Surface Winding to Overcome the Strain Deficiency, 1990 Finishing and Converting Conference Proceedings
The strain deficiency may be defined as the percentage displacement to go from the point where layers of sheet material first touch each other to the point where compressive strain develops reasonable pressure levels in wound rolls of the material. It was discovered in testing the stress-strain response of soft newsprint and polyester plastic sheets that a fixed amount of strain could be added or subtracted from the data to improve the fit. In considering the implications for winding, where the strain offset requires some relative motion between layers to create the displacement or strain, it was realized that the surface nip provides what is needed in terms of its straining mechanism and a pressure impulse which gives the material a head start in developing interlayer pressure. The search for a better fit to the data resulted in an improved model for the compressive stress-strain equation.
Surface Winding to Overcome the Strain Deficiency, 1990 Finishing and Converting Conference Proceedi