Secrets of a Level Process and Product, 2001 Polymers Laminations & Coatings Conference Proceedings

D. R. Roisum--We strive for a level profile across the width of our web products to improve their quality and runnability. Profile is commonly taken to mean caliper, but can also be used for basis weight, density, moisture or any other property of interest. Profile is affected by incoming raw material, web manufacturing such as die and slice lips, and web converting such as coating, laminating and printing. Unfortunately, a level profile can be difficult to obtain, in part because some processes will object to variations that are below the threshold of common measurement techniques such as scanners and laboratory bench tests.

This paper describes why we usually desire a level profile, as well as a few cases where variation may be tolerated or even desirable. It also describes the types of profile variations and their associated risks. The thrust of this paper is, however, a compilation of the means of detecting profile variations. Here, we will stress the importance of the wound roll as both a most sensitive customer and a most sensitive measure of profile variations.