A taper tension profile maker in a converting machine

Abstract

Winding is an integral operation in almost every web handling process, and a center-wound roll is one of the suitable and general schemes in a winding system. However, improper internal stresses within a center-wound roll can cause damage such as buckling, spoking, cinching, etc. Wound roll quality and performance are known to be related to the distribution of in-roll stresses. It is therefore necessary to analyze the relationship between taper tension in the winding section and internal stress distribution within the center-wound roll to prevent winding failure. But it is hard to compensate for an undesirable winding roll shape such as starring, buckling, and telescoping. This is because the winding section is the final process in a roll to roll system and has no feedback control system to correct winding roll shape directly. A time varying tension profile and accurate control of it in a winding section is one way to shape the fail-safe in-roll stress distribution of a winding roll. In this study, a new taper tension profile making method is aimed for designing high quality wound rolls. A new method to determine the proper taper tension profile was designed by analyzing the winding mechanism which includes the stress model in center-wound rolls, nip induced tension model, relationship between taper tension profile and telescoping, relationship between taper tension type and internal stress distribution. An auto taper tension profile making method was proposed not only to optimize radial stress distribution but also to minimize lateral error (telescoping). Simulation results show that the proposed method is very useful for determining the desirable taper tension profile during the winding process and preventing defects of winding roll shape such as telescoping, starting, and dishing and so on.