3D rendering of plate flatness; the red line represents the virtual 1-m ruler (left and middle)
Illustration of plate thickness in the millimeter range (right)
The decision in favour of the nokra system was a step into unknown territory for voestalpine because planar thickness measurements of heavy plates had never been realized before.
However, it rapidly became clear that the system is excellently suited to document the plate quality, help enhance process understanding and optimise the processes.
The high resolution of the data acquired opens up entirely new possibilities for analyses. While it used to take the inspection staff one or even two shifts to measure a plate manually, the new system now provides more than a million measuring points in just ten minutes. Additionally, more comprehensive and reliable information can be gained from the precise, high-resolution and objective measurement data provided by the new system. Thanks to the time-saving measurements, a much higher throughput can now be achieved with the same
number of operators.
Based on the new data available, it is now possible to analyse any irregularities detected on the plates more deeply, enabling the causes of certain defects to become evident for the first time and helping to get a better understanding of the overall roll-bonding process. The flatness data from the full-surface measurements, for example, can be used to optimize the rolling and leveling processes. Plasma cutting can now be controlled based on entirely objective criteria – i.e. without influences by humans - using the data from the contour measurements.
Further potential with a view to gaining a deeper overall process understanding and achieving even more process security could be derived from using the system to measure the plates after each one of the about ten process stages of roll-bonding.
The new system provides a great advancement not only in terms of its high measuring precision, but also regarding the process digitalisation it enables. All the measured data are automatically stored and available for a virtually unlimited period of time. When rolling plates for special requirements, for example, it is now possible to access process parameters previously used to produce similar kinds of plates.
A positive side effect of the optical system is that it renders a photographic, high-resolution image of both plate surfaces. In this way, voestalpine can document that all the plates leaving the mill are free of surface defects. Additionally, the stampings can be checked to ensure that all data have been correctly assigned.
The new system fulfills all performance requirements specified by voestalpine. From the outset, it was planned that the system should take over additional tasks in the future. This will primarily entail expanding its software capabilities to be able to perform data analyses that take into account a wider range of criteria. This would be applicable, for example, to pipelines intended for hydrogen transport. These products pose a new challenge as the cladding for this specific use has to comply with a number of new requirements.