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Accurate to the micrometre - readychain in laser measuring devices for rolling mills


  • What was needed: Reliable ready-to-install harnessed energy supply system for precise laser measuring device
  • Requirements: Reliability and smooth running of the energy supply system to achieve precise results in laser measurement
  • Product: readychain® harnessed energy chain
  • Field of application: Rolling mills
  • Success for the customer: The ready-to-install harnessed readychain systems save the customer assembly time.

About the laser measuring device VTLG:In 2014, the new measuring instrument with the designation VTLG was presented for the first time by Friedrich Vollmer Feinmessgerätebau GmbH in Hagen. Two laser distance sensors are arranged opposite each other. The laser beams are in a common axis. A cumulative distance measurement enables the recording of the thickness of a material positioned in the beam path. The measuring rate is up to 80 kHz. This works with a resolution of 0.05 µm, whereby a measuring accuracy of +0.5 µm is achieved. This opens up completely new possibilities for the rolling mill operator to produce strip and foil with reproducible thickness.

Laser measuring device VTLG

The challenge

Cold rolling mills operate at speeds of up to 2,000 metres per minute. A uniform strip thickness is a very decisive quality criterion, wherein the micrometre really matters. The more valuable the material is, the more precisely it must be rolled. This is because precious metals are cold-rolled and an oversize in this case is not only a quality defect, but also really expensive from the manufacturer's point of view.
Friedrich Vollmer Feinmessgerätebau GmbH in Hagen measures in the micrometre and millisecond range. The Vollmer design engineers have chosen laser measurement as the measuring method. And since conventional lasers do not yield exact results under the ambient conditions of the rolling process with high temperatures, steam, humidity and oil mist, a proprietary laser technology was developed.
For most users, a measurement of the strip thickness at the centre line position is sufficient to control the thickness. The sensor system then moves to the centre line position and is thereby adjusted. Other users continuously move the measuring device across the width of the strip to measure the thickness at different positions. For this reason the energy and signal supply must be movable in the C-frame.

VTLG in operation

readychain Vollmer VTLG


For the task of mobility of the energy and signal supply system in the C-frame, the designers of the VTLG used a [link pagenr="22999" title=" energy chain"] from igus right from the start - and saw a need for optimisation. It was quite complicated, to cut all cables to length, to harness and then to fill the chain
Therefore igus proposed three optimisation measures that were put into practice: First, the cables were divided from one into two chains. This reduces the forces acting on chains and cables and also saves space, which is extremely scarce in the C-frame.
Second, Vollmer now uses chainflex cables from the igus range, which were specifically developed for moving applications. This prevents cable defects.
Third, the company procures the chains filled and harnessed, which means ready for installation as readychain, thus saving installation time.

To the readychain® overview

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