Mechanics and Dynamics of Web Motion between Spans

Many factors affect the web as it travels through processing machinery, causing undesired lateral motion, trim removal problems, wrinkling, and tension fluctuations. Possible causes for these disturbances are identified, such as problems at the unwind, problems in the web material itself, the carrying rolls and their alignment, the motion of the surrounding air, and upsets due to operations performed on the web: slitting, winding, or printing, for instance. The paper presents contrasts between the assumptions of ideal geometry and what really exists in practice, to allow isolation of the various causes and effects.