International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 10 Issue: 08 | Aug 2023
p-ISSN: 2395-0072
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Experimental Study of Static and Rotary Electrode on Electrical Discharge Machining (EDM) using Graphite Electrode Raj Pratapa and Dr. S.K.S. Yadavb (a) M.Tech. , Department of Mechanical Engineering, HBTU Kanpur, Uttar Pradesh India (b) Associate Professor, Department of Mechanical Engineering, HBTU Kanpur, Uttar Pradesh India -------------------------------------------------------------------------***-----------------------------------------------------------------------Abstract: Electro-discharge machining is a machining process that is most widely used for machining different types of hard materials, especially electrically conductive materials. Electrical discharge Machining produces a complex profile that is not possible by traditional machining processes. In the electro-discharge machining process, the w/p and electrode both must be electrically good conductive. Graphite, copper and brass are mostly used for making the electrode due to high electrical conductivity. In this paper, a Graphite electrode used for machining of Copper Nickel alloy (grade Cu70Ni30) with a stationary and rotary electrode and analysed the MRR, Ra and TWR and compared the MRR, Ra and TWR between the static electrode and rotary electrode. In this research paper, the value of the discharge current changed during the experiment and study the consequence of the discharge current on MRR, Ra and TWR in both conditions (static and rotary electrode).
Key-words : EDM, Static and Rotary Electrode, Graphite Electrode, MRR, TWR, Ra 1. INTRODUCTION When a spark is generated between two electrically conductive materials then a small amount of material removed from the w/p and if the w/p and tool both submerge into the dielectric then it localised into a small portion which is can be controlled by various methods used This technique for machining the varies hard materials which are not possible to machining by traditional machining process. In electrical discharge machining, short-duration spark and high frequency are used for good machining and it is suitable for obtaining a good surface finish. In the EDM dielectric sparks can be concentrated into small areas and due to this meter machining is possible[1]. Electro discharge machining is one of the best machining processes for machining very hard materials because EDM is a non-contact machining process in which the tool and w/p never touch each other during the machining, when high voltage which is in pulse form and low current is applied on small electrode gap (10 μm to 70 μm) which is submerged in dielectric then very high thermal energy having spark generates which melt the material and vaporise and this process continue when pulse on and pulse off respectively. When the pulse is off, the removed material is flushed out by the dielectric fluid which flows on the machining surface with high pressure [2]. In electrodischarge machining electrical energy is transformed into thermal energy. When the spark is generated between the electrode and w/p then high energy is released which localised a small area due to the high energy w/p’s surface melt and vaporise and machining takes place. High heat energy is released when a spark is generated at approximately 8000 to 12000 degrees Celsius [3-4].In the EDM when material removes then a small portion of the material from the electrode is also removed which is called Tool wear sometimes this material is deposited on the w/p and this is called modification of electro-discharge machining surface which increases the w/p material wear and erosion resistance [5-6]. In the EDM, the electrode is called a tool, and when machining takes place, a replica of the tool (electrode ) design is obtained on the w/p. In the EDM any electrical conductive material with any type of mechanical properties like hardness, strength, modulus of elasticity etc having materials can be machined very easily. For machining any type of material by the EDM process, only two important properties are required: first electrical conductive and second thermal conductive and other mechanical properties are not important. All new advance materials and alloys which have better electrical and thermal properties can be machined by the EDM process very easily which is not possible to machine by another machining process. [7-8]. Nowadays, many companies, particularly those that make moulds and dies, submarine, ship, automobile and aerospace industries all use the EDM process for machining advanced alloy materials [9]. In the EDM process tool material and its mechanical properties play a very important role. For good and accurate machining, choosing electrodes with excellent electrical and mechanical properties is essential. The selection of electrode depends on the mechanical properties of the w/p material and based on the required surface finish, MRR[10]
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