State of the art facilities are available for manufacture of Copper Telecom Cables and Optical Fibre Cables.
The 8 mm copper wire rod is drawn down to 2.5 mm wire on high-speed, wet slip type, wire drawing machine.
Insulation is carried out on high-speed dual head extrusion lines sourced from Kobe (Japan) & Nokia Maillefer (Switzerland). Wire is drawn from 2.5 mm diameter to required size ranging from 0.4 mm to 0.9 mm. The drawn wire is annealed and preheated & then insulated uniformly with either solid HDPE / Foam Skin / Cellular / PVC insulation with or without strip or ring marking in various colors with extremely tight tolerances to help the cable meet the electrical and transmission requirements of specification.
Pairing of Insulated conductors is carried out on Group Twinners from Ceeco & Nextrom. Two insulated conductors are twisted together with an uniform lay to form a pair. The machine is capable of providing Back Twist effect on single wire during pairing operation to improve impedance stability. S-Z Oscillator unit improves high frequency performance & limits cross talk. The twisted pairs are stranded to form units of 10, 20 or 25 pairs and then wrapped helically with an identification colour binder.
The units or super units are laid up on Queins (Germany) make Drum Twisting Machine that is capable of making cable core upto 2400 pairs. It is equipped with inline facility of pumping water-resistant compound to fully fill the interstices of the laid up core. The filled core is longitudinally wrapped by polyester tape. The rotating take up provides cable lay in the range of
700 ~ 1800 mm.
Copolymer coated aluminum tape is applied longitudinally over the core wrap with overlap, which acts as an electrical screen and moisture barrier. Sheathing is carried out on Royle / Nextrom / Gauder make extrusion lines with LDPE / HDPE compound. The extruder has Fixed & Manual centering Cross Head, which offers perfect material flow distribution & excellent concentricity. The sheathing lines also have the facility for manufacture of Figure-8 Aerial Cables.
Polyethylene tape is applied helically over the inner sheath, which provides bedding for the steel tape. The cable is then helically armoured with two galvanized steel tapes with suitable overlap for imparting required mechanical protection to the cable.
A tight-fitting jacket with black polyethylene is extruded over the armoured cable. This gives mechanical protection and makes the cable resistant to ultra-violet radiation. The Jacketing lines are equipped with online diameter controllers for precise cable diameter. Marking on cables is done by either Inkjet Printers / Hot foil markers (Medek & Schroner). Extruders are equipped with Dual extrusion system for providing Single line / Dual Line identification through piggy back mobile extruder.
Colouring of natural optical fibre is carried out on Medek & Schroner make High Speed colouring line, equipped with dual UV curing chambers to ensure proper curing of UV curable inks.
Loose tube is extruded over the required number of coloured fibres on Rosendahl make secondary coating. During the extrusion process, filling gel is also pumped into the loose tube. This gel acts as a moisture barrier and provides lubrication to the fibres to counter the effects of outdoor environment. The machine has a capacity to manufacture loose tubes with upto 48 Fibres per tube. Additional rotating payoff is available to manufacture ribbon type cables.
Loose tubes are stranded around a central strength member (either metallic or non-metallic) on stranding line equipped with S-Z Oscillator. The stranded core is filled with water blocking gel and is wrapped with polyester tape. Dry Core Cables are also manufactured in which water blocking yarn or tape is used.
Rosendahl and Royle make machines equipped with online diameter controllers, for precise cable diameter, are used to sheath Optical Fibre Cables with both Multi Loose Tube and Unitube design. Armouring line from Watson, USA is provided in tandem with sheathing line for application of corrugated steel tape armouring. Aramid yarn servers are available for manufacturing ADSS Cables. Marking of cables is carried out by Inkjet Printer / Hot foil markers (Medek & Schoroner). Figure – 8 Aerial Cables are also manufactured in the sheathing line.
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