Reel stand drives keep the presses running

The replacement of unreliable analogue drives on newspaper reel stands at News International has reduced web breaks and improved feed accuracy for several of the company's huge presses.

The replacement of unreliable analogue drives on newspaper reel stands at News International, with Mentor II DC drives from Control Techniques, has reduced web breaks and improved feed accuracy for several of the company's huge presses.

To date, 15 reel stands have been upgraded and a further 10 are on order.

Each press at the newspaper giant, which produces The Times, Sunday Times, The Sun, The News of the World and other big circulation publications, is capable of producing 80,000 newspapers per hour.

At its Wapping site, News International has 16 Newsman 40 presses and, in the reel room, has 80 reel-stands, stocking some 5000 reels of newsprint in varying sizes and weights.

The continuous feed of newsprint to the presses is a crucial part of the production, requiring a high level of automation and accuracy to keep the presses running.

In particular, this entails very precise speed synchronisation between the reel and the web, particularly crucial during reel changeover, when the paper is spliced on the fly.

One result of poor splicing is ridged paper that can snag and often tear, causing a web break.

With the five reel stands in question, the original analogue drives were becoming more unreliable and maintenance was climbing steeply, so attention centred on the two crucial drives on each web stand; the main belt drive and the butt drive that gives close control of the reel when it is almost fully unwound.

Mentor II digital DC drives from Control Techniques were chosen because of their onboard processing capability to provide a stable digital platform to address the problems that News International was experiencing with synchronisation drift from its analogue drives.

The project team of Clive Stevens, Paul Wrigglesworth and Clive Baldwin worked closely with Control Techniques to produce a robust technical solution.

This comprised a 15kW Mentor II for each belt drive and a 4kW Mentor II DC drive for each butt drive.

Existing motors were re-used and each drive was fitted with an MD29 coprocessor module to provide the complex onboard calculations that were required for this type of application.

The MD29 units, which have been programmed using Sypt to emulate (and improve on) the performance of the previous drives providing PID control, calculating the speed and diameter of the reel and the required speed, replacing the previous dancer feedback control that became increasingly insensitive as the reel unwound.

The MD29 units also provide signal routing for other processes and improve the performance during crash stop, allowing 300% current for 20s to maintain the web.

During a crash stop, the reel-stand is ahead of the press when stopping and has a greater buffer of paper around the dancer rollers, reducing the possibility of the web going slack.

Additional reference feedback was installed as well as a new small board developed by News International to act as an interface between the Mentors and the existing EAE control signals.

"The old analogue drives were becoming a real headache", says Technical Support Engineer Clive Stevens.

"It was increasingly difficult to source spares and, after a problem, it could take a couple of hours to go through the setup procedure to get them back on line.

The move to Mentors has been a huge improvement".

"There are five main benefits from the installation", he continues.

"The main one is the much-improved synchronised speed-holding at paste with butt drive control improved generally.

The crash-stop control of the web is much better too and the Mentors are very much easier, and faster, to set up.

Above all, there is no analogue signal drift.

It's been a great success and one that we are repeating reel stand by reel stand".

The Mentor II digital DC drive range spans 24 to 1850A, from stand-alone installations to networks using most industry-standard communication protocols.

Easy to set up and commission using Mentorsoft software and with off-the-shelf software for many common requirements such as digital speed and position loop, centre-winder, shaft orientation, s-ramp and others, the Mentor II can be found in applications as diverse as steel and paper mills, textile and plastic manufacturers and cranes, conveyors and wire drawing.

With standard features that include single- and four-quadrant operation, field and phase loss protection, 0.1% speed holding for 100% load change, with tacho feedback, advanced auto-diagnostics and software expandable using MD29 application modules, Mentor II has been a market leader for some years.

News International sent 16 of its staff on training courses for Mentor II and Sypt software.

These were at Control Techniques in Newtown and in-house at Wapping.

The training was tailored around News International's specific use of the Mentor drive and its associated software.

The reel stands carry paper weights of 42-55g/m2, in three different widths up to 1.5m, each reel being 15km long and weighing up to 981kg.

When the press is up to speed, one reel lasts just 20min.

Around 38 deliveries of newsprint are made daily to Wapping and, in an average week, some 5000t of newsprint is used.

The newsprint is delivered to the press reel stands by robotic reel handling equipment as required.

News International prints its newspapers at three main printing sites: Wapping in London, Liverpool and Glasgow.

In an average week, approximately 20 million copies of The Sun, 5 million copies of The Times, 4 million copies of The News of the World, 1.5 million copies of The Sunday Times and 2 million copies of contract newspapers are printed by the three sites.

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