Used stranding / bunching equipment for cable production
There are several machines available to strand or bunch wires or single conductors together to assemble wire stands or cables. Following we describe some examples:
Double Twist Buncher
A double twist strander is used to bunch or twist several wires together to a strand or to bunch or twist already insulated conductors together to a more compplex composite. A double twsit strander twists the material together through a rotation stranding bow, which is rovolting around the take-up bobbin for the finished product. By doing this the material ist twisted twice per revolution of the stranding bow around the bobbin. A related principle - the single twist bunching - is a slower process, however creates usually rounder strands.
Important production parameters of double twist stranders are the size of the take-up bobbin, the revolution speed of the stranding bow and the lay-length.
With a cage strander complex cable composites are produced. For this several bobbins with the material to be stranded are mounted in big cages, which can revolt around the length axis of the stranding process. By doing so the materials are being twisted together. There are two different principles in cage stranding. One is planetary stranding, the other rigid. While planetary stranders create a torsion free strand, since the bobbins are back-twisted, rigid cage stranders don't. However for some products it does not matter if there is torsion in the prodcut (eg. wire amouring on cables).
Cage strandes are available in very different sizes and lenths. While samllest machines have only 6 pay-off bobbins of 400 mm (or even samller) diamter in one cage, bigger machines may have up to 4 cages with 6, 12, 18, 24 and 48 bobbins of up to 630 or even 1000 mm bobbin size. These are very big production facilities which require a lot of space.
Drumtwister for cable production
A drumtwister is an assembling machine for conducting one of the final steps in cable production. It is used to strand together the competed components of a cable. To do this the components (ie. sector shaped power cable conductors, or bundles of telecommunication cables) are being payed-off from either also rotating or stationary pay-offs, and then being taken-up by the drumtwister, which rotates around it's own axis while doing so. This causes the components to be stranded together. A drumtwister can also be used to amour a cable. To do this a layer of steel wires can be stranded around a finished cable construction in order to protect it against mechanical stress.
Taken all things in consideration a drumtwister is a very versatile strading machine for the cable industry.