Steel industry

Thickness measurement

The main area of application for the non contact laser measuring technology in the steel sector is thickness measurement. Here, the areas of application are:

  • Hot rolled strip
  • Cold rolled strip
  • galvanised sheet metal
  • coated sheet metal

The thickness measurement as a one track system is possible with one as well as with two sensors. The one-sensor-measurement is carried out on a reference roll as basis. Here, it has to be taken into consideration that circularity errors of the roll as well as any lifting of the product from the roll are registered as changes in thickness and can lead to measurement-errors.

Therefore, as a standard the use of two sensors per measurement is recom­mended, whereby one sensor each is placed above and below the product. This layout allows for a vertical movement of the strip within the measurement range, without interfering with the measurement-value. Depending on the position and number of sensors there are various system configurations possible:

  • stationary thickness measurement of 1 x tracks
  • thickness measurements with adjustable measurement tracks
  • traversing measurements

In the case of the traversing measurement, different traversing frames in the shape of C- or O-frames of various widths are available. Traversing provides the possibility of continuous scanning of both length and cross profiles and, additionally, a measurement of thickness for static product edges.

Traversing errors, due to production tolerances and sagging of the traverse under its own weight, are compensated for by a respective traversing error correction carried out by the software.