Don't Get Stressed Out Over Tension
Tension is the force acting on a web to stretch the web in the longitudinal direction, i.e., the machine direction. Web tension is always identified as the total tension across the face of the web. Determination of the correct tension for any given web on any given machine is difficult to predict. The Technical Association of the Pulp and Paper Industry (TAPPI) has determined standard tension values for paper and board stocks, and many of the companies in the field have published charts and specifications for various plastics and combinations of paper, plastic and metal foils.
Even the guidelines that do exist, however, are intended to serve as a starting point only. Their primary purpose is to enable engineers to design machines to perform specific functions on specific products. The correct tension to run is basically the least amount of tension that will allow both processing and control of the web in the machine. This can only be determined by running the web in the machine. Excess tension in the web beyond this level will create excess wear and tear on the machine components, and increase power consumption.
