intelligent image processing, filtered, and processed to calculate the roughness values. The measurements are combined in such a way that the conditions according to the DIN EN ISO 10049 standard are approximated. A reaction time of approx. 0.5 seconds to roughness alterations can be achieved when operating at 60 Hz and averaging over 30 measured values.
The distance sensor is positioned in the middle of the distance variations. It thereby triggers the measurement and image acquisition. This ensures that the focus for the optics is always at the correct distance. The sensor automatically compensates for varying strip thicknesses with its integrated drive units.