- Independent rotation of die and mandrel
- Increased ring stiffness and pressure resistance, reduced friction
- Applications: from PVC to PE / PP pipes with glass fiber
A tooling to produce pipes does usually not have any element which rotates, as a plastic pipe – single or multilayer – does not have any structure which requires rotation. But this has changed. The Austrian company Conextru GmbH shows that the independent turning of die and mandrel brings advantages to a number of pipe applications.
Independent rotation of die and mandrel
The technology allows the independent rotation of the die and mandrel, i.e. left or right, oscillating or both at the same time to left and right. The rotation speed can be adjusted and is usually within 0,5 and 30 RPM, depending on the application. For the basic pipe head the company uses either helical spiral or radial spiral technology (for PO pipes) or both or a combination (for multilayer pipes).
Applications: from PVC to PE / PP pipes with glass fiber
There are a number of pipe applications which feature a better performance if the pipe has an inside structure produced by rotation. For example:
- PVC pipes with spiral ribs on inside for house sewer pipes – to increase flow down on vertical installed pipes and to reduce noise
- PVC die set with a turntable die – to have an adjustable die gap by turning
- PE pipes with oscillating ribs on inside for cable ducts – to reduce friction and increase pulling through length
- PE pipes with spiral ribs on inside surface to generate turbulent flow – to increase thermal conductivity for geothermic pipes
- PE or PP pipes with filler – to bring the filler in a preferred direction in order to increase thermal conductivity
- PP pipes with hollow profile in spiral shape – to increase ring stiffness of the pipe
- PE / PP pipes with glass fiber layer in spiral shape – to increase pressure resistance
Conextru GmbH is specialized in pipe applications and supplies a wide range of mono- and multilayer die heads for pipe extrusion.