Faster Finishing

Aug. 6, 2014
For one machine builder and its commercial printer customer, advanced servo drive technology and the high-speed motion capabilities of an EtherCAT network were essential upgrades to a modular web finishing system.

On a typical day when you check your mailbox, you’re certain to find any number of direct mail pieces from companies offering products, services and special offers. Commercial printing and mailing is still big business. So it’s no surprise that with the high volume of material involved, advanced printing and finishing solutions are still being made and improved. i-Web, a global supplier of web finishing systems based in Avon, Mass., built on 30 years’ experience in system design, integration and manufacturing of custom finishing machinery to create a next-generation web finishing system for its customers. The keys to faster finishing—as well as reductions in electrical cabinet space and electrical installation time—were a Beckhoff Automation control system incorporating advanced servo drive technology and the high-speed motion capabilities of an EtherCAT industrial network.

i-Web had been quite successful implementing advanced servo drive technology in its finishing systems for much of its history, but limiting factors started to become apparent in 2008. “We learned that the servo system we used at the time was limited in the number of axes we could control individually. Plus we had to manage different fieldbus systems for I/O and motion,” says Bob Williams, i-Web’s president. “Since we manufacture very long production lines with many dozens of high-precision motion axes, the inefficiencies ultimately became too much to bear.”

This led the company to focus on developing a next-generation motion control platform with a heavy emphasis on the networking technology. The main requirement was to standardize on a one-bus system that could capably cover motion, I/O and safety, with enough available bandwidth to run all functions at the same time without performance losses. In addition, since all i-Web machines are highly modular, every individual machine module had to be “hot-connectable” and easily tested in a plug-and-play manner. The system redesign also called for easy remote service of i-Web machines, with the ability to configure and troubleshoot everything via an external connection.

“i-Web decided to implement a full system from Beckhoff, primarily because the microsecond-level performance of EtherCAT addressed all of i-Web’s networking requirements,” says Gilbert Petersen, application engineer for Beckhoff Automation. “Considering speeds that enable communication with up to 100 servo axes in 100 µs, EtherCAT gave i-Web a way out of the throughput and communication problems caused by the previous bus system.”

A theoretical limit of up to 65,535 EtherCAT devices on a single network, as well as flexible topology options, meant system size and architecture would no longer be problems for i-Web either. “The EtherCAT I/O and drive systems from Beckhoff already had the technology in place to implement the real-time communication and hot-connect capabilities that i-Web needed,” Petersen adds.

In the new i-Web finishing machines, Beckhoff AX5000 EtherCAT drives are used for motion control and programming. A range of high-performance motors are connected to the AX5000 drives, including AM3000 series servo motors from Beckhoff. This combination allows current, speed and position control commands in the finishing machines to operate with reaction times of less than half a millisecond.

“With EtherCAT and AX5000 servo drives, we have encountered no limitations on how many individually controlled axes of motion we can have in our machines,” Williams says. “Also, because the central [PC-based controller] with TwinCAT handles all the motion control, i-Web no longer has to download data sets to individual drives in the event that any need to be replaced.”
Even machine operators who aren’t automation specialists can replace a drive on i-Web machines provided they have standard electrician and maintenance skills. In the past, this was far more time-consuming and cumbersome, requiring the on-site help of specialists.

i-Web uses Beckhoff C6920 or C6930 series control cabinet industrial PCs (IPCs) for all machine lines. The TwinCAT software system (NC PTP) centrally handles all automation and motion control requirements for i-Web machinery and manages the hot-connect capabilities of the machine modules. Various panel PCs from Beckhoff are used for visualization, including the pole-mounted CP72xx series and cabinet-mounted CP67xx series. These often feature a custom design with the i-Web logo included on the panel front. The machine interface is programmed using human machine interface (HMI) software from InduSoft.

