Tension disturbances in a turret winder

Abstract

Turret winders are designed to produce batches of rolls from a continuously moving web. Typically, two spindles are mounted on a turret, 180 degrees apart. The winding roll remains in the inside (winding) position until it is nearly completed. Then the nearly completed winding roll is indexed to the outside (off-loading) position as a new core moves to the winding position. At the appropriate length, the web is cut and wrapped onto the fresh core at winding position.

While most of the roll winds in steady-state, indexing and transferring to the new core subjects the winding roll to numerous motions and changing traction points resulting in tension disturbances. The motions produce macro web length changes as the lay-on roller moves, and as the turret indexes. The incoming core contacts the web as the turret indexes. The web is nipped between the core and lay-on roller prior to the cut. The final insult is the cut and transfer of control to the inside spindle. We will discuss the impact of these disturbances on tension and roll quality. Controls to mitigate these disturbances will be suggested.