WCA March 2011

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Cable production
Wire & Cable ASIA – March/April 2011 78
Manufacturers need sophisticated and cost efficient pro-
duction equipment combined with reliable and competent
technical assistance. Growing requirements on the tech-
nological properties of data, communication and other special
cables make such equipment absolutely essential.
Niehoff offers both a wide range of modern machinery and an
immediate customer service.
The DSI stranding technology: The field-proven double
twist stranding machines of the DSI series (DSI 631 and
DSI 1001) are built for a wide conductor cross-section range
and a maximum strand diameter of 8.5mm or 15mm. The
DSI stranders available in left and right-hand versions feature
the one bow design, which results in a significantly reduced
energy consumption and noise emission. Manufacturers
benefits evolve as well from class IE2 energy-saving AC
motors with electronic control and energetically optimised
components, and a contactless machine data transfer which
minimises maintenance and
operational and material
costs.
The new machines and aux-
iliary systems comply with
the current safety regulations
of the machinery directive
RL 2006/42/EG and feature
a completely new and func-
tionally optimised machine
design.
Versatile modular system:
The DSI machines can be combined in a modular system with
double twist backtwist payoffs, longitudinal tape payoffs,
pre-twisters and other auxiliary systems. The profit is that
complete stranding lines can be customised to manufacture
all types of data and special cables, including LAN cables of
all existing – and even future – categories with the utmost
precision and quality at high speeds, either with or without
back twist.
Multi-taping, backtwisting and paring in triple twist mode
– application examples
Depending on line configuration up to three foils can be
applied in-line on a cable under controlled film tension.
One industrial multi-taping example is the production of an
instrumentation cable for the petrochemical industry. The
cable consists of two flexible conductors with polyethylene
insulation, two fillers and a drain wire.
The ALB 600 payoffs with tape
forming used in this case can be
operated with payoff spools or
film disks.
During the manufacturing in
one process, the inner part of
the cable is covered with three
film layers – a polyester film,
an aluminium/polyester film
and another polyester film –
under reduced, controlled and
homogeneous film tension. This
is done in a pre-twister which is
placed between the tape payoffs
and the DSI stranding machine.
The pre-twisters of the VVD
series have been developed for
the cost-effective production of
insulated wires, pairs, quads and
cable cores in 5 or 7-conductor
design with three or more films applied in S or Z twist direction
by double twist stranding machines. The speed can be
infinitely controlled. For certain applications, the conductors
must be backtwisted before being stranded.
The Niehoff double twist backtwist pay-off type ARD 630 D is
designed for backtwisting of single insulated conductors with
a diameter of up to 3mm, pairs and quads.
The back twist ratio can be regulated from 0 to 100% or even
higher if required. The lay length is infinitely variable from
10 to 120mm, and the number of twists is infinitely variable
up to 3,200 twists/min.
The tension is on-line controlled during the process, and the
production speed is up to 300m/min.
Optionally the double twist backtwist payoff can also
be used to enable a paring process in triple twist mode.
In this way the stranding speed and therefore the production
capacity can be considerably increased and, as a
consequence, the production costs can be reduced.
Maschinenfabrik Niehoff GmbH & Co KG – Germany
Fax: +49 9122 977 155
Email :
Website:
Double twist stranding machine DSI 631 ❍
❍
DSI 631-based special cable stranding line ❍ ❍
Double bonus from Niehoff