Degreasing and stress relieving of stranded wires and ropes

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 on the picture 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 used little floor space. Plasma machines can cold start in few minutes and can be stopped imminently. This avoids the lengthy heating-up and cooling-down times and associated energy costs that are symptomatic for a conventional tube furnace.

If you are interested in knowing more about Plasmait solutions, meet the company at wire & Tube Düsseldorf 2018, from 16 to 20 April, booth 10 C52-04.