Technical article: Optical measuring systems for plate mills

PLATE CHECK system measures all relevant dimensions of the rolling stock

The figure shows a computer-generated layout, which also shows the laser beams.

Complete geometry measurement of plates

Advances in camera technology have enabled a significant enhancement of dimensional measurements in plate mills. Slabs and as-rolled and cut-to-size plates can now be measured with a very high spatial resolution while providing more detailed and pinpoint evaluations of the measured data. This has become possible primarily due to the use of special high-resolution cameras and the integration of pre-processing capabilities, without which complex algorithms would not be feasible. On this basis, LAP has developed its new series of PLATE CHECK systems for laser-optical measurements in plate mills. PLATE CHECK measures all relevant dimensions of the rolling stock before it enters the rolling mill, after the rolling mill and all the way down to final inspection, significantly improving the efficiency of high-grade plate production.

In-line measurements of rolling stock macro-geometry allow quick and reliable assessments of the rolling process and immediate corrective intervention in the production process, if necessary. The systems are installed at different positions along the process chain measuring the specific process as required:

  • Plate width, which also forms the basis for calculating the complete plate shape, including the shape of the head and tail 
  • Plate thickness
  • Plate flatness
  • Plate speed and length

These measurements are the basis for reliable decision making during rolling and levelling, for deciding whether a product should be ‘released or blocked’, and for uninterrupted documentation of all process steps. High-precision optical measurement facilitates optimal material use, as it makes it possible, for example, to minimize the scrap from head and tail end cropping and side trimming and to optimize the cutting of plates from the mother plate. Uninterrupted dimensional measurement during all process stages guarantees that only product meeting customers’ specifications will be shipped.

Storage of the measured data allows analysis of the process at any time after the production process and hence identifies potential for further optimization. It also guarantees full traceability of each process step for every plate produced.

The article has been published in: MILLENNIUM STEEL 2017. Read the full article as PDF download

Images: LAP GmbH, iStockphoto LP, Fotolia