Relating Spectroscopic Measurements in a Plasma Cutting Torch to Cutting Performance

Abstract

The relationship between plasma properties and cutting performance for a plasma arc cutting system was investigated. Plasma properties such as temperature and composition were measured using spectroscopic techniques in a 200 amp oxygen plasma cutting system. In addition to the plasma properties, the symmetry of the cylindrical cutting arc was also quantified. Cutting performance was measured by analyzing the edge quality of sample cuts. The most important measure of edge quality for this study was the angle of the cut edge. Operating parameters investigated included the effect of shield gas flow and geometry changes caused by cathode erosion. The measured plasma properties are used to account for the observed increase in recommended cutting speed for different consumable designs which operated at the same current level. A strong correlation was also shown between the measured arc symmetry and the cutting performance.

Computational Analysis of a Double Nozzle Structure Plasma Cutting Torch

“…These assumptions are generally accepted by published papers [7,8,[11][12][13][15][16][17][18][19], and they all derived results which are in a good agreement with the experiment. For the nontransferred arc plasma, taking into account the Steenbeck law, arc root position makes 3D necessary.…”

“…An efficient method to avoid the double arcing is to separate the nozzle into two insulated partitions [17]. The resulting structure is called a ''double nozzle structure'' in the present paper which is different from the dual gas structure in the papers [1,2,10,16,18]. The dual gas structure is composed of a nozzle and a shield cap.…”

“…The dual gas structure is composed of a nozzle and a shield cap. For the dual gas structure, the diameter of the shield cap is larger than that of the nozzle, for example the diameters of nozzle and shield cap of the HT2000 in papers [10,18] are 2 and 4 mm, respectively, and the channel length of the nozzle is larger than that of the shield cap. For the double nozzle structure in the present paper, the diameter and the channel length of the one nozzle is equal to the other nozzle.…”

Effects of Nozzle Length and Process Parameters on Highly Constricted Oxygen Plasma Cutting Arc

“…The length and diameter of nozzle are chosen as 2.8 and 2 mm. This torch configuration is widely investigated in the previous studies [7,11,17,23,24]. The parabolic current density of Eq.…”

Cathode diameter and operating parameter effects on hafnium cathode evaporation for oxygen plasma cutting arc

“…Using this insert shape that provides for reduced deposition of the high thermionic emissivity material on the nozzle, thereby reducing nozzle wear in the torch. The results of report [6] suggested that the plasma temperature is decreased by heavy deposits of eroded cathode material on nozzle after the large crater forms in cathode, and the cut quality also decreases in case of cathode pit wears. The authors of the reports [7,8] suggested a start-up erosion mechanism by using high-speed camera imaging.…”