Problem-free modular machines

A key customer for i-Web is Japs-Olson—a more than 100-year-old direct mail and commercial printing company in the Minneapolis area. Japs-Olson runs a streamlined and highly automated production facility that offers inline variable imaging, postal optimization, full-service intelligent mail barcode, freight efficiencies and JO Smartmail tracking. Japs-Olson requires a high degree of technological innovation in its machinery because the company specializes in highly customized direct mail and commercial print solutions in a range of formats that often must be printed with same-day service. Examples include folding mailers with high-quality UV coatings, highly functional “Snap Pak” envelopes, mailers with die-cut cards and more.

i-Web web handling machinery is primarily used at Japs-Olson for inline finishing of paper products (folding, cutting, stacking). “The flexible machine design and heavy use of advanced servo drive technology cement the partnership between i-Web and Japs-Olson,” says Michael Murphy, president of Japs-Olson. “Since i-Web machines provide problem-free modularity when making production changes, we can more easily create high-quality print solutions with maximized product throughput.”

There are currently three large i-Web systems in place at Japs-Olson, and a new line was scheduled to be installed in June 2014. “Japs-Olson continues to implement next-generation i-Web inline finishing systems because of the progressive use of automation technology and easy configuration on the plant floor. We harness this technological momentum in order to deliver better products and more tightly integrated services for our clients,” Murphy says.

Advanced motion and safety

During print production on an iWeb machine, the web of paper or film is transported through the machine via multiple pull rolls that all have direct-drive motors which must run synchronously. Additional equipment such as die cutters, perforators, gluers and cutters must stay in perfect sync with the finishing process. Furthermore, there are many stepper motors used to move turn bars, compensators, digital print heads, etc. To control these elements, i-Web uses Beckhoff EL7031 and EL7041 EtherCAT terminals; these are I/O terminals that function as ultra-compact drives for fully integrated stepper motor control.

In the area of safety technology, i-Web implements e-stops, safe stop functions, guard interlocks and other safety equipment on its lines using TwinSAFE and Safety over EtherCAT technology from Beckhoff. “Through the use of TwinSAFE I/O terminals distributed along our machine lines, i-Web has been able to implement significantly more safety technology,” Williams says. “TwinSAFE also provided maximum flexibility using the existing EtherCAT network in the production line, rather than having to implement a dedicated safety network.

Since the modular units can be linked into and out of the line, the safety of every module must be handled individually. If, for example, a member of the plant staff inadvertently caused an “open guard” condition, TwinSAFE technology ensures that the system stops safely in a controlled way and human safety is not jeopardized. The safe states can be triggered for a particular module, zone, or an entire line if necessary.

The standard connectivity options offered by EtherCAT and PC-based control fulfilled i-Web’s requirement to add full remote access for troubleshooting and maintenance. “Ultimately, a PC-based automation system made it a breeze for i-Web to remotely connect from outside without having to travel to each customer’s site,” says Williams. “Also, since we converted all machine communication to EtherCAT, essentially every component in the system can be monitored remotely since we heavily leverage standard Ethernet connectivity throughout the line.”
Today, more than 250 i-Web systems, in the field or in development, are EtherCAT-enabled and equipped with a Beckhoff controls architecture. As a result, Williams says, “there has been at least a 50 percent reduction in the time required for troubleshooting since moving to EtherCAT and applying remote maintenance systems. We are able to communicate to any auxiliary or plant production system without complex secondary infrastructure. Also, EtherCAT inherently includes a great wealth of diagnostic functions, such as breaking point detection, and there are no bandwidth limitations.”

Through the use of centralized control and distributed I/O technologies, i-Web also achieved substantial improvements in machine footprint size, as well as installation and testing time. “Required electrical cabinet space has dropped by 50 percent,” Williams says. “In terms of the automation and controls equipment, there has been an impressive 75 percent reduction in time required for electrical installation in the field. During final install, we only have to run power, air and one standard EtherCAT cable between machine modules. Today, we can focus more time and efforts on finalizing application programming to perfectly suit each customer’s needs.”

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