B. Sidda Reddy et al. 11 studied thatinfluence by design four factors such as current, servo control, duty cycle andopen circuit voltage over the outputs on MRR, TWR, SR and hardness on thedie-sinker EDM of machining AISI 304 SS. They had been employed DOE techniquewith mixed level design and analyze for performing a minimum number of runs. Theyachieved that for higher MRR, the current, servo and duty cycle should be fixedas high levels and 95% confidence level with descending order in case of TWRwith same factors. M.
M. Rahman et al. 12 experimentally foundout the machining characteristic of austenitic stainless steel 304 throughelectric discharge machining. The investigation shows that with increasingcurrent increases the MRR and surface roughness. The TWR increases with peak currentuntil 150 µsec pulse on time.
And from the results they were found for copper electrodeal long pulse on time no tool wear with reverse polarity. S.K. Dewangan 13 investigated the effect of machining parameter settings likepulse on time, discharge current and diameter of tool of AISI P20 tool steelmaterial using U-shaped copper electrode with interior flushing technique.Experiments were conducted with the L18 orthogonal array based on the Taguchimethod. Moreover, the signal-to- noise ratios associated with the observedvalues in the experiments were determined by which factor is most affected bythe Responses of Material Removal Rate (MRR), overcut (OC) and Tool Wear Rate(TWR). S.H.
Tomadi et al. 14 analyzed that effect of machining settings of tungstencarbide on the outputs such as TWR, MRR and Surface finish. Confirmation testperformed to evaluate error between predicted values and by experimental runsin terms of machining characteristics. They were found out copper tungsten tooluse for better surface finishing of the work piece. They were using full factorial DOE foroptimization and found out with greater pulse off time lesser tool wear oftungsten carbide and with current, voltage and pulse on time increment tool wearincreased.
6. SanjeevKumar et al 15 reviewed on the new uses of electrical discharge machining(EDM) process, with certain prominence on the prospective of this process forsurface alteration. Above and beyond removal of work material during machining,the fundamental nature of the process results in erosion of tool material also.Creation of the plasma passage containing of material vapors from the erodingwork material and tool electrode; and pyrolysis of the dielectric affect thesurface composition after machining and hence, its properties. Deliberate materialtransfer may be carried out under specific machining conditions by using eithercomposite electrodes or by a break up metallic powders in the dielectric orboth. In this review on the wonder of surface modification by electricdischarge machining and upcoming leanings of its applications. B.Bhattacharyya et al.
16 Experimented on EDM using the development of amathematical model based on RSM for correlating the interactive and higherorder effect on machining parameter such as peak current and pulse on time ofsurface integrity of M2 Die steel machined through analysis of EDM parameterson surface roughness, white layer thickness and surface crack density. With thedeveloped model the optimal combination evaluated for minimizing the surfaceintegrity. Puertas et al.
17 Investigated the attentionon the die-sinking EDM with an adequate selection of machining condition is themost important aspects of the machine. They were found that the impact of thefeatures of intensity, pulse on period and duty cycle over cemented carbide orhard material such as 94WC-6Co. They determine characteristics: TWR, MRR and Raby mathematical simulations will be achieved with the DOE method combined withmultiple regressions has been effectively applied to modelling for optimalmachining condition. When intensity or pulse times were increased, theroughness value also increased.
With tungsten carbide low values should be usedfor both intensity and pulse time. J.Simao et al 18 investigated work on the surface alloying of the differentwork piece on machining over EDM. In experiments powder metallurgy made tools anduse of powders suspended in dielectric liquid. Based on experimental resultsthe use of primary sintered electrodes made from tungsten carbide resulted in theformation of a uniform modified surface layer with some micro cracks and an average thickness of up to 30 µm.
7. T.M. ChenthilJegan et al 19 determines the assortment of machining settingslike peak Current, Pulse on time, Pulse off time in EDM intended for themachining of AISI202 stainless steel metal. They were using of grey relationalanalysis technique to optimizing the machining parameters MRR and SR isintroduced. The greatest nominal influence in addition to the order ofsignificance of the manageable influences to the multi performance physical characteristicson EDM machining procedure stayed determined. The results show that Dischargecurrent was the main parameter affecting the MRR.
S.Jai Hindus et al 20 done experimentations by way of the Box Behniken design.The effects show that TWR and MRR are deeply affected using Pulse on time andcurrent (A). Cylinder-shaped copper tool ensuring a dimension of diameter of 13mm is castoff to machining of stainless steel 316 L work piece.
On MRR thegreatest weighty cause was found to be Pulse on time trailed by peak current(A) and the smallest significant was gap voltage. The MRR increased linearlywith the increase in current (A). For tool wear the most significant factor wascurrent (A) followed by Pulse on time (tw) and also laterally with the increasein voltage. T.Rajmohan et al 21 experimented using design of experiment technique under L9 orthogonalarray design and considering the effect of machining parameters of EDM such as pulseon time, pulse off time , current and voltage on MRR in machining of AISI304stainless steel. For optimization they had been used signal to noise ratio andanalysis of variance to analyze the effect of the parameters on MRR and alsooptimize the cutting parameters.
M.Kiyak and O. Cak?r 22 examined that the influences of EDM settings on surfaceroughness for machining of AISI P20 tool steel. Discharge current, pulses ontime and pulse pause time are the selected parameters. They were found thatsurface roughness of work piece and tool were influenced by discharge currentand pulse time with increasing values SR increased and with lower value andhigher pulse pause time a good surface finish achieved. 8. M.S.
Reza et al 23 optimize the controlled parameters of EDM using injectionflushing type machining on multi performance characteristics using GRA method.Parameters are optimized on different Response such as MRR, TWR and SR. Forthis experiment copper tool and AISI 304 stainless steel work piece isutilized.
L18 Taguchi’s orthogonal array design planned for experiments.Selected machine settings are Ip, Ton, polarity, voltage, dielectric liquidpressure and machining depth have been taken. AshokKumar et al 24 investigated machining of EN-19 tool steel using U-shapedtubular copper tool with internal flushing by EDM. Taguchi’s L18 OA designutilized for all runs.
They found that MRR increases when current increaseswith reduction on pulse on time, TWR increases with pulse on time increment andovercut is increases with current increment. P.Srinivasa Rao et al 25 has been developed the mathematical model forpredicting die sinking EDM of AISI 304 stainless steel work piece on responsesuch as TWR, MRR, Ra and HRB using fuzzy logic modeling. A regression analysisof experimental and predicted output was performed to investigate the model.With fuzzy rule relationship was establish through experimentation to reducethe no. of runs.
9. CHAPTER 3 3.1 Objective of the Work ü The objective of the work is to investigate theeffect of machining variables viz. discharge current ,pulse on time &voltage on output performance such as MRR, TWR & SR during machining ofEN31 steel work piece in Static and Rotary EDM by using pure copper toolmaterial. ü In this work we also have to calculate the resultsof static as well as Rotary EDM.