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Keeping hot steel on track

SKS Vision Systems Oy
SKS Vision Systems specialises in optoelectronics and machine vision-based measurement and quality control systems, manufacturing top-of-the-range smart cameras and providing systems integrator services. Its technology has brought new standards to detecting web brakes in the paper industry and is also now helping steelmakers.

The field-proven capabilities of SKS Vision Systems’ technology, and its ability to operate under very challenging process conditions, will stand it in good stead when entering the 500-900 °C world of hot-dip zinc coating.

Ruukki has ordered a comprehensive package of smart cameras, servos, and control software for a coating line at its Hämeenlinna Works. Few systems anywhere are up to the challenge, and the fact that SKS Vision Systems has been able to draw on Control Techniques AC servo drives from SKS Control, also part of the SKS Group, for the delivery was a major plus.


Although machine vision and online control systems are nothing new to Ruukki, SKS Vision System’s delivery offers something different, as its cameras and servos, working together, will be used to keep the strip steel straight at all times, as it is tempered and enters the coating line, without the need for any additional system hardware. The only PC needed will be used to provide an interface for service purposes.

SKS Vision Systems’ cameras will monitor the steel as it progresses through the line and keep it on track at all times.

It is able to do this because SKS Vision Systems’ cameras, optical detectors, and smart vision sensors interpret the images they collect and convert them into control signals directly. This reduces the amount of data communications that has to take place and simplifies system design, making for greater reliability as well.

SKS Vision Systems’ cameras will monitor the steel as it progresses through the line and communicate any divergences from the standard path to the servos to eliminate them, as well as any long-term creep.

All data will be fed to the line’s automation system via a PROFIBUS field bus, giving operators the opportunity to set maximum and minimum parameters and offset values.

Eyes that never tire

SKS Vision Systems has been in the business of developing and producing machine vision systems for some 25 years, and many of its installations are required to operate in tough conditions. In the case of the Rautaruukki project, its cameras will be water-cooled to deal with temperatures as high as 900 °C.

The 100-200 °C temperatures that its paper industry systems operate in are not child’s play either, however. One of SKS Vision Systems’ VISIEYE™ units can replace numerous conventional systems with a single device on paper machines, coaters, calendars, and even outside the web area.

VISIEYE™ is the first integrated break detector to be based on high frame rate image-processing technology, and offers a level of performance never before achieved in papermaking. Following capture, images are analysed and processed in an integrated processing unit, which outputs detection and measurement signals directly.

> Kari Rahkola SKS
(Published in HighTech Finland 2010)