Automation in web offset printing

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The high-speed, high-volume Newslight 36 is the largest printing press in Prakash’s portfolio, featuring up to seven decentralised stations, at times spanning 25 to 50 meters. For the robust network, high-performance I/O and motion control systems required for such an expansive system, Prakash relies on B&R’s control technology and POWERLINK communication.

Every morning, we open our front door to find a neatly rolled bundle that tells us all about what’s happening around the world – a newspaper! Our cup of tea and breakfast wouldn’t be complete without it. However, the act of printing a newspaper, magazine or book is just as challenging as the process of creating its contents in the first place. The next time you hold a newspaper in your hand, you may find yourself pausing for a moment to appreciate all the technology behind it.

Faridabad-based Prakash Web Offset Pvt Ltd is one of the leading manufacturers of web offset presses in India, bringing cutting-edge technology to the nation’s print and publication industry. Prakash’s modern plant is fully equipped to build all of its presses in-house in order to maintain the required quality. The high-speed, high-volume Newslight 36 is the largest press in Prakash’s portfolio, requiring communication between each of its print units and folder and control panel – a span as much as 25 to 50 meters.

High volume, high efficiency

When it comes to printing high volume publications on a fast moving continuous substrate, a web offset press like the Newslight 36 from Prakash is the appropriate tool for the job. The printing process begins with large diameter reels of paper being loaded onto the infeeds with automated reel changers for the webbing up of the press. As the first reel nears its end, the auto-splicing unit begins to rotate the new reel up to its operational speed of 7 meters per second and then automatically splices the two rolls together. This eliminates the time consuming process of changing reels and feeding a new web through the system as well as both printed and unprinted waste.

The blanket-to-blanket web offset press prints on both sides of the web simultaneously while optical sensors and tensioning rollers keep the paper web precisely aligned and maintain the desired tension to avoid tearing and creasing. In blanket-to-blanket printing, the consistent pressures of the two blanket cylinders pressing against each other in perfect register while transferring the ink from the image areas on the plates on both sides of the paper is crucial.

Precise synchronisation for optimal results

For 4-color process printing, the four print units, stacked in the 4-Hi tower apply black, cyan, magenta and yellow inks, fed from a central inking system. “Our machine process is designed to run continuously at very high speed, creating over 36,000 impressions per hour,” says Prakash’s managing director, Saurabh Gupta.

The printed web on a 2 x 1 press is generally (2 newspaper broadsheet pages wide and one page in circumference) so in the final step in the folder, it’s cut and folded to the correct size for each publication. The folding unit can be formatted to create several folding and pagination variants, depending on the size and layout of the finished publication. Rotating blades cut the web into different streams, which fold into each other. The turner bars use a compressed air cushion to prevent damage to the printed image. The folded sheaf containing different pages is cut to a fixed-length as it leaves the folder unit of the press. The finished newspapers are laid out with a small overlap on a conveyor belt that transports them away from the press.

PPC 2100 provides maximum flexibility and performance in very small packages.
PPC 2100 provides maximum flexibility and performance in very small packages.

Robust high performance for decentralised control

Conventional web offset press systems consist of dedicated CPUs and controllers at each station or print unit of the press. The system offered by Prakash consists of one central controller and a variety of distributed I/O modules and drives to control the individual tower and folder units. The distance between the units can be around 25 to 50 meters.

A powerful Panel PC 2100 acts as the central controller, communicating over Powerlink with the decentralised stations, each featuring remote I/O modules and three ACOPOS servo drives. The real-time, deterministic Ethernet Powerlink communication network provides the company with the desired performance.

Powerlink has helped Prakash increase its system flexibility, making diagnostics and maintenance easier and at the same time, reducing the cabling effort. “We were impressed with the distributed control options B&R offers, which fit our requirements perfectly,” notes Saurabh. “Together with Powerlink, the performance, speed and precision of B&R’s ACOPOS drives is simply amazing,” he shares.

Universal tool with pre-programmed software components

“We always wanted to have a universal development tool, where we could manage all of our automation components and machine variants in a single project. With Automation Studio from B&R, we are now able to do precisely that,” says Gupta. “mapp Technology drastically reduced our development times by providing pre-programmed blocks that our software developers just have to configure. I can say that there is nothing like mapp Technology in the entire automation market,” he added.

Prakash’s developers are now able to simply drag-and-drop preprogrammed functions into place as needed. Freed from repetitive programming tasks, they can instead focus on the machine’s core functionality. This enhances software quality, improves diagnostics and reduces development time so that Prakash can get new presses to market faster.

Compact yet powerful

The Panel PC 2100 is among the most compact and high-performance PLC/HMI systems in automation. It provides Prakash with the power needed for its application, running the real-time operating system and controlling the remote drives and I/O systems. The Panel PC’s 24V power supply eliminates the need for a switched-mode power supply (SMPS). No cabling with PC mounting, fan-less operation and efficient heat dissipation all contribute to the devices’ exceptionally low failure rate in the field.

“Our entire team was fascinated by the design, compactness and performance of the Panel PC 2100,” says Gupta. “Servicing and maintaining PCs in the field has always been a major issue for us, but with the long-term availability of B&R’s Panel PCs, coupled with the advanced software features, it’s easier than ever for us to provide the best service to our customers,” he observes.

Collaboration for technology leadership

“We are happy to partner with B&R for all of our future machines,” says Gupta. “This was the first in a long list of machines that will be 100% automated by B&R. We are sure that this partnership will take us a step higher and give us a technological edge over the competition,” he assures. Specifically, Prakash plans to introduce new features for their machines, such as, remote maintenance and diagnostics and integrate additional mapp functionalities that will benefit their customers and improve their service.

Saurabh Gupta, managing director, Prakash Web Offset Pvt. Ltd.

“Our focus is on our customers and nothing runs like our web presses. We are sure that our partnership with B&R will take us a step higher and provide the technological edge against competition. We were impressed with the decentralised control options provided by B&R, which fit our requirements perfectly. Together with POWERLINK, the performance, speed and precision of ACOPOS drives is simply amazing.”

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