Mechanical Motion Arc Breaking Mechanism Based Electrical Arc Machining Process - Subhash Gautam - Bog

The need for innovative materials grows exponentially as technology advances. In the recent past, many sophisticated materials have been developed by the research community. Metal matrix composites (MMCs) and superalloys are examples of such novel materials. Traditional machining techniques have dominated the machining of various metals and alloys, but they have proven ineffectual in shaping advanced materials. As a result, people have devised and are still developing newer machining methods called as advanced machining processes (AMPs) to address the challenges. These processes make use of cutting-edge energy sources such as thermal, mechanical, chemical, and electrochemical energy. In traditional machining processes, material is removed through shear and brittle fracture, but in AMPs, material is removed through melting and vaporisation, chemical action, electrochemical action, or brittle fracture. Electrical discharge machining (EDM) is a widely used AMP that has found a position in today's industrial and research paradigms.

EDM is a subtractive manufacturing technology that uses the thermal aspect of a spark to remove material from a workpiece. This spark occurs between the electrodes (tool and workpiece), which are both totally immersed in a dielectric fluid. Thermal energy is used in a controlled manner to develop the workpiece's required features. The schematic of an EDM system includes a workpiece and tool electrode, a pulsed power supply system, a servo mechanism, and a dielectric and dielectric supply system. The power supply generates high-frequency pulsed voltage. The servo mechanism keeps the gap/gap voltage between the electrodes at the desired level.

Both the job and the tool are entirely immersed in dielectric medium, and a pulsed voltage is applied across the electrodes. The high electric field created between the tool and the workpiece liberates free electrons from the cathode, which flow towards the anode and clash with the dielectric along the way. Ionization of the dielectric occurs, resulting in the formation of a plasma channel. In EDM, significant input process parameters are current, voltage, pulse-on time, and pulse-off time. The high pressure in the plasma channel prevents effective molten material ejection. During the pulse-off period, the plasma channel collapses, a shock wave forms, and the melted material is removed by flowing dielectric.
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