THE IMPLIMENTATION OF TAGUCHI METHOD ON CNC EDM AND WEDM

PROCESS

By,

KIRAN H G

RAGHUNANDAN H S

RAJESH S

VINITESH K V

PROJECT SEMINARON

VISVESVARAYA TECHNOLOGICAL UNIVERSITYBELGAUM-590018

UNDER THE GUIDANCE OF

RAMESH BABU K

PRINCIPAL-PG STUDIESGT&TC ,MYSORE

LINGARAJU K N 

ASST. PROFESSOR

DEPT OF MECHANICAL ENGINEERING

GEC,CHAMARAJANAGARA

ABSTRACT

KEYWORDS: CNC EDM, CNC WEDM, Taguchi method, DOE,

Orthogonal array

CONTENT

INTRODUCTION

DESIGN OF EXPERIMENT

TAGUCHI METHOD

EXPERIMENTRAL AND SLECTION OF PROCESS PARAMETERS

EXPERIMENTRAL OBSERAVATION

EXPERIMENTRAL RESULTS AND ANALYSIS TAGUCHI METHOD

CONCLSIONS

REFERENCES

INTRODUCTION

EDM 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

The work material is removed by a series of sparks that cause localized melting and evaporation of the material

EDNC 32H MAKINO high precision CNC EDM

EDM is mainly used to machine difficult-to-machine materials.

The electrode is made from electrically conductive material.

Dielectric fluid should be nonconductor of electricity

EDNC 32H MAKINO high precision CNC EDM

WIRE CUT ELECTRO DISCHARGE MACHINING (WEDM),

WEDM is electro-thermal mechanisms to cut electrically conductive material.

WEDM has become the essential part of many manufacturing process industries, which need variety, precision and accuracy

FA10S MITSUBISHI high precision CNC WEDM

DESIGN OF EXPERIMENT

Design of Experiments (DOE) refers to planning,

designing and analyzing an experiment so that valid and

objective conclusions can be drawn effectively and efficiently.

The input variables are called Factors and the output

variables are called Response.

THE ADVANTAGES OF DESIGN OF EXPERIMENTS ARE

Numbers of trials is significantly reduced.

Optimal setting of the parameters can be found

out.

Qualitative estimation of parameters can be

made.

Experimental error can be estimated.

Inference regarding the effect of parameters on

the characteristics of the process

DR. GENICHI TAGUCHI

Dr. Genichi Taguchi was Born in Japan, 1924. He is an Electrical Engineer and Worked during 1950’s to improve Japan’s post-WWII telephone communication system And also called Father of the

“Taguchi Method” and “Robust Engineering

HE SUGGESTED THAT THE DESIGN PROCESS SHOULD BE SEEN AS THREE STAGES

1• SYSTEM

DESIGN

2• PARAMETER

DESIGN

3• TOLERANCE

DESIGN

In this present work, the Taguchi method has been used to plan the experiments for parameter design and subsequent analysis of the data collected

PARAMETER DESIGN

Parameter design determines the most appropriate,

optimizing set of parameters identifying the settings of

each parameter which will minimize variation from the

target performance

The selection of control factors (parameters) and their

“OPTIMAL” levels

The objective is to make the

“IMPROVEMENT OF QUALITY”

The “ OPTIMAL ” parameter levels can be determined

through experimentation

INITIATING STEPS

1. PROBLEM IDENTIFICATION

2. BRAIN STORMING SESSION (Identify:-

Factors ,Factors settings , Possible Interaction ,

Objectives)

3. EXPERIMENTAL DESIGN

(Choose orthogonal arrays, Design Experiment )

4. RUN EXPERIMENT

5. ANALYZE RESULTS

6.CONFIRMATION RUNS

EXPERIMENTRAL AND SLECTION OF PROCESS PARAMETERS FOR CNC EDM

INPUT FACTORS FOR CNC EDM

1) VOLTAGE (V)2) CURRENT (I)3) PULSE ON TIME (TON)

RESPONSES MEASURED FOR EDM

1) MATERIAL REMOVAL RATE (MRR),2) MACHINING TIME

Array Selector

TABLE 1:- LEVEL VALUES OF INPUT FACTOR

Symbols Testing

parameters

Level1 Level2 Level3

A Voltage (V) 6 7 5

B Current(I) 2 3 4

C Pulse ON

time(Ton)

35 40 45

Orthogonal Arrays represent a versatile class of

combinational arrangements useful for conducting

experiments.

