Web Handling Research Center (WHRC)
The Web Handling Research Center (WHRC) at OSU is one of 52 National Science Foundation Industry/University Cooperative Research Centers. The WHRC was initiated in 1986 and is the only center of its type in the world. The term "web" is used to describe materials that are manufactured and processed in a continuous, flexible strip form. Web materials cover a broad spectrum from extremely thin plastics to paper, textiles, metals, and composites. "Web handling" involves the physical mechanics related to the running and control of continuous strip materials (webs) through web processes and machines. A primary goal of web handling is to transport the material through processes and machines without incurring defects and losses. The mission of the WHRC is to advance the knowledge base in technologies applicable to the transport and control of continuous-strip materials through processes and machines. Fundamental and generic research studies are conducted in the following areas: mechanics of winding and unwinding, longitudinal dynamics and tension control, lateral dynamics and control, out-of-plane dynamics, wrinkling, measurement of tension and wound roll stress, and special topics (air films and conveyance, slitting, runability, and drying).
Sponsors: National Science Foundation, Oklahoma Center for the Advancement of Science and Technology, Oklahoma State Regents for Higher Education, U.S. Department of Energy, Noble Foundation, Beloit Corp., Dupont, Eastman Kodak, Fife Corp., Graphics Technology, Inc., Heidleberg Harris, Hoechst-Diafoil, ICI Americas, Kimberly Clark, Mead, 3M, Mobil Chemical, Norton, Polaroid, Reliance Electric, Rexham, Sonoco Products, Valmet-Appleton, and Worldwide Converting Machinery
PIs: Karl N. Reid and numerous faculty members indicated below
The Control and Measurement of Web Rolling and Winding Air Films
The goal of this project is to develop a means to predict and control the effects of the air films between a moving web and a drive roller and between web layers being wound into a roll. Experiments have been performed measuring spanwise variations of air film height over smooth surface and grooved rollers to evaluate the project's previously developed model of grooved roller performance. It has been found that a fundamental assumption of the model is not valid and revisions are needed. Numerical predictions of the air film thickness between webs and smooth rollers have been performed for the case of infinite span webs. These computations will be extended to the practical finite span case to determine spanwise thickness variations.
Sponsor: WHRC
PI: Frank Chambers (Mechanical and Aerospace Engineering)
RAs: Arif Akhtar, Satyanarayan Kothari, and Harshitkumar Trivedi
Air Entrapment with a Force-Loaded Nip Roller
Raw products of thin materials, such as wrap foils, photographic films, and magnetic media, are made in the form of a roll, several feet in diameter and width. When such a material is wound at speeds higher than a few hundred feet per minute, excessive amounts of air can be trapped into the wound, resulting in web defects. Therefore, the winding of thin films at high speeds usually requires a roller, called a packroll, which squeezes out some air moving with the film. The main objective of this study is to obtain prediction equations for the amount of air entrapment in a winding roll pressed by a packroll. Prediction equations were obtained under the assumption that the packroll and the winding roll are two rotating rollers. These are the only equations available that account for the air compressibility effects.
Sponsor: WHRC
PIs: Frank W. Chambers, John J. Shelton, and Young B. Chang (Mechanical and Aerospace Engineering)
RA: Peter S. Townes
Air Jet Technology in Web Handling
During some manufacturing processes of thin materials, such as photographic films and magnetic media, the films must be handled without touching. Also, manufacturing of ultra-thin films requires special support and transport techniques because conventional roller supports can cause excessive stresses or scratches on the films. The goal of this study is to develop non-contact techniques for handling thin materials. An experimental study on the impingement of air jets on a flat surface has begun. Our major interest in this first stage of work is how an air jet generates pressure and friction force on the target surface. This study has various applications, which include non-contact support of thin films, lateral positioning of thin films, spreading of wrinkled films, suppression of flutter, picking up of wet papers, and stripping off liquids from the surfaces of a moving foil.
Sponsor: WHRC
PI: Young B. Chang (Mechanical and Aerospace Engineering)
RAs: Misra Deepak and Robert McManis
Dynamic Instability and Buzz at Air Turning Bars
One of the detrimental problems in air-support devices is excessive local flutter of thin films at or near the support. Local flutter problems occur unpredictably and are managed by trial and error. The objectives of this study are to find out which geometry and operating conditions cause harmful flutter problems and to know how to avoid them. Our exploratory tests show that several different types of local flutter can occur. One type of flutter is the instability of a film caused by the air flowing through the gap between the film and a rigid wall. Analyses show that the web can flutter with a certain wavelength that depends on the air velocity. Experimental verification of the theory is in progress.
Sponsor: WHRC
PIs: Peter M. Moretti and Young B. Chang (Mechanical and Aerospace Engineering)
RAs: Zeelani A. Shaik, Lei Linda Chen, and Randal Best
Out-of-Plane Dynamics of a Moving Web
Flutter induced by the drying air-flow is a recurrent problem in high-speed paper machines, limiting production and causing breaks and outages. The objectives of this project are to analyze the dynamic behavior of a web running in an air flow, to experimentally verify the analyses, and to develop design improvements which will reduce flutter damage. The mechanisms of longitudinal and edge flutter had been identified, and the threshold conditions at which detrimental flutter occurs had been determined. Motions of a web were measured, in a wind tunnel built on a web loop, by using a pair of laser-Doppler vibrometers, and the measured results were compared with the analyses. A simple method of flutter suppression had been suggested and tested at the lab. It was demonstrated that a simple flow-deflecting plate can effectively stabilize a web.
Sponsor: WHRC
PIs: Peter M. Moretti and Young B. Chang (Mechanical and Aerospace Engineering)
RAs: Krishna Vedula and Barun Acharya
Measurements on Air Bar/Web Interaction for the Determination of Lateral Stability of a Web in Flotation Ovens
Air-support ovens are widely used for non-contact drying of coated films. In some design or operating conditions, the web (film) moves sideward resulting in the contact with a wall and damage to the coating. The objectives of this study are to analyze and experimentally verify the aerodynamic forces on a web supported by an air bar, to develop analytical models of lateral instability of a web in air-support ovens, and to develop techniques of non-contact measurement of web deflection. The ground-effect theory, originally developed for air cushion vehicles, had been re-examined and applied to the flotation of flexible webs. And the theory was compared with air bar measurement data. Recently, we began to develop a method of recording web curvature by a video camera and analyzing it in a personal computer.
Sponsor: WHRC
PIs: Peter M. Moretti, John J. Shelton, and Young B. Chang (Mechanical and Aerospace Engineering)
RAs: Brigitte Busch and Anita Morgan
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