Extruder-roll tension control

A variety of AC and DC drives are available for extruders. DC motors with solid-state eontrollers and power supplies provide the most flexible seenario for control. A speed control feedback loop on the drive will minimize variation in the extruder output. The unwind roll should be equipped with a tension control device such as an electronic regulator. 

The fiber was extruded vertically downward to a nylon guide wheel (8) located about 30 cm below the die, by which point the fiber had been solidified. This guide was mounted on a force transducer to allow measurement of the tension on the fiber. The fiber was wrapped 180° around this guide wheel and directed to a second guide wheel (9) on its way to a pair of take-up rolls (10 and 11). The fiber was wound once around the take-up rolls and was next taken up by a wind-up roll (12). These rolls were 5 cm in diameter and were made of aluminum covered with tape to enhance their grip on the fiber. Only two rolls (10 and 12) were motor-driven having a maximum speed of3,600 rpm, while one roll (11) was free spinning. The maximum take-up speed was therefore about 600 m/min. The motor speed was controlled by a variable transformer (14). 

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