Textile materials are stored on large rolls until needed. This sketch shows a continuous process unwind and festooning station concept. Once the roll being unwound is empty, the operator needs to splice another role into the web but this must be done without stopping the process downstream of the unwind station.
A festoon is used to accumulate material so that the splice can be made and new material added without stopping the process. A dancer arm is measuring tension, and when the feed roll is stopped tension will increase. The signal from the dancer arm’s position potentiometer is fed back to a tension controller that commands the QB2 to reduce pressure in the festoon cylinders to maintain the same amount of tension while the splice is made.
Once the splice is complete, the new roll starts to uncoil, tension begins to decrease and the tension controller increases the command signal on the QB2 electronic proportional valve to increase pressure on the festoon cylinders to maintain the same level of tension on the web and accumulate material in preparation for the next splice.