A number of very large blown film lines have been installed recently. Davis-Standard Converting Systems in Somerville, N.J., commissioned a line last fall with an 80-in. die at Hyplast NV in Belgium for greenhouse covers and industrial films up to 65-ft in circumference. It reportedly achieves gauge tolerance of ±6%, the tightest Davis-Standard has ever achieved for such a large line. Output is over 4000 lb/hr with three extruders (one 8-in. and two 6.5-in.). A spiral die made of 4140 forged steel, not flat-rolled plate, is said to provide improved thermal stability. The massive die also has 20 heat zones, vs. the five to 10 typically found on such dies; a larger, interlocked mandrel with smaller-than-usual flare to the lip; and IBC with a reportedly unique internal and external heating mechanism to reduce melt fracture from high volumes of cold air. In May, Gloucester Engineering Co., Gloucester, Mass., shipped a similarly large line to Polytex SA in Peru for making geomembranes. It reportedly will hold ±7% or better gauge tolerance. The line probably has the world’s widest (30-ft) blown sheet winder. While large blown film bubbles are typically gusseted and folded, this 86-in.-diam. die makes a bubble 28 ft around (BUR of 1:1.5), which is slit, opened, and wound at full width onto 28-ft wide rolls. (908) 722-6000 • www.bc-egan.com (978) 281-1800 • www.gecextrusion.com
Gloucester Engineering Co.
Blackburn Industrial Park
P.O. Box 900 Gloucester, MA 01930
Phone (978) 281-1800
Editor PickSizing the Barrier Gap
Here’s a less complex way to properly size the barrier gap for barrier screws.