The basic principle for cutting interrupted structures is indirect plasma cutting with the arc burning between the electrode and the nozzle of the plasma torch in contrast to direct plasma cutting. 
When applying the Hot-Wire technology, neither the work-piece nor the nozzle is used as anode but a wire (e.g. welding wire) which is continuously fed during the cutting process. By means of this melting auxiliary or sacrificial anode, the high thermal output of direct plasma cutting can be combined with the advantages of indirect plasma cutting, i.e. cutting of non-conductive materials like fibre-glass reinforced plastics, concrete, armoured concrete, ceramics, but also glass, wired glass and textiles.
In contrast to “classic” indirect plasma cutting, the Hot-Wire technology allows to operate the plasma torch with the same high electrical output that can be achieved with direct plasma cutting. The maximum thickness of the work-piece is primarily determined by the capacity of the plasma power source and, therefore, the available energy. Hot-Wire plasma cutting has opened up another field of application – the cutting of work-pieces with interrupted structures like gratings. They are made of all kinds of materials like mild steel, CrNi-steel and aluminium and are cut with those gases and appropriate consumables which are known from plasma cutting. In contrast to oxy-fuel cutting, different contours can be cut without preheating and, therefore, without additional rotating head and regardless of direction. Also CrNi-steel and aluminium gratings which cannot be cut with oxy-fuel can be cut with this technology safely and reliably. At present, the cutting current ranges between 200 A and 300 A. Depending on cutting current, material, size of the root face and required geometry, cutting speeds of up to 1.1 m/min are possible with good results. The maximum root face that can be cut depends on the material and ranges at present between 40 mm and 50 mm. The best cutting results can be achieved if deflection of the plasma beam in the direction of the anode is avoided. This is possible by feeding the wire at an angle of less than 45° and a distance between torch and work-piece between 12 mm and 18 mm. The distance between the wire and the surface of the work-piece should be kept as low as possible; however, it is not relevant for the cutting quality. The usual working distance is between 10 mm and 30 mm. The adjustment of the distance between torch and work-piece is realised in a capacitive manner. Due to the uninterrupted arc, the load on the consumables is low and process safety is high. The first industrial applications confirm these findings. Good cutting with little rectangularity tolerance allows manifold possible applications when cutting all kinds of contours.
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