MACHINERY | PIPE DIES


The material is extruded through a Venus Multi


pipe head. Its spiral geometry is optimised for the latest generation of PE and PP raw materials and has been designed to have a smaller overall length, volume and operating pressure. Extra features can be added to the pipe, such as a peelable outer skin. This peelable layer, often made from modified polypropylene, protects the pipe surface against potential notches and cracks during installation. It is typically 0.6-0.7mm thick and is added by a crosshead positioned before the final cooling bath.


Above: A European pipe producer is using Tecnomatic’s Athena die head to make five-layer PE-RT and PEX pipe


producer of five-layer PE-RT and PEX pipe. Based on a radial distributor design, the Athena


die head has been modified to improve its flexibil- ity and accuracy in the distribution – which is particularly important to shape the EVOH and adhesive into very thin, uniform layers. Radial distributors do not have any dead zones or edges where material could get trapped – which makes for easier cleaning and fast assembly and disassembly. Radial spirals allow low pressure losses and high flexibility in terms of layer structure (thick or thin layers) and number of layers. At the same time, their short flow path leads to


reduced residence time and rapid material and colour changes. The line, which has a working range from 8 to


Right: Davis- Standard’s 4000AG automated crosshead is for elastomer hose applications


32mm, works at up to 60 m/min for the five-layer PEX or PE-RT, but can also work with PE pipes in two layers up to 63mm, by means of an additional Venus Multi 2 die-head. Tecnomatic has also supplied an extrusion line – which incorporates a Venus Multi pipe head – to a pipe extruder in Myanmar. Authentic Production make multi-layer pipes up to 630mm in diameter. It has previously used Tecnomatic lines to make pipe up to 1200mm diameter. The latest product uses BorSafe HE3494-LS- H PE100 high stress crack resistant (HSCR) material in the outer layer to withstand point loads and surface damage that may occur during installation. The pipe has two layers, equal to 10% and 90% of the total thickness. The outer layer is made from HSCR PE100 material, the core from standard PE100.


IMAGE: DAVIS-


STANDARD 40 PIPE & PROFILE EXTRUSION | May 2021 www.pipeandprofile.com


Corrugation crosshead Maillefer says that its multi-layer ECH 5/50 ML crosshead can extrude corrugated pipe with up to six layers. The extrusion head is typically used to make smooth tubes found in vehicle fuel lines, vapour returns and other technical fluid applications. However, some constructions call for the tube to be corrugated, to increase flexibility in tight spaces while maintaining the integrity of each functional layer. The ECH 5/50 ML adapts well to lines that incorporate corrugators, says Maillefer. “The easy-to-fit corrugation tooling on the head


provides a seamless fit to the downstream equip- ment,” said Philippe Giovangrandi, technical director at Maillefer. The head’s flexibility to make both corrugated and smooth tubes – combined with the ease of swapping layer positions – gives manufacturers a variety of choices. Mathematically, more than 100 combinations are possible with the five-layer head, while even more are possible with the six-layer version and the corrugation feature. The head accepts materials including several


types of polyamide EVOH, PVDF, ETFE, EFEP, and HDPE.


Allowing operators to prepare for the next


product run by optimising set-up and clean operations at the head makes for faster product changes, says the company. The head’s indexing feature allows layer positions to be assigned with a simple twist. The number of layers to be extruded can be reduced by using distributors that block or combine extruder flows. The head also has a


trolley support that allow easy removal of


parts, which is convenient during set-up and cleaning


operations. �


IMAGE: TECNOMATIC


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