New Screw Boosts Blown Film Output

The new double-barrier “Fusion” screw from Xaloy Inc., New Castle, Pa., initially introduced last spring for blow molding and injection molding, now is also being used for blown film.

The new double-barrier “Fusion” screw from Xaloy Inc., New Castle, Pa., initially introduced last spring for blow molding and injection molding, now is also being used for blown film. The Fusion screw has a conventional barrier section followed by a transitional section and then a second barrier section with an undulating root, which creates chaotic mixing and completes melting. Xaloy says some 20 screws have been installed on 2-in. to 6-in. film extruders. It presented the first data on their performance at Plastics Technology’s Blown Film Conference last month in Miami, Fla. The data showed higher thoughputs at lower melt temperatures. For example, a 3.5-in., 24:1 Fusion screw at 100 rpm produced 629 lb/hr of LLDPE vs. 480 lb/hr for a barrier screw with Union Carbide mixer. Melt temperature for the Fusion screw at relatively high head pressure (6200 psi) was 445 F vs. 464 F for the barrier screw with mixer.