Measurement of web tension distribution by point source pulse excitation

Abstract

A web is a material that is produced as a continuous sheet and stored in wound roll form. Mechanics of web material handling in production, coating or conditioning, and winding operations affect web uniformity and the material stress/strain state, thus affecting roll quality. In an effort to improve all aspects of web handling procedures, much attention has been focused on acquisition and utilization of on-line web handling process information such as web tension. Tension is a quantity basic to web production and processing yet historically has been difficult to measure except in an average sense. Improvements in on-line tension measurement accuracy have foreseeable application to automated tension control systems and winder maintenance used in modern day web production/processing facilities. This paper describes a new means of noncontacting, local web tension measurement through use of a point source pneumatic excitation coupled to signal acquisition and processing schemes. Advantages of this new system include variable web excitation rate, variable system tuning for different applications, high lateral tension distribution resolution, and compact, easily serviceable transducer head assembly. This work was sponsored through the Web Handling Research Center (WHRC), an NSF funded research facility located at Oklahoma State University in Stillwater, Oklahoma.