EuroWire Sept 2015

41 / 108

News
Technology
September 2015 39
Degreasing of stranded wires and ropes
▲ ▲ The plasma machine allows for an accurate distribution of heat/temperature throughout the cross-section of the stranded construction
Rope and strand making often requires the individual wires to
be properly lubricated before stranding. During stranding the
individual wires also work-harden, which makes the strand lose
its straightness and causes individual wires to “flower” when the
strand is cut.
Often the strands and ropes have to be cleaned and/or stress
relieved before they are suitable for further processing or
packing. This is common in many applications, for example in
strands and ropes for the medical, jewellery, architectural and
decorative sectors.
Plasmait has been working with wire manufacturers in these
sectors to design an effective solution for heat treatment of
stranded products and ropes. The plasma machine allows for
an accurate distribution of heat/temperature throughout the
cross-section of the stranded construction.
Individual wires are annealed or stress relieved to equal temper/
softness, which straightens the strands and prevents the
“flowering” of strand ends. Accurate control of heat transfer and
thereby resulting mechanical properties can be achieved on
a wide range of stranded constructions and materials such as
copper, aluminium, stainless steel, plated wire wires and many
other materials and their alloys.
The annealing/stress relieving process is conducted in a
controlled inert atmosphere in low vacuum, which facilitates
effective degreasing inside the stranded construction during the
annealing process. This is a result of a distinct feature of plasma
discharge that is the strongest in the small cavities between the
individual wires in the stranded construction. Surface activation
can be achieved if extra coating adhesion is necessary in-line
with subsequent polymer coating.
Plasma machines can be used on a wide range of diameters
and materials. They are compact machines that use little floor
space. Plasma machines can cold start in a few minutes and can
be stopped immediately. This avoids the lengthy heating-up
and cooling-down times and associated energy costs that are
symptomatic of a conventional tube furnace.
Plasmait GmbH – Austria
Website: