The Science Behind Web Handling
The Web Handling Research Center studies the science and technology that drive web handling.
WEB HANDLING IS a science every packaging printer or converter should understand. It's applied physics that carries a continuous-roll substrate through printing and/or converting machines with the goal being a defect-free end product. The Web Handling Research Center (WHRC), based at Oklahoma State University in Stillwater, Okla., has spent the last 20 years studying this science.
The WHRC was initiated in 1986 as a National Science Foundation center with a mission "to advance the knowledge base in technologies applicable to the transport and control of continuous-strip materials through processes and machines." At the WHRC, research efforts are aimed at "establishing a fundamental understanding of the effect on web behavior or web physical properties, machine configurations, processes, and operating conditions."
Supported by 16 sponsors—including printers/converters, suppliers, brand owners, and science and technology organizations—the center offers application seminars with an eye on educating the variety of industries that use webs of flexible materials. The WHRC has hosted 25 such seminars on web handling, with one scheduled for March 19-22 at the Wes Watkins Center on the campus of Oklahoma State University.
The seminar covers tracking and steering, wrinkling and control, winding, and tension and tension control. Bruce Feiertag, adjunct professor of mechanical engineering at Oklahoma State University, will be the seminar speaker. Feiertag has more than 35 years of experience in web handling, including process development at E.I. DuPont Corp.; equipment design and manufacturing at Fife Corp.; and applied research and development at the University. He is a recognized consultant to the industry.
Technical managers, engineers, and technologists will benefit from the seminar. For more on the WHRC or application seminar, log on to http://www.engext.okstate.edu.
Read on for more on today's web handling technology, including web guides, and register and tension controls.
Vamped up tension measurement
ABB Automation
ABB has developed a series of digital tension electronics—the PFEA11X-series—to further strengthen the advantages of its Pressductor® Load cells. The Tension Electronics PFEA11X is compact and includes an integrated display with interactive menus, which guides the commissioning step-by-step in a fast set-up sequence. This eliminates the potential for making mistakes and significantly reduces the start-up time. It also offers commissioning without calibration weights; fieldbus communication via Profibus-DP, providing a scaled and zeroed tension output that's ready for use in control and monitoring; self-diagnostics; and max load memory, a maintenance tool to help identify tension extremes and causes of load cell faults.
Web guiding system
Coast Controls
Coast Controls offers web guiding systems that are custom designed for various web widths up to 120˝ (3048 mm) and operate entirely on low pressure plant air, usually between 3 to 6 psi (.21 to .41 bar). Air consumption for a typical Coast system is minimal at approximately 1.5 cfm at 5 psi (42 l/m at .34 bar). The main advantage of using the all-air system is that it is simple to use from installation to operation. Packaging converters or printing personnel do not have to contend with complicated circuitry, electronics, or hydraulic components.
Waste and time savings
eltromat electronics
The dgc_650 register control is now able to detect extremely pale transparent and metallic colors that used to require special adjustments or could not be detected at all with the RGB fiber optic scanner. The scanner, through three adapted filters, separately analyzes the red, green, and blue color spectrums of visible light to determine the filter to use for the reliable reading of register marks. The result is waste and time savings. The operator doesn't have to change the scanner sensitivity nor the angle of scanning. The scanner maintains the patented single head concept to minimize fine tuning.
Digital web guide and tension control
Erhardt + Leimer, Inc.
The new compact DRS 24 digital web guide system can be easily integrated into any machine design with or without splice table, web cleaner, and/or tension roller. This CE-approved design is the fastest guide in its class with an adjustable correction speed up to 3.5˝ per second. A variety of edge/line sensors are available to detect and position the web. The digital controls are integrated into the pivoting frame. Adjusting both the basic guide functions and system optimization is simple, thanks to the user-friendly operator panel.
Reduce waste, improve efficiency
Fife
Fife's new D-MAX Series Web Guiding Systems help improve efficiency through increased accuracy and built-in network controls. Converters know that delays in the response of a web guide, even fractions of a second, can add up to expensive waste. In response to this concern, D-MAX Series Web Guiding Systems have improved dynamic response to ensure that corrections in web alignment are achieved as fast as possible, reducing the amount of wasted material or returned rolls due to registration errors. Fife also offers an optional network version of D-MAX, a web guide controller to include a built-in Ethernet hub, providing easy access to guide-related data, or control of multiple guides from a single location.
Tension control for fast changeovers
MAGPOWR
CYGNUS Tension Control provides the ability to store multiple setups (recipes) for different materials, allowing quick changeover without re-tuning the control for each material. Built-in Ethernet, ProfiBus-DP, or DeviceNet bus protocols allow an infinite number of setups and complete control through a human-machine interface. Eliminate the process of hanging weights over the sensing roll with weightless load cell calibration. To optimize roll stability from start to finish, automatic gain compensation measures the diameter of the roll and automatically adjusts the tuning parameters for virtually any roll build ratio. Out-of-round roll compensation ensures consistent tension when the quality of the unwind roll is compromised. Taper tension features automatically reduce tension as the roll builds to eliminate roll telescoping.
Web handling technology
Martin Automatic
Martin Automatic looks at web handling in a different way in that the company sees it beginning with the unwind or splicer and ending with the rewound roll. Proper web handling principles and technology need to be applied at every point in the process. Martin Automatic focuses largely on the beginning and the end. For example, applications involving unsupported foils or lightweight films call for low-mass rollers, including ultra-thin-wall carbon fiber idlers, in the accumulator of the splicer. Slitting certain films and laminates in-line in the company's
turret rewinds requires differential or slip-core winding for proper web control.
Compact web guide controller
North American Manufacturing
North American Manufacturing's new H6421 web guide controller combines a convenient operator touch pad interface with a pulse width modulated drive in one compact package. The web guide controller operates on a 24 VDC power supply within an IP55-rated, water- and dust-resistant enclosure. Used in conjunction with SimPlex™ sensors and actuators, the web guide controller provides precise web position control for edge guide, center guide, or line-following applications. The H6421's small size—4˝ wide x 4˝ high x 4.25˝ deep—enables maximum flexibility in installation, while the keyboard lockout capability minimizes inadvertent adjustments.
New register control feature
TruColor Vision Systems
With the introduction of the new and improved TG 4000 Series model automatic web inspection system, TruColor Vision Systems, Inc. has added TruRegister as an optional upgrade feature. The TruRegister feature is used for automatic register presetting in CI presses. Using special printed register targets with each job, coupled with a data communication link to the press, the TruRegister automatically sets the colors into the desired registration. TruRegister supports jobs up to 12 colors, and automatically positions to register marks with continual auto tracking.
By Kate Sharon
Managing Editor
