Quicker positioning helps steel mill meet customers’ demands

To extend the range of its steel piling sections to include several new designs with tighter tolerances, British Steel sought new control systems and drives for its roller straightening machines (RSMs) in its heavy section mill in Scunthorpe, North Lincolnshire, U.K. Upgraded piling sections help increase construction efficiency because they can be driven faster when making steel walls.

机已经升级其产品质量和发送t range for two years, which increased demand and volume. This required faster and more accurate setups of the RSMs for new structural sections, more precise feedback for accurate positioning, as well as improved data acquisition and storage, communications, and an operator interface to visually display parameters, mimics, trends, and other data.

传统轧机生产渠道、横梁、columns, and sheet piling sections up to 630-mm wide in a range of lengths, weights, steel specifications, and finishes. Each machine has seven straightening rolls, adjustable for each new section. The seven roll spindles have horizontal, vertical, and axial plane movement and are motor-controlled to make sure the rolls are aligned properly and correct straightening forces are applied.

Section straightness is ensured by two RSMs, one for lighter beams and pilings with up to 1,400 roll centers and another for larger sizes with up to 1,800 roll centers. Control Techniques (Leeds, U.K.) won the contract to improve the larger RSM.

“Successful machine setup previously relied on the operator, but our new position control helps achieve product straightness more quickly and maintain it,” says Graeme Hornsby, British Steel’s operations director. “Upgrading the RSM allows us to store configurations for each size and type of product. It also gives us rapid repeatable setups, improved reliability, and easier future upgrades.”

New controls, new performance

Control Techniques’ system includes 18 vector drives—from 2.2 to 25 kW—for the RSM’s critical positioning drives; Directax positioning modules that calculate the roll spindles’ positioning; Mentor drives for dc motor control; and a GEM400 programmable logic controller (PLC) that communicates with the mill’s VAX supervisory computer, operator controls, and positioning system.

The drives are controlled by the Directax intelligent motion controllers, which calculate velocity profiles under which the vector drives operate. Each positioning drive motor is fitted with a 1,024 ppr encoder that provides position feedback to the vector drive to within 1,000th of a revolution. Required movements are entered into the PLC and downloaded into the Directax controllers, which enables the drive, then supplies speed profiles to move the vector-controlled motor accurately.

“Recipes” of the best configurations for optimum straightness for each product are stored and retrieved as needed. Control Techniques’ system also include full-status monitoring and a full-logging alarm system with 1,000 conditions.

“The new system will pay for itself quickly because setups between products that used to take 10 or 20 minutes can now be achieved in seconds,” says Mr. Hornsby. “We no longer need the position transducers and limit switches, which were often knocked off the machine or damaged. The operator can now see where the rolls are without having to measure positions, which is much easier and more accurate. We now have over 200 setup variations stored, and our product quality has never been so good.”

For more information, visitwww.globalelove.com/info .

Do you have experience and expertise with the topics mentioned in this content? You should consider contributing to our CFE Media editorial team and getting the recognition you and your company deserve. Clickhereto start this process.