EoW July 2008

taping, armouring & sheathing of cables

Multitaping with controlled film tension

The product range of Maschinenfabrik Niehoff includes double twist stranding machines for the production of data and special cables. The product line includes tape pay offs, which are used to apply tapes of different material under precisely controlled film tension to the stranded conductor. Films are important for the design of data and special cables consisting of insulated conductors. Films reinforce the wire insulation, protect the conductors against electromagnetic interferences or prevent the adhesion of extruded jacketing material to the stranded product. The first tape film is applied before the stranded product enters the stranding machine. During the stranding process high forces act on the foils, therefore, tension control of the film is critical and essential for high quality products. A pre-twister, placed between the tape payoffs and the stranding machine, helps achieve and maintain constant and accurate tension control. Niehoff has developed manufacturing lines that address these tasks. These lines can be used to manufacture cables for industrial applications consisting of conductor pairs, three conductors or conductor quads. Over the last few years several of these lines have been successfully supplied to data cable producers in Europe. Depending on the cable construction, such lines consist of several payoffs type ATP630, three tape payoffs type ALB600 and a pre-twister type VVD180 or type VVD250.

Figure 1 ▲ ▲ : ATP630 tangential payoff

These components have the following tasks:

The ATP630 tangential payoffs with separate drive are designed for the uncoiling of high-quality cables, insulated single conductors, pairs and quads with a maximum diameter of 3mm. The payoffs are driven by a dancer-controlled spool drive with adjustable wire tension; the maximum haul-off speed is 300 m/min ( Figure 1 ). A dancer-controlled AC motor drives the ALB600 longitudinal tape payoffs with tape forming. They are designed to enable an easy and rapid film insertion and tensioning. The film tensile force is adjusted separately, and the forming tools for overlapping on the right or on the left can be quickly exchanged. The payoffs can be operated with payoff spool or film cassettes and are suitable for films with a maximum width of 40mm and a maximum thickness of 65mm. The maximum haul-off speed is 300 m/min ( Figure 2 ).

Figure 2 ▲ ▲ : ALB600 longitudinal tape payoff

Figure 3 ▲ ▲ : VVD pre-twister

The VVD pre-twisters (VVD180 and VVD 250) have been developed for the cost-effective production of insulated wires, pairs, quads and cable cores with 5- or 7-conductor design with three or more films applied in S or Z twist direction by double twist stranding machines. The pre-twist devices enable the application of tapes under a reduced, controlled and constant tension.The devices can accommodate tapesmade from all kinds of films used for the production of data and special cables. The speed can be infinitely adjusted and controlled. The VVD pre-twisters are designed to handle stranded products with a maximum diameter of 10 or 15mm ( Figure 3 ). The double twist stranding machines of the DSI series (DSI631 and DSI1001) are designed for stranding of insulated cores to twins and quadders and for the stranding of four conductor pairs to form LAN cables and other special cables ( Figure 4 ).

Figure 4 ▲ ▲ : DSI1001 double twist stranding machine

The DSI machines are built for a wide conductor cross section at a maximum stranding diameter of 8mm or 15mm and can be combined with numerous other production equipment to produce all types of data and special cables including LAN cables of all categories – current, under development and in the future – with the highest precision. Maschinenfabrik Niehoff GmbH & Co KG – Germany Fax : +49 9122 977 155 Email : info@niehoff.de Website : www.niehoff.de

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EuroWire – July 2008