Optima Control Solutions

When presented with poor print and fold quality, coupled with sleep depriving reliability for three ageing gravure printing presses, Optima Control Solutions Ltd. provided a remarkably successful answer. Money is in short supply in today’s manufacturing arena, an option to improve the presses manufacturing efficiency at a fraction of the price of a new machine was immediately attractive to the management team at Polestar Purnell, Somerset.

Analysis of performance data for the three presses at their Paulton site indicated that the reliability of the machinery was significantly influencing both the factory and group performance. Their poor reliability and faltering quality of print impacted on machine run speeds and product quality. Polestar asked Optima to survey the printing machines and suggest a possible remedy. It was clear to Optima that the control equipment, the machine’s original DC drives manufactured by Cerutti, were past their operational best.

Technology and techniques for controlling web have advanced dramatically over the lifetime of these machines and support for the existing equipment was all but gone. Optima suggested the benefits of new technology, high performance control equipment that is supportable and available, correctly applied would bring positive results. These results being higher press speeds, faster make-ready times and remarkable improvements to fold and print register accuracy.

So Optima’s brief was to replace the ageing control systems on 3 Cerutti 1759 model gravure presses. Their goal was to improve manufacturing efficiency for the Paulton factory. After their initial survey a detailed proposal was submitted. The document described the existing control principles for the presses, how these could be improved, and where advanced control methods could be applied to presses of this type. Optima included the customer’s site standard equipment where appropriate and recommended new components to replace obsolete original equipment. Once accepted and commercial terms agreed, the project engineering activity followed. Optima’s defined and quality audited design procedures were applied to the whole engineering process.

The Project

The Engineering Activities

Optima’s project engineers attended site and detailed all aspects of the presses’ operation, from the main operator controls through to the smallest of on-machine components. All the technical data and operational methods and techniques for the printing presses were gathered. This data was then used to produce a detailed specification document in which each push button, lamp, motor etc. was identified and given a comprehensive physical and functional description. Most of the original operational methods for the machine were retained, however Optima suggested some simple changes that were to make a noticeable improvement to the press start-up and make ready times.

This specification was reviewed with the customer and, once agreed with them it was signed off as the engineering design template. Having produced the functional design specification and nominated the equipment to be integrated, Optima’s engineers then designed the control system, producing schematic circuit diagrams and equipment layout diagrams. These were again reviewed and approved by the customers site engineers and importantly the production staff. Optima’s proposal included a distributed control system. The drives used a high speed fibre-optic network, linked to the PLC system by a Profibus network. The main operator interface was a graphical, touch screen HMI. The system’s software was critical to the reliability of the machine and to the operators and maintenance engineers too. Great consideration was made by Optima to ensure the system was intuitive to use and simple to diagnose under fault conditions. To achieve this Optima used state transition programming techniques. Optima’s control cubicles were manufactured to a high standard, their construction addressed technical issues, the ease that the panels could be worked upon and aesthetic features too. Optima then fully tested the control panels, with all hardware and software installed, at their test facilities. Polestar’s engineers witnessed these test activities prior to shipping the equipment to their site. With Optima’s assistance on technical matters, Polestar’s engineering staff assumed responsibility for the installation activity on this project. Optima’s scope of supply included schematic circuits, cable schedules and application advice for any high level technical issues. Any critical activities, say encoders or field bus terminations were carried out by Optima’s own project engineers.

Commissioning

Once installed, Optima’s engineers attended site to put the machine into service, setting up the drives, load cells, tension and phase loops. As this activity progressed, the Polestar staff’s involvement increased, engineers, operators and supervisors training advanced with each commissioning activity.

Documentation

As part of this work, as with every contract, Optima provided a fully documented user manual, with final drawings, specification, software backups and any proprietary component information. Certificates of conformance (where necessary) were also published and attached.

The Results

The positive outcomes of this project activity are many. The plant’s manufacturing efficiency has improved by 50% on its original value. Register and fold accuracy are predicable and better than those enjoyed when the press was first installed. Product quality is much improved whilst line speeds have increased significantly. Polestar’s group operations manager, Mr. David Forrester commented, "The success of the control system upgrades has allowed us to have far greater work planning flexibility, jobs are no longer allocated based on the individual machines’ performance criteria. Consistency in machine performance means that we can fully utilise normal shift patterns with minimal overtime commitment".

After Sales

Optima now continue to provide expert advice and spares and engineering support on these and other machines in the Polestar Group. If the scenario of poor product and unreliable machinery sounds familiar, then you too might enjoy all the benefits of a control system upgrade. Contact Optima Control Solutions Ltd. at their offices in Blackburn, Lancashire on 01254 27 28 29, ask to speak to Michael Hill or Peter Sharpe, they will be pleased to discuss your application with you.