Experimental investigation into the anode erosion phenomenon in a DC non-transferred arc plasma torch

Anode erosion phenomenon in a DC non-transferred arc plasma torch was experimentally investigated. Anode weight loss and anode erosion position with changes in plasma current, gas-flow rate and anode length were studied. The results show that all these influences could be explained by plasma power. Anode erosion position was closely related to the structure of anode nozzle and the working conditions of plasma torch. The influence of anode arc root position and the energy flow through it on anode erosion was also analyzed. Moreover, the mechanism of anode erosion and its influence on plasma jet were studied. The results can serve as a reference for revealing the mechanism of plasma discharge, for the optimization design of arc plasma torch, and for high-quality plasma generation.

SIMULATION OF METAL TRANSFER BETWEEN CYLINDRICAL ELECTRODES AT ELECTROSPARK ALLOYING

The work is dedicated to the simulation of the processes of erosion and electrode metal transfer at coating formation by an electrospark alloying method. Anode is a cylindrical rod, and cathode – a disk. During discharge pulses the erosion takes place both in anode material, and in cathode material. The anode moves in a spiral along a cathode surface. There are calculated the coefficients of precipitation equal to the probability of metal emitted from the surface of one electrode and falling onto the surface of the opposite electrode. They are constant close to the central cathode axis, but at the anode approach to the cathode end a coefficient of anode metal precipitation on a cathode decreases, a coefficient of cathode metal precipitation on an anode increases. The rates of anode erosion and cathode weight increase when the mass ratio of eroded substance of anode and cathode increases in the course of one discharge. When this ratio is equal to 5, a coefficient of mass transfer achieves 0.8-0.9 it tells of small substance loss during its transfer between electrodes. The model developed is useful for the parameter estimate of mass transfer between cylindrical electrodes at electrospark processing taking into ac-count their dimensions and paths of anode motion.

Influence of Carbon-Protection-Film to Deterioration of Electrode in EDM

In this paper, process of how carbon-protection-film is formed and dynamic influence process of carbon-protection-film to electrode erosion are discussed in limited continuous pulse discharge. It is considered that the compensation of carbon-protection-film to anode erosion results in the cathode erosion bigger than that of the anode under long time EDM.