ON THE ANALYSIS OF THE ELECTROCHEMICAL SPARK MACHINING PROCESS

The electrochemical spark machining (ECSM) process has been proved as a potential process for machining of low machinability high-strength e lectrically non-conducting materials, but the mechanism of material re moval during the process, by and large, is not yet understood. In the present work, the electrochemical discharge is modelled as a phenomeno n similar to that which occurs in are discharge valves. This phenomeno n is used to explain various experimental results, on the basis of cir cuit and are discharge valve characteristics. The spark energy and the approximate order of hydrogen gas bubble diameter are computed by the proposed valve theory. Material removal rate is evaluated by modellin g the problem as a 3-D unsteady state heat conduction problem. The pro blem is solved by the finite element method to compute the temperature distribution which is post-processed for estimating material removal per spark, overcut obtained in the machined cavity, and attainable max imum penetration depth. The conclusion drawn is that the application o f valve theory to the ECSM process seems to be realistic. Estimated ma terial removal rate, overcut and maximum penetration depth show a good agreement with experimental findings. (C) 1998 Elsevier Science Ltd. All rights reserved.