Material removal rate and machining accuracy of electrical discharge machining (EDM) of Inconel 718 using copper electrode

Abstract

Electrical Discharge Machining (EDM) is a non-contact thermal machining process capable of machining conductive and semi-conductive materials. These capabilities bring to admission of machining materials that characteristically difficult to machine such as Inconel 718 due to its ability to maintain hardness at elevated temperature. Nickel based super alloy, Inconel 718 is one of the difficult to machine material that widely used in such high temperature application. The purpose of the study is to examine the Inconel 718 machinability by applied variable parameters such as peak current, pulse duration and repetitive used of electrode. To obtain the high performance measure in EDM, the selected peak currents were high where it is from 20 to 40A while for pulse duration is from 200 to 4μs. The performance measure that being evaluated are material removal rate (MRR), surface topography and machining accuracy. This research used Copper as electrode due to its high electrical conductivity and achieved highly in MRR. With the series of repetition used of electrode, the carbon layer known as black layer will formed at the surface contact of electrode. The relationship between the parameters and performance measure were more profound through the combination of machining parameters and black layer on the electrode. At high material removal rate, the surface topography of Inconel 718 look rougher with bigger sizes of nodules and craters produced. In the case of machining accuracy, it was found that, overall diameter overcut are less than 3.47%. The result shows that, even applying high peak current and pulse duration, the results of the machining accuracy is still acceptable.

Electrode Wear Rate On Electrical Discharge Machining of Titanium Alloys (Ti-6Al-4V) At Different Peak Current and Pulse Duration by Using Modified RBD Palm Oil as Dielectric Fluids

“…The voltage within the spark gap zone growths to a point where the fluid ionizes and becomes conductive, resulting in the production and discharge of an electric pulse, which starts the process [4,5]. Many manufacturing companies are currently employing a variety of dielectric fluids, including hydrocarbon oil, mineral oil, and deionized water, among other options [6][7][8]. However, there are numerous disadvantages to the current dielectric fluid that have an impact on the environment and workers.…”

Machinability study on laser-based powder bed fusion processed hypo-eutectic aluminium alloy composite (AlSi10Mg + NbC)

“…Following the 15 BBD experiments using equation ( 1), 29 the output responses, such as MRR and TWR, were determined using equations ( 2) and (3). 30 The corresponding weight was measured before and after machining using the weighing machine (SHIMADZU, range: 0.1 mg to 200 g). Table 2 illustrates the values of MRR and TWR based on the BBD.…”

Investigation of the performance of recycled copper swarf tool electrode processed through bound powder extrusion for micromachining

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“…Since EDM is a non-contact process, the lesser TWR attributed to the pulse off time (T off : 75 μs), which affects the spark discharge between the BPE-90°electrode and AlSi10Mg, simultaneously it does not affect the MRR of AlSi10Mg. 52 The TWR value was obtained by using equation ( 2) 51 :…”