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Failure to improve yield & quality in steel rolling mills can lead to significant production losses & dissatisfied customers.

While the steel mills are grappling with methods to improve yield which are cost effective, one yield improvement method that is effective, low cost & gives fast return of investment is crop cut optimisation.

The use of a vision based system to determine the exact amount of crop to be sheared off from a transfer bar is a widely accepted technology to determine the exact amount of crop to be sheared off. Coupled with an accurate strip speed feedback to the crop shear, the accuracy of crop shearing will be enhanced.

With higher cropping accuracy, higher yield improvement & reduced downstream trimming can be achieved at a very low cost.

Tata Steel Automation Division has developed a vision based system for crop cut determination coupled with an accurate strip speed feedback to the crop shear, to significantly reduce the crop cut length & loss of steel.



Principle of Operation

The crop optimisation system involves the following:

  • Imaging of the head & tail ends of the transfer bar after the last pass in the roughing mill.
  • Determination of the optimum shear lines
  • Downloading of the reference cut position to the shear control system
  • Accurate speed measurement & feedback to shear control system

The high speed image processing to achieve these functionalities is implemented using digital signal processors. Efficient contour tracing algorithms carry out profile analysis to determine the optimum cut position.



The major system components are:

  • Machine vision system for imaging of head & tail ends and strip speed measurement, up to 3rd order time derivative of distance
  • Efficient and robust algorithms to determine speed & image profiling even in presence of flowing scales and black patches
  • Pin-hole enclosure design to protect opto-electronics from extremely harsh plant conditions
  • High resolution CCD cameras with robust enclosure for maintenance free performance
  • Provision of manual settings for cut position



  • Reduction in yield loss due to crop cut upto 0.1%
  • Reduction in average crop cut length upto 60 %