- January 01, 2008, By Edward Boyle, Contributing Editor
As press manufacturers continue to introduce presses that can run faster in theory — but not necessarily in practice — it falls to the manufacturers of register controls, web guides, and other ancillary equipment to get those presses literally up to speed. “In reality, we are driven by the machine builders,” explains Paul Smith, VP of FMS, a German-based manufacturer of closed-loop control systems for web tension and web guiding equipment. “We don't necessarily drive the technology of the industry, but we adapt what we offer to meet the demands of the industry. Ultimately, it doesn't really matter what the material is, it's all about speed and, consequently, cost.”
The ability to control the web is the key to getting a press that is able to run at 1,000 fpm to actually run anywhere near its potential. So the onus oftentimes falls on the manufacturers of web handling equipment to make the converting process as “operator-free” as possible.
“Automation is generating a lot of improvement,” says Smith. “The more you can take the operator out of the decision-making process, the better that machine ultimately runs. Clearly that's what we want to do, automate the process. Whatever the process is, we're making it better. It doesn't mean we don't need operators, but it means removing them from the process decision perspective.”
Innovations in web handling can come both in new product development and in inventive ways to utilize existing technologies. Smith says equipment manufacturers are addressing improved registration by placing tension controls throughout the press rather than just at the unwind and rewind stations. While that is hardly unique, Smith says it is becoming more commonplace on all forms of web equipment.
For optimum registration, “anywhere there's an infeed, there should be a register control,” he says. “The more aspects of the machine you can control, the better off you are and, ultimately, the faster you can run.” Consequently, there are more tension zones than ever before.
“Where a machine builder historically may have done tension control off the unwind and that's it, now they're adding zones to control tension throughout the different processes: through the print head, at rewind, wherever, so there are more and more places where tension controls are used because of the need to have more control.”
Quality Still Counts
Tom Jonozzo, general manager of guiding systems for North American Mfg. Co., says the emphasis on increasing line speeds while, at the same time, reducing the number of operators has left it to the equipment manufacturers to develop the processes necessary to maintain quality. “When that happens, your web handling becomes more critical because you just can't handle variations in process like you could at slower line speeds. So, maybe where you had one guide on the process line, now you need three.”
Smith says most of the improvements in web handling are converter- rather than supplier-driven, “typically from the perspective of ‘What is required from me? Do I need to deliver more product? Do I need to deliver better product? Do I need to deliver better product and more of it?’ But some of the modifications that are required are substrate-driven, because machines that were built to run [paper] at 1,000 fpm now may be expected to run 1,000 fpm with a 2-mil film. Obviously, that's changing as well.”
Joe Connelly, product manager for Parkinson Technologies, a manufacturer of winding and web handling equipment for the nonwovens, plastics, and paper industries, says that manufacturers of web handling equipment also focus on the safety aspects of the converting process. They do so by developing equipment that minimizes operator contact with the web or reduces the size of the rolls coming off the press.
For example, Parkinson recently developed a new winder design for the contractor and consumer roll market that produces “market-ready” rolls that come off the rewinder with no further converting required. The winder includes a traversing mechanism that incorporates a hot melt glue dispenser and knife to adhere the web to the core automatically, cut the web at a specified lineal distance, and then adhere the cut end to the finished roll. Parkinson also developed a slitter that fits on the end of a plastic sheet line and cuts master rolls into 13 individual, 2.5-in. rolls.
“One of our concerns is safety,” says Connelly, “and as the machine gets faster, it's not really practical to expect the operator to cut the material while it's moving and transfer it to a new core. So we developed a machine to do that without the use of an accumulator, which is another expense that would be required if the web was stopped.”
Art & Science
Jim Ephraim, vibration monitoring product manager for Hardy Instruments, a manufacturer of process weighing, tension control, and vibration monitoring equipment, suggests there remains a blend of “art and science” involved in all aspects of web handling. In practice, an experienced operator can produce high quality using even the most basic equipment that monitors but does not control variables such as speed, tension, and temperature. But as presses become more complex, suppliers continually are striving to take the “science” out of the operators' hands. Ultimately, however, “If you can't measure it, you can't control it,” he says.
“We're not saying that you're going to replace the art,” adds Ephraim. “The art is when you're running a product and the operator says, ‘This is perfect; it looks perfect; it feels perfect.’ The science we apply is repeating that again and again. The art is developing the product; the science is repeating it. I've been in installations where you see an immediate impact on quality when they've gone from a manual system to an automated system.”
