Advances in plasma arc cutting technology: the experimental part of an integrated approach

Plasma modeling, numerical simulation and diagnostics can be very useful tools for designing and optimizing plasma arc cutting torches and they should be used in conjunction in order to obtain significant added value from an integrated approach to design, but research is still in the making for finding a link between simulation of the plasma arc and a consistent prevision of cut quality. Diagnostics based on high speed imaging can play an important role for investigating significant phenomena, otherwise impossible to recognize. Schlieren photography can be very useful to better understand the interaction between the plasma discharge and the kerf front. Also, the behaviour of hafnium cathodes at high current levels at the beginning of their service life can be experimentally investigated, with the final aim of characterizing phenomena that take place during those initial piercing and cutting phases and optimizing the initial shape of the surface of the emissive insert exposed to plasma atmosphere. Experimental evidences can be integrated with simulative results in order to avoid a try & fail approach, often too expensive, to validate models and to identify innovative design solutions, addressing specific issues that cannot be fully investigated through experimental tests.