News International Reduces Web Breaks

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.

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.

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, London (UK) site, News International has 16 Newsman 40 presses and, in the reel room, has 80 reel-stands, stocking some 5,000 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 at Wapping 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 give close control of the reel when it is almost fully unwound.

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

The solution comprised a 15kW Mentor II for each belt drive and a four kW Mentor II dc drive for each butt drive.

Existing motors were re-used and each drive was fitted with an MD29 Co-Processor module to provide the complex on-board calculations that were required.

The MD29 units, which have been programmed using SYPT to emulate and improve on the performance of the previous drives providing PlD control, calculate the speed and diameter of the reel and the required speed.

They replaced 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 20 seconds 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.

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

The move to Mentors has been a huge improvement, " said News International's technical support engineer Clive Stevens.

The main benefit that has been achieved 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 easier and faster to set-up, commented Stevens.

"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," he added.

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

Mentor II is claimed to be 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 system has 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.

News International sent 16 of their staff on training courses for Mentor II and Sypt software at Control Techniques in Newtown (Wales) and in-house at Wapping.

The reel stands carry paper weights of 42-55 gsm, in three different widths up to 1.5 metres, each reel being 15,000 metres long and weighing up to 981 kg.

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

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