One of Hardy's most recent developments is designed to monitor vibration, a chief cause of registration issues. The Hardy Vibration Switch is a low-cost, self-contained monitoring system that can be mounted to any location on rotating or reciprocating equipment, and it sets off an alarm or shuts down the machine if excessive vibration levels are reached.
BST Promark, a manufacturer of video inspection equipment and web process controls, has developed the ekr500 series of controllers that use push buttons for fast and direct access to the controls, reducing startup and handling. The operator can monitor the status of the guiding system instantaneously as the controller provides data on critical system elements, including sensor coverage, actuator position, gain, and guiding set point. With the ekr500 as a foundation, BST has engineered a series of three “compact guides” that fit onto a wide range of machines with minimal effort. Edge or center guiding is done via single or dual infrared or ultrasonic sensors, depending on the application.
“Web guides remain an often overlooked but essential ingredient of an efficient and productive machine,” says BST general manager John Thome. “Web guides being installed today are more operator-friendly and easier to use than ever, and they provide real-time data to the operator on the status of the guiding system.”
Andy Wissenback, a district manager for Maxcess Intl., says companies in his Southern California territory are “really looking at eliminating people” and consequently investing more in equipment and upgrades that will enhance productivity. Improvements in ancillary equipment such as brakes, knifeholders, and tension controls are critical, particularly when modifying a press to handle different substrates.
Recent introductions include the all-electronic e-Knifeholder from Tidland that self-calibrates to optimize blade geometry during setup, blade overlap, and side-force; the TruWide sensor from Fife that allows operators to run multiple webs and a variety of materials without setup changes or sensor repositioning; and the MAGPOWR Smart Brake, which indicates common problems, like brake wear and overheating, before they affect product quality.
“Good companies will always invest in new equipment,” says Wissenback. “They know there's payback in doing that, but other people won't do that, and those people aren't going to be here forever. If you don't invest in equipment now, it's going to be done overseas.”
Roll Quality Overlooked
Del Carlson, project manager for Process Inc., a project management firm, says that while it may seem obvious, converters should pay particular attention to the types of materials that run on their presses, since web tension can be affected as much by the quality of the roll as by the equipment it's running on. As with meat, the center cuts of a roll of film may be the most expensive, but they deliver the most consistent quality and can improve tension control throughout the run. Odd lots are a definite no-no for anything but the simplest job.
“The very best material you can buy obviously does not come at the cheapest price point, but if you want the best film, you have to buy the center cuts,” says Carlson. “That's where you'll find the most consistent tension across the face of the material. The majority of the [converters] in the US try to buy at the best price. They don't know where it's cut from, and they certainly don't spend the time to find out what the tension is.”
Haste Without Waste
In the future, as automation plays an even bigger role in all areas of web handling, Paul Smith says that computerization — particularly the use of BUS systems to better monitor all aspects of a running machine — will improve an operator's ability to get real-time data and make instant adjustments that allow the equipment not only to run faster but with even less waste. Using the Ethernet, says Smith, converters can “move one step closer to the mythical ‘lights out factory’ where a manager can sit at his desk and see what every part of the machine is doing. But the industry still has some work to do in developing an industry standard that will allow the system to function seamlessly.
“Communication will be better, there will be less wires involved, and there will be a ‘series-ability’ about it,” says Smith. “Ultimately, [the operator] will be able to see if the load cell on roller number two on machine five is running odd, so maybe we should check the bearing on the roller. It's the ideal scenario.”
And perhaps the ultimate in efficient web handling.
Contributing editor Edward Boyle, based in Reading, PA, has covered the converting industry for more than 23 years. Contact him at EJB Communications; 610-670-4680; firstname.lastname@example.org.
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To find additional suppliers of web handling equipment on our site, click on Directories.
FMS USA | www.fms-technology.com PFFC-ASAP 307
North American Mfg. Co./Guiding Systems | www.namfg.com PFFC-ASAP 308
Parkinson Technologies | www.parkinsontechnologies.com PFFC-ASAP 309
Hardy Instruments Inc. | www.hardyinstruments.com PFFC-ASAP 310
BST Promark | www.bstpromark.com PFFC-ASAP 311
Maxcess Intl. | www.maxcessintl.com PFFC-ASAP 312
Process Inc. | www.processinc.net PFFC-ASAP 313