ORTHOGONAL ARRAYS 

The standard two level and three level arrays are:

•Two level arrays: L4, L8, L12, L16, L32

•Three level arrays: L9, L18, L27

TAGUCHI L9 ORTHOGONAL ARRAY DESIGN MATRIX IS SELECTED FROM ARRAY TABLE

Exp.

No.

Factor

1

Factor

2

Factor

3

01 1 1 1

02 1 2 2

03 1 3 3

04 2 1 2

05 2 2 3

06 2 3 1

07 3 1 3

08 3 2 1

09 3 3 2

EXP NO

PARAMETERS LEVEL

VOLTAGE

CURRENT

PULSE ON

TIME

1 6 2 352 6 3 403 6 4 454 7 2 405 7 3 456 7 4 357 5 2 458 5 3 359 5 4 40

SLECTION OF MATERIAL FOR EDM OF ALLOY STEEL(SK-5) MATERIAL HAS BEEN CONSIDER USING COPPER ELECTRODE

Dia Of Electrode : 9.4mm

EXPERIMENTRAL OBSERAVATION & CALCULATION OF VARIOUS RESPONSE FACTORS BASED ON

TAGUCHI L9 ORTHOGONAL ARRAY

EXP NO

PARAMETER LEVELS

MACHINING TIME

1In

secs

MACHINIG TIME

2In

secs

MRR 1In

mm3/sec

MRR2 In mm3/sec

VOLTAGE

CURRENT

PULSE ON

TIME

1 6 2 35 92 94 0.2008 0.1511

2 6 3 40 79 83 0.2426 0.1994

3 6 4 45 45 43 0.3281 0.3097

4 7 2 40 38 34 0.2962 0.3036

5 7 3 45 49 46 0.3321 0.3416

6 7 4 35 69 70 0.2097 0.1987

7 5 2 45 68 67 0.2434 0.2247

8 5 3 35 96 97 0.1352 0.1359

9 5 4 40 73 70 0.1864 0.1805

Taguchi's emphasis on minimizing deviation from target

led him to develop measures of the process output that

incorporate both the location of the output as well as the

variation. These measures are called signal to noise ratios.

The signal to noise ratio provides a measure of the

impact of noise factors on performance.

SIGNAL TO NOISE RATIO

There are 3 Signal-to-Noise ratios of common

interest for optimization of Static Problems

SMALLER-THE-BETTER

NOMINAL-THE-BEST

LARGER-THE-BETTER

n = 10 Log10 [ square of mean/ variance ]

NOMINAL-THE-BEST

This case arises when a specified value is MOST desired, meaning that neither a smaller nor a larger value is desirable

CALCULATION OF SIGNAL TO NOISE RATIO FOR MRR AND MT

EXP NOPARAMETER LEVELS SN

RATIO for MT

SN RATIO

for MRRVOLTAGE CURREN

TPULSE

ON TIME

1 6 2 35 36.3594

13.8276

2 6 3 40 29.1388

18.0704

3 6 4 45 29.8588

28.4448

4 7 2 40 22.0952 36.8242

5 7 3 45 27.0017

45.1361

6 7 4 35 39.8500

29.1000

7 5 2 45 39.5964

24.8895

8 5 3 35 42.7008

26.5849

9 5 4 40 30.5540

53.5758

Response Table for Signal to Noise Ratios for MT

LEVEL VOLTAGE IN

V

CURRENT IN

AMP

PULSE ON

TIME

1 37.6162 32.6788 39.6364

2 31.7912 32.9521 27.2640

3 29.6429 33.4194 32.1499

Δ 7.9733 0.7406 12.3724

RANK 2 3 1

Therefore, PULSE ON TIME has the maximum effect on MACHINING TIME

Response Table for Signal to Noise Ratios for MRR

LEVEL VOLTAGE IN

V

CURRENT IN

AMP

PULSE ON

TIME

1 35.02 25.18 23.17

2 20.11 29.93 36.16

3 37.02 37.04 32.82

Δ 16.91 11.86 12.99

RANK 1 3 2

Therefore VOLTAGE has the largest effect on MATERIAL REMOVAL RATE.

