Helix or spiral-what's the choice for pipe dies?

摘要

For multilayer products,this design principle offers outstanding advantages and in many cases provides the only solution.Extrusion dies with up to nine concentric spiral mandrel manifolds have been produced.In addition to spiral distributors of cylindrical or conical shape,die systems have been introduced for blown-film extrusion since the early 1990s with the melt distribution in a plane-so-called flat spiral,stack,or pancake dies.Such a design principle has been adapted to building pipe dies and it is increasingly used for small pipes and tubes.Since not only spirals but also predistribution channels are located in the same flat disk,we propose using the term Circular Distribution or in German:Circular-Verteilung (CV).