WIRE/CABLE MANUFACTURING PROCESS

WIRE/CABLE MANUFACTURING PROCESS

What are the steps/procedures in manufacturing wires/cables?

Copper and aluminum rods undergo several stages of processing beforethey become wires and cables. Below are the processes in manufacturing conductors arranged in order.

Drawing

Drawing is the process of pulling thecopper or aluminum rods or wires at normal temperature through a die to reduce the cross-sectional area in order to get the desired dimension. The wire is deformed due to the tapering of the die and the force exerted during pulling.

Annealing

Annealing is the processof "softening" the temper of the wires and improving its cold working properties and machinability through sustained heating at a pre-determined temperature followed by coolingat a defined rate.There are many ways of annealing a wire; the most common practices in annealing copper is the continuous strand or resistance annealing wherein annealing is done by means of a machine placed between the final capstan of a drawing machine and the spooler so that the wire is drawn, annealed and spooled in one preparation.

Stranding

Stranding is the process where a number of hard or soft wires are laid together geometrically in such way that each wire holds its place in the strand all throughout the entire length. Generally, the number of wires in a strand is 7, 19, 37, 61, and coul reach up to 91, 127, or 168 depending on the desired size or cross-sectional area of the stranded wire. The lay of multi-layered stranded wires are laid in opposite direction alternately in its succeeding lay with the outermost generally being left-handed.

Bunching

Bunching is similar to the stranding process except that all individual wires are twisted uniformly in the same direction without regard for geometrical arrangement. It provides a more flexible conductor than a single strand. A number of bunches twisted together in the same direction and in uniform manner is called a compound bunch. A number of bunchestwisted together so that each bunch,except the central one, hasahelical form of pre-determined lay ratio is a stranded bunch. A number of stranded bunches twisted together so that each stranded bunch, except the central one, has a helical form of pre-determined ration iscalled a compound strand bunch.

Extrusion

Extrusion is the process where an insulation material iscontinuously coated or applied around the conductor as it passes through adie in the head of an extrudingmachine. The insuation material inform of pellets, dice and the likes(an be plastic, nylon, rubber, etc.) are placed in ahopper that is situated over a barrel in which a screw revolves. The insulation material softens as it feeds inside the heated extruder barrel then melted out over the core material through the screw which forces the material along the barrel and compresses it at the same time to convert the material into fluid mass. The conductor emerges from the tip of the core with the material stream inside the extruder head and the insulation isformed to the required size and shape as the insulated conductor passes through the die.