Multi-layer extrusion

A patent-pending valve from Guill Tool and Engineering – the Multiflow valve – offers productivity and cost-savings benefits to manufacturers that require the extrusion of complex multi-layer tubing.

The Multiflow valve allows extruders to manufacture either three-layer or up to five-layer tubing products with the use of fewer extruders. In the three-layer configuration, the proprietary valve is designed for use with all ABA crossheads or inline dies. Using the technology, plastic or rubber material is fed from the ‘A’ extruder and divided inside the manifold in order to form both the inner and outer layers of the final product.

‘The obvious cost savings are considerable,’ said Jim Prue, Chief Design Engineer for Guill Tool. ‘For example, a manufacturer is now able to make a three-layer product by using only two extruders, saving substantially on required outlays for capital equipment.’

Manufacturers also now have the ability to change layer-wall thickness without shutting down the extruder. This compares with other common methods of varying tube wall thicknesses that require disassembling the crosshead and swapping internal flow pieces designed for each specific wall type.

The Multiflow valve also eliminates ‘dead’ areas in the manifold that would lead to degradation of the material and contamination of the tubing -a widespread problem with many ordinary designs.

Lastly, the valve allows for tubing with a wide range of wall thicknesses to be manufactured.