An experimental study of the oxygen plasma jet of an OCP 150 cutting torch marketed by Air Liquide is presented. A fast CCD camera is used to visualize the shock wave geometry at the nozzle exit. Optical emission spectroscopy techniques are used to determine the temperature, the electron number density, the pressure and the fraction of nitrogen in the plasma jet between the nozzle exit and the anode. Measurements are performed in a real cutting configuration and compared with the results of a rotating anode device. The influence of several cutting parameters (voltage, torch velocity and plasma producing gas injection pressure) on the macroscopic properties of the arc is dealt with.

A study of arc–material interaction and energy transfer in the case of plasma cutting is presented. A fast CCD camera moving with the torch is used to estimate the anodic arc root location inside the kerf. Temperature measurements on the cut-front surface and on the kerf edges are performed by infrared pyrometry. Temperature fields inside the workpiece obtained with inserted thermocouples are compared with the theoretical results of an analytical model to estimate heat conduction losses QHCL (W) dissipated in the plate. For various sets of operating parameters (voltage, inlet oxygen pressure and cutting speed), a complete energy balance of the process is performed with the calculation of the device efficiency on the basis of the various power terms implicated in the cutting tool: the power lost above the workpiece, heat conduction losses, the power involved in melting steel, the energy released by chemical oxidation reactions, the power available for cutting and losses under the plate in the extinguishing plasma.