For any application, choosing the right tension controller involves making a lot of decisions. There are pros and cons to each option on the market and understanding now those differences translated into easier and more efficient operation or increased risks of troubles and complications can be a challenge.
The Job of Tension Controllers
The role of the tension control system is to ensure that the film, paper or other material is maintained at a specific tension. This consistent tension allows the film, paper or other material to feed through the machine at a consistent rate for a consistent appearance to the film or paper. In other words, the film or paper will be free from wrinkles, creases or areas where the film is not secured or fitted.
There can be different places to mount the tension controller. Most applications will use the system at the unwind roll to ensure constant tension on the film or paper as it enters into the production equipment. In other industries, it can be used in different positions for coatings or laminates.
Open or Closed Loop
An open loop system is manually controlled. The equipment operator selects the tension and sets a specific range. The exact tension is not monitored, but if it goes outside of the range, the system can notify the operator. Some of these systems also have other types of sensors that will provide details to the operator to allow the operator to then use the brake as these variables change.
The closed loop system there is a full measurement of the tension by the tension controller. Rather than relaying information to a human operator to make machine and system adjustments, this system automatically responds and makes the adjustments.
With the closed loop system, continual adjustments are made through the system based on roll diameter, tension on the film as well as speed. All this data is analyzed by the system, and the brake is applied or released as needed to maintain the designed tension level or within a specific range.
