The Research Of Non-transferred Laminar Plasma Cutting

Along with the development of modern cutting technology,the disadvantage that the traditional transferred arc plasma cutting equipment cannot cut non-metallic materials has become increasingly obvious.Flame cutting and laser cutting are now two main ways to cut metal and non-metallic materials.But flame cutting has relatively low accuracy,and laser cutting equipment cost much and requires high operating conditions.Under this background,this paper designed a set of non-transferred laminar plasma torch,which can be used for cutting metal and nonmetal materials.The plasma torch designed in this paper has a length of 275mm,and a diameter of 56mm,with multi-anode structure.Each electrode has an independent cooling water channel with can leads to a long service life.The cathode material is chosen as zirconium(Zr),and the working gas is compressed air.The compressed air and zirconium match well with a high arc-ignition success rate.Besides,the compressed air has the advantages of economy and pollution-free.Based on the structural design,the thermodynamic model of plasma jet was analyzed,and the related equilibrium equations are concluded.The outlet temperature of plasma torch was calculated by Matlab and draw an outlet temperature curves with different power.According to the structure parameters of plasma torch designed in this paper,combined with the principle of plasma arc-ignition,a power supply was designed.This power supply include a high-frequency and high-voltage arc-ignition circuit and a DC keep-alive circuit.This paper mainly analyzes the selection of rectifier filter circuit and the calculation of related circuit elements.The rectifier filter circuit is simulated by Simulink.In this paper,the series circuit of high-frequency and high-voltage arc-ignition circuit and DC keep-alive circuit is given and the boot sequence of arc-ignition of plasma torch is introduced.Finally,the plasma torch and plasma power supply are studied through experiments.The experimental results show that the water and air sealing performance of the plasma torch is good.The air breakdown experiment shows that the high-voltage and high-voltage circuit can breakdown a stable air gap of 1.5mm.With a flow of 2m2/h compressed air,the plasma torch can generate laminar jet with a diameter of 4mm,and a length of 25mm.In the last,the cutting experiments of metal material and simple non-metallic material are conducted with the plasma jet,which proves the practicability of non-transferred laminar plasma torch.