EuroWire November 2015

39 / 92

News
Technology
November 2015 37
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 to lose its straightness and 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 the resulting
mechanical properties, can be achieved on a wide range
of stranded constructions and materials such as copper,
aluminium, stainless steel, plated 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:
Degreasing and stress relieving of stranded
wires and ropes