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.

Electrical discharge machining (EDM) is a high-precision manufacturing process that may be implemented to any electrically conductive material, notwithstanding its of mechanical residences. It’s far a non-contact process using thermal energy that is used in a wide range of applications, especially for difficult-to-cut materials with complicated shapes and geometries. The dielectric is critical in this process as it focuses the plasma channel above the processing and also serves as a debris carrier. The long-term use of dielectric used in EDM process pollutes to the atmosphere and is harmful to the operator's health. This study compares the efficiency of refined, bleached, and deodorized (RBD) palm oil (cooking oil) with traditional hydrocarbon dielectric, kerosene using copper electrode in the finishing process of AISI D2 steel. Low peak current, Ip 1A to 5A and pulse duration, ton up to 150μs were chosen as the main parameters. The effects of material removal rate (MRR), electrode wear rate (EWR), and surface roughness (Ra) were evaluated. The result shows that RBD palm oil has higher MRR which is 33.4821mm3/min while kerosene is 22.4888mm3/min, both at Ip=5A and ton=150µs. The improvement when RBD palm oil is used as dielectric is 48.88% compared to kerosene. With the increase in peak current, the EWR increases but it is inversely proportional to the pulse duration. The lowest EWR is obtained at the same IP=1A and ton=150µs for both RBD palm oil and kerosene which is 0.0010mm3/min and 0.0002mm3/min respectively. The minimum value of Ra for RBD palm oil is 2.15µm at IP=1A and ton=150µs, while for kerosene it is 2.11µm at IP=1A and ton=150µs. In terms of finishing process efficiency, RBD palm oil, a biodegradable oil-based dielectric fluid, has shown significant potential in EDM processing of AISI D2 steel.

No abstract

No abstract

No abstract