Experimental investigation on influence of process parameters &

magnetic field on machining characteristics of Untreated High

Speed Steel (M2) in EDM

PRESENTATION BYA.ADITYA REDDY

ABSTRACT : Electric Discharge Machining (EDM) is one of the most accurate

non -traditional machining process available for creating tiny apertures, complex shapes etc.

The objective of EDM is to get high MRR along with achieving reasonably good surface quality of machined component.

It has important machining parameters like discharge current (Ip), Voltage(v), pulse on time (Ton), pulse off time (Toff), magnetic field strength(Mf) and work time (Tw) are considered for investigation.

The effects of machining parameters such as metal removal rate (MRR), Tool wear rate (TWR), surface roughness (SR) are investigated with and without magnetic field for Untreated High Speed Steel (M2).

In this experiment,copper tool is used to machine the work piece.

EDM : It is an electro thermal non traditional machining process, where

electrical energy is used to generate electrical spark and material removal mainly occurs due to thermal energy of the spark.

WORKING PRINCIPLE :Whenever sparking takes place between two electrical contacts, a small

amount of material is removed simply as “controlled erosion through a series of electric sparks”

EXPERIMENTATION : Tool and workpiece are connected to the DC power

supply. A dielectric fluid(EDM 30) is circulated to the gap between tool and work piece.

when the current is passed across the electrodes a narrow column of spark is generated between the tool and workpiece.

optimum gap is to be maintained between the tool and workpiece.

Kinetic energy of electrons converted into heat energy from which material is removed.

WORKPIECE :Untreated High Speed Steel (M2) It is Tungsten Molybdenum High Speed Steel Composition (C-0.85, Mn-0.28, Si-0.3, Cr- 4.15, W-6.15, Mo- 5, V-1.85) Density : 8138Kg/m3

Specific Gravity : 8.14 Modulus Of Elasticity : 30 x 106 psi (207GPA)

TOOl :Copper Electrode (Circular cross-section) 99% pure Copper Good thermal conductivity Corrosion resistance Good Machinability High strength

MAGNET : Material : Ferro Ceramic Alloy Type : Ring Dimensions : OD 90mm x ID

36mm x 15mm Thk Field Strength : 0.9 Tesla

DI ELECTRIC FLUID :Dielectric Fluid : EDM-30Properties : Allowable Burn Rate: 150 Amp Specific Gravity: 0.80 @ 25° F Viscosity: 36 SSU @ 100°F (38°C) Flash Point: 200° F Dielectric Strength: 45KVfunctions of dielectric : cools down the tool & work piece Flushes away the debris Localizes the spark energy into a small cross-sectional area

OPTIMIZATION :

For the optimization of Machining parametersAnalysis Of Variance (ANOVA)Response Surface Methodology (RSM)Techniques are used

READINGS OF MACHINING :Current(amp)

Voltage(v)

Ton(ms)

Toff(ms)

Time(min)

MRR(mm3/min)

TWR(gr/min)

SR(µm)

15 40 7 7 10.246 20.6279 0.0875 5.56

15 50 8 8 14.436 15.8324 0.0388 4.92

15 60 8 8 13.60367 16.9818 0.0412 2.56

15 70 9 9 17.51667 10.9434 0.0832 5.24

20 70 7 8 14.22367 16.0688 0.1261 5

20 80 8 7 12.15433 22.8486 0.1383 4.039

20 40 9 10 15.638 15.7941 0.0501 6.08

20 60 10 9 9.671167 27.1905 0.0695 4.7

25 80 7 7 12.03417 18.7881 0.4005 5.52

25 70 8 9 11.08383 19.623 0.0505 5.4

25 60 9 7 9.516167 28.4081 0.0117 3.529

25 80 10 8 13.997 18.6115 0.1281 3.919

GRAPHS RELATED TO MRR :

GRAPHS RELATED TO TWR :

GRAPHS RELATED TO Ra :

MULTI RESPONSE OPTIMIZATION :

READINGS OF MACHINING : WITH MAGNETCurrent

(amp)Voltage(v)

Ton(ms)

Toff(ms)

Time(min)

MRR(mm3/min)

TWR(gr/min)

SR(µm)

15 40 7 7 7.35033 25.9123 0.1067 5.64

15 50 8 8 10.3648 16.7162 0.1297 5.039

15 60 8 8 12.4782 25.4068 0.0718 5.52

15 70 9 9 14.891 11.8003 0.0376 3.54

20 70 7 8 12.2988 12.2891 0.0638 2.429

20 80 8 7 10.272 17.2262 0.1309 3.219

20 40 9 10 13.5345 20.4278 0.0911 4.359

20 60 10 9 11.3367 12.5734 0.0494 2.429

25 80 7 7 12.6843 29.4502 0.1325 5.8

25 70 8 9 12.359 13.2236 0.0453 5.96

25 60 9 7 7.08167 27.2424 0.0791 4.419

25 80 10 8 14.6775 21.0137 0.0611 5.72

GRAPHS RELATED TO MRR :

GRAPHS RELATED TO TWR :

GRAPHS RELATED TO Ra :

MULTI RESPONSE OPTIMIZATION :

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