SIMILARLY (WEDM) OF AL-6061 MATERIAL HAS BEEN CONSIDER USING WEDM WITH A BRASS WIRE

ELECTRODE

Input Factors:-

Voltage (v)

Current (Ip)

Voltage gap (Vg)

Wire tension (WT)

EXPERIMENTRAL AND SLECTION OF PROCESS PARAMETERS FOR CNC EDM

Responses measured:- Machining time (MT),Cutting speed (CS)

LEVEL VALUES OF INPUT FACTORS

SymbolsTesting

parametersLevel1 Level2 Level3

A Voltage (V) 6 8 10

B Current(I) 4 7 9

CVoltage gap

(Vg)55 58 60

DWire tension

(WT)8 9 10

EXPERIMENTAL RESULTS AND CALCULATIONS OF VARIOUS RESPONSE FACTORS BASED ON TAGUCHI L9 ORTHOGONAL

ARRAY

Calculation of Signal to Noise ratio for MT

EXP NO

PARAMETER LEVELS MT1 In sec

MT2 In sec

SN RATIO

VOLTAGE (V)

CURRENT(I)

VOLTAGE GAP (VG)

WIRE TENSION

(WT)

1 6 4 55 8 12.54 12.07 31.3683

2 6 7 58 9 8.02 7.58 27.9796

3 6 9 60 10 15.20 14.54 30.0635

4 8 4 58 10 12.36 12.10 36.4588

5 8 7 60 8 6.57 6.54 49.7993

6 8 9 55 9 2.52 2.40 29.2427

7 10 4 60 9 12.46 12.01 31.6966

8 10 7 55 10 3.31 3.17 30.2966

9 10 9 58 8 3.02 2.50 17.4697

CALCULATION OF SIGNAL TO NOISE RATIO FOR CS

EXP

NO

PARAMETER LEVELS CS1In

mm/sec

CS2In

Mm/sec

SN RATIOVOLTAG

E (V)CURRENT

(I)VOLTAGE

GAP (VG)

WIRE TENSION

(WT)

1 6 4 55 8 1.3 1.32 39.3348

2 6 7 58 9 1.7 1.89 22.5043

3 6 9 60 10 0.5 1.27 3.3082

4 8 4 58 10 1.1 1.40 15.3430

5 8 7 60 8 2.9 2.46 18.6745

6 8 9 55 9 5.6 6.18 23.1335

7 10 4 60 9 1.3 1.34 33.3795

8 10 7 55 10 4.6 4.89 27.2830

9 10 9 58 8 5.4 6.10 21.2855

RESPONSE TABLE FOR SIGNAL TO NOISE RATIOS FOR MT

LEVEL VOLTAGE IN V

CURRENT IN AMP

VOLTAGE GAP

WIRE TENSION

1 29.8038 33.1745 30.3025 32.87912 38.5002 36.0251 27.3027 29.63963 26.4876 25.5919 37.1864 32.2729Δ 12.0126 10.4332 9.8837 3.2395

RANK 1 2 3 4RESPONSE TABLE FOR SIGNAL TO NOISE RATIOS FOR CS

LEVEL VOLTAGE IN V

CURRENT IN AMP

VOLTAGE GAP

WIRE TENSION

1 21.7157 29.3524 29.9171 26.4316

2 19.0503 22.8206 19.7109 26.3391

3 27.316 15.9090 18.4540 15.3114

Δ 8.2657 13.4434 11.4631 11.1202

RANK 4 1 2 3

CONCLUSION FOR CNC EDM

The MACHINING TIME (MT) mainly affected by PULSE ON TIME, VOLTAGE has less effect on it. Current (I) has a least effect on MT.

The MATERIAL REMOVAL RATE (MRR) is mainly influenced by VOLTAGE, The effect of PULSE ON TIME is less and Current has least effect on it.

Exp no. 4 is the OPTIMIZED PARAMETER for MT

Exp no. 1 is the OPTIMIZED PARAMETER for MRR

CONCLUSION FOR CNC WEDM

The MACHINING TIME (MT) mainly affected by

VOLTAGE , CURRENT &VOLTAGE GAP has less

effect on it. WIRE TENSION has a least effect on MT

The CUTTING SPEED (CS) is mainly influenced by

CURRENT, The effect of VOLTAGE GAP ,WIRE

TENSION is less and VOLTAGE has least effect on it.

Exp no. 9 is the OPTIMIZED PARAMETER for MT

Exp no. 3 is the OPTIMIZED PARAMETER for CS

REFERENCES

Abbas, N.M., Solomon, D.G., Bahari, M. F. (2007), “A review on current research trends in electrical discharge machining (EDM)”, International Journal of Machine Tools & Manufacture, 47, 1214–1228.

Adler, Yu. P., Markova, E.V., Granovsky, Yu.V. (1975),“The design of experiments to find optimal conditions”, Mir Publishers, Moscow.

Pandey P C , Shan H S, Modern Machining Processes, Tata McGraw-Hill publishing Company Limited, New Delhi, (1999).

Phadke M.S, Quality Engineering Using Robust Design, Prentice- Hall, Englewood Cliffs,NJ, (1989).

THANK YOU

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