Die head for extrusion of multilayer cable sheathing - with multiple die sleeves for independent layer thickness control

摘要

A die head for applying =2 layers of concentric extruded sheathing to a cable comprises an annular chassis fitted with a coaxial static barrel and a radially adjustable extension. The barrel and the extrusion are fitted with conic annular sleeves which can be adjusted axially to define the relative thickness of extrudates passing alongside the collars. Used for applying multi-layer sheaths with layers of differing thickness, esp. where a thick intermediate layer of one material is applied between two thin layers of a different material. The layers are applied successively in a single operation requiring only one extruder per matl. used - flows being divided to obtain two layers from one material if necessary. The thickness of each layer is controlled between two collar faces, and is independent of the flow characteristics of the materials for the adjacent layers. Layer thickness and concentricity are easily controlled.