Extrude Fiber-Optic Tube Twice as Fast as Before

A three-extruder line for HDPE fiber-optic tubing, recently built for a Danish customer by the German branch of Davis-Standard LLC, Pawcatuck, Conn., is said to double the line speeds of other tubing lines on the market.

A three-extruder line for HDPE fiber-optic tubing, recently built for a Danish customer by the German branch of Davis-Standard LLC, Pawcatuck, Conn., is said to double the line speeds of other tubing lines on the market. The line has a 75-mm-diam. “Euro Blue” main extruder, 25-mm coextruder for the inner layer of silicone-filled PE, and a 20-mm striping extruder for product coding. The line produces 5-mm OD x 4-mm ID tubing at 110 meters/min, 7-mm x 5-mm tubing at 75 m/min, and 12-mm x 10-mm tube at 55 m/min. High speeds are attributed to a coex spiral die (similar to a stack die for blown film) plus a spray-cooling ring and 12 calibrator plates in the water bath with “water stops” borrowed from high-speed wire/cable lines to minimize water loss. The die adds internal MD serrations to facilitate drawing fiber-optic strands through the tube.