Nordson Corporation designs new Xaloy for Polyethylene Technology

Nordson Corporation has designed a new Xaloy screw designed to put an end to a long series of troubles on a pipe extrusion line that had defied numerous attempts at a solution.  

The line, operated by diversified pipe manufacturer Polyethylene Technology, would exhibit wide fluctuations in throughput caused by surging and, for heavy-wall HDPE pipe, consistently exhibited variation from the target wall thickness of 0.097 in (2.46 mm). 

Brad Williams, senior manufacturing manager, explained: “We tried all sorts of solutions. We looked for problems with the motor drive and the puller, tested four or five alternate resins, and finally got a new screw and relined barrel—all with no success. Our gravimetric extrusion control showed fluctuations occurring every five or ten seconds.”

The company says another problem with the extrusion line was poor mixing of carbon black, whose required addition level was 2 per cent.

Polyethylene Technology turned to Nordson within months of receiving the screw from another supplier.

Brad Casale, Nordson regional sales manager, said: “We recommended our Xaloy Efficient barrier screw with a Nano mixer in the metering section. By preventing premature break-up of solids and increasing melting rates, the Efficient screw has enhanced mixing and increased throughput in the Polyethylene Technology extrusion line. The Nano mixer has provided intensive dispersionary mixing of the carbon black.”

“As a result of using the new Xaloy screw, our target output rate has increased by 12 per cent.”