Working Principle of ECDM

Fig 2.0: Schematic Diagram of ECDM Setup

Hello friends, this is my 2nd post about ECDM, in this post I am going to brief you about the principle of ECDM. Before going to that it's important to have a bit knowledge about the Principle of ECM and EDM.

Working Principle of ECM:

Fig 2.1: Schematic Diagram Of ECM

All of you know about the Electroplating in which two electrodes are placed in a bath containing a conductive liquid & D.C potential is applied across them, metal can be removed from the anode & deposited on the cathode, Michel Faraday discovered this and named it as Electroplating. 

Above Figure 2.1 shows the schematic diagram of ECM. In case of ECM the same principle is used in which the work piece is made anode from which the material is to be removed and the Tool is made cathode. 

An electrolyte is pumped through the small gap which is maintained between the tool & work piece. The chemical properties of this electrolyte are such that the constituents of the work material go into the solution by the electrolytic process but do not plate on the tool.

Working Principle Of EDM:

Fig 2.2: Schematic Diagram Of  EDM

EDM is the removal of materials, conducting electricity by electrical discharge between two electrodes, a dielectric fluid being used in the process. The aim of the process is controlled removal of material from the work piece. A necessary condition for producing a discharge is the ionization of the dielectric that is, splitting up of its molecules into ions & electrons. The schematic diagram of EDM process is shown in Fig 2.2.

When current is applied between two electrodes separated by a dielectric member discharge of electrons occurs from cathode to anode, at higher voltages, the electrons separated from the cathode surface collides with dielectric molecules and causes ionization, due to ionization a continuous conducting channel is formed in the inter-electrode space. Due to the liberation of energy because of discharge leads to the generation of higher temperature causing fusion or partial vaporization of the metal and dielectric fluid, the metal gets dispersed in to the surrounding of the electrodes by the explosive pressure of the gaseous products in discharge, this causes formation of tiny crater at the point of discharge. 

Working Principle of ECDM:

Fig 2.2: Schematic Diagram Of ECDM

ECDM is a process in which a non conducting material is machined by removing material through melting or vaporization by electric sparks and arcs. When a DC current is applied between the electrodes separated by a small distance(0.03 to 0.07mm)Chemical reaction takes place this causes formation of positively charged ionic gas bubbles, these bubbles forms a dielectric space around the electrodes, at an optimal voltage these gas bubbles collapses and a current of electrons generated, this results in high temperature spark, the spark erodes the material from the workpiece. The material removed gets dissolved in the electrolyte. Electrolyte provides better cooling effect. Fig 2.2 is the schematic diagram of ECDM.