Proficiency of Electrical Discharge Machining in Fabrication of Microstructures
Microfeatures have a lot of applications and are widely used in medical, defense, fluidic, communication technology, micro-electromechanical system, etc., wherein machining and fabrication of miniature devices are of prime importance. Electrical discharge
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1 Introduction Electrical discharge machining (EDM) is used for precise machining of conductive materials irrespective of their strength and hardness. It removes material by melting and evaporation due to the generation of sparks between the tool and workpiece electrodes. In the EDM process, electrical energy is converted into thermal energy, which is visible in the form of a spark. The electrical sparks generate intense heat energy, which is responsible for the removal of material. A gap exists between the tool and the workpiece, which facilitates the occurrence of spark during the machining process. Thus, the process is contactless and free from the ill-effects of vibration and chatter-related problem which are quite relevant in conventional machining processes. The traditional EDM is mainly used for the machining of dies and molds, where the tip of the tool acts as the negative impression of the machined cavity. Besides, it is also used for machining of parts, complex components, intricate shape components, drilling of micro- or nano-holes, etc. But over the years, the EDM process has been P. K. Patowari (B) · S. Kar · T. Debnath Department of Mechanical Engineering, National Institute of Technology Silchar, P.O. Silchar, Assam 788010, India e-mail: [email protected] S. Kar e-mail: [email protected] T. Debnath e-mail: [email protected] A. K. Singh Department of Mechanical Engineering, National Institute of Technology Nagaland, Chumukedima, Dimapur 797103, India e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021 H. K. Dave and D. Nedelcu (eds.), Advances in Manufacturing Processes, Lecture Notes in Mechanical Engineering, https://doi.org/10.1007/978-981-15-9117-4_1
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successfully applied in different forms which can be termed as variants of EDM. The most commonly used EDM variants are die-sinking, wire-cut, block electrical discharge grinding (BEDG), milling and reverse. All these variants possess unique capabilities of fabricating a different kind of features and structures but with the same machining phenomenon. In this phenomenon, initially, the tool with specific geometry moves toward the workpiece, and resulting sparks are produced in between the tool and the workpiece in the presence of dielectric fluid. The first spark is produced at the location where the minimum distance between the electrodes is identified and breakdown occurs at the minimum resistance point. Subsequently, material is removed from both electrodes, and the discharge point shifts to a new location with the closest distance between the workpiece and tool electrode. EDM is a non-contact machining process devoid of any vibration and chatterrelated problems. This unique characteristic enables it to machine microfeatures from all electrically conductive material. But, the dimensional accuracy of machined features is affected by the tool wear, which is inevitable in any EDM variant. Proper selection of process parameters helps in minimizing
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