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EuroWire – November 2010
68
technical article
Reducing cost in
manufacturing compact
conductors using roll
form stranding
by Sean Harrington, sales and marketing manager for Ceeco Bartell Products
Abstract
The roll form stranding process combines
the advantages of two highly productive
processes, namely roll forming and double-
twist stranding. These two systems are
forged together to create one high-speed
continuous manufacturing cell. This system
not only produces compact strand at high
speeds, but also allows significant savings
to be made throughout the stranding
process, from wiredrawing all the way
through to the extrusion process.
Introduction
Recent years have presented a great
challenge to the cable industry, especially
through the current world recession
when demand for cable has reduced, in
some cases, by 50 per cent. At the same
time raw material prices and energy costs
have continued to rise. This has made
the competition between manufacturers
increasingly aggressive in terms of product
range, product quality and costs.
The aim of this paper is to present a cost
saving technological solution for the wire
drawing process. This is the use of the roll
form strander, which allows the use of a
single input diameter wire to be utilised
throughout the stranding process giving
significant process savings and advantages,
including:
Higher stranding productivity (typically
I.
40 tonne/day compact Al)
Higher productivity in wire drawing
II.
Lower drawn wire scrap
III.
Lower insulating costs
IV.
Lower capital investment
V.
Improved return on investment
VI.
Quicker set-up
VII.
Reduced work in process
VIII.
Shorter cycle times
IX.
Smaller input wire storage area
X.
75% more energy efficient than a
XI.
typical rigid strander
Process steps
Double twist
Coil payoff
Roll forming
Round
wire
Roll formed
profiles
Assembly into compact
conductor
The roll form stranding process combines
the advantages of two highly productive
processes: roll forming of shaped wire
and double twist stranding of conductors.
These two systems are forged together
to create one high-speed continuous
manufacturing cell.
This system not only produces compact
strand at high speeds, but also allows
significant savings to be made throughout
the stranding process, from wire drawing
through to the extrusion process. Round
wire is paid off from stem-type payoff
packages allowing up to 1,000kg (2,000lb)
of aluminium or 3,000kg (6,000lb) of
copper conductor material to be staged
behind the roll form strander. The stem
package allows continuous operation and
is the preferred solution for this process,
maximising productivity when the single
input wire method is an integral part of
the manufacturing process. The round
wire passes into the external roll forming
section, an integral part of the roll form
strander.
The object is to present profiled material to
the strander. The round wire is re-shaped
into the optimum format for the desired
strand construction and finished cable
size. This roll form system can be as simple
as a two-layer (1+6) construction or as
intricate as a five-layer (1+6+12+18+24)
construction. The scope of the strand
design determines the application configu-
ration; there are many different designs
available for each layer.
(a) Roll forming of the input wires. This
is achieved with a driven roll stand
shaping each wire in a layer to a
precisely designed shape.
(b) Round wire layers where a number of
round wires are closed without any
change in section.
Depending on the strand design, up to
four layers of roll forming strand may
be produced. Each roll strand is driven
individually, allowing slight changes in
speed to be made at each position to
compensate for the variances in the spiral
length.
Process steps
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