OPTIMIZATION OF MACHINING PARAMETERS FOR ELECTRICAL DISCHARGE MACHINING OF AUSTEMPERED DUCTILE IRON A PROJECT REPORT Submitted by K.JAYAN PRATHAP312311114048

R.KOWSIK312311114058

In partial fulfilment for the award of the degree of BACHELOR OF ENGINEERING in MECHANICAL ENGINEERING

St. JOSEPHS COLLEGE OF ENGINEERING ANNA UNIVERSITY: CHENNAI 600025 APRIL 2015 ANNA UNIVERSITY: CHENNAI 600025 BONAFIDE CERTIFICATE

Certified that this project report OPTIMIZATION OF MACHINING PARAMETERS FOR ELECTRICAL DISCHARGE MACHINING OFAUSTEMPERED DUCTILE IRON is the bonafide work of K.JAYANPRATHAP (312311114048) and R.KOWSIK (312311114058) who carried out the work under my supervision. SIGNATURE SIGNATURE

Dr.S.Arivazhagan, M.E., Ph.D. Mr. K.M.Kumar, M.E., (Ph.D)

Vice Principle and Head of the Department Associate Proffesor

Department of Mechanical Engineering, Department of Mechanical Engineering,

St. Josephs college of Engineering, St. Josephs college of Engineering,

Jeppiaar nagar, Jeppiaar nagar

Chennai-600119. Chennai-600119.

i i ix

CERTIFICATE OF EVALUATION COLLEGE NAME : St. JOSEPHS COLLEGE OF ENGINEERING BRANCH : MECHANICAL ENGINEERING SEMESTER : VIII SL.NO Name of the students who have done the Project Title of the Project Name of the supervisor with designation

1) 2) K.JAYAN PRATHAP (312311114048) R.KOWSIK(312311114058) OPTIMIZATION OFMACHINING PARAMETERS FOR ELECTRICAL DISCHARGE MACHINING OF AUSTEMPERED DUCTILE IRON Mr. K.M.KUMAR,M.E.,(Ph.D) ASSOCIATE PROFESSOR, DEPARTMENT OF MECHANICAL ENGINEERING

This report of the project work is submitted by the above students in partial fulfilment for the award of BACHELOR OF MECHANICAL ENGINEERING in Anna University and was evaluated and confirmed to be report of the work done by the above students. Submitted for UNIVERSITY VIVA EXAMINATIONS Held on:

INTERNAL EXAMINER EXTERNAL EXAMINER ACKNOWLEDGEMENT We express our sincere thanks to our Col. Dr. Jeppiaar M.A., B.L., Ph.D., our Managing Director Dr. B. Babu Manoharan M.A., MBA., Ph.D., and our Director Mr. B. Jaikumar Christurajan B.E., M.B.A, of St. Josephs college of Engineering for the help and facilities extended during the course of our undergraduate studies and materialization of this project work. We are deeply indebted to our Principal Dr.Vaddi Seshagiri Rao M.E., Ph.D., F.I.E., being a source of inspiration throughout our study in this college. We thank our Head of the department Dr.S.Arivazhagan M.E., Ph.D., and our staffs for their guidance and encouragement at each and every stage of our project work and also guiding us properly through the reviews. With profound respect, we express our deep sense of gratitude and sincere thanks to our internal guide, Mr.K.M.Kumar M.E.,(Ph.D.) for his valuable guidance and suggestion throughout this project. We express our thanks to all staff members for their kind assistance and guidance in making the project a grand success.

TABLE OF CONTENTS

CHAPTER NO TOPIC PAGE NO

LIST OF FIGURES vii

LIST OF TABLES viii

ABSTRACT ix

1 INTRODUCTION 1

1.1 Electrical Discharge Machining (EDM) 1

1.1.1 Spark Erosion Machining Process 2

1.1.2 Metal Removal Mechanism 3

1.1.3 Dielectric Fluids 6

1.1.4 Flushing 7

1.1.5 Electrode Material 9

1.2 Spheroidal Graphite Iron 10

1.2.2 Austempered Ductile Iron (ADI) 11

1.3 Heat Treatment Process 12

1.3.1 Heat Treatment of ADI 13

2 LITERATURE REVIEW 17

3 MATERIAL SELECTION 21

3.1 Workpiece Material 21

3.2 Tool Material 21

3.2.1 Copper 22

3.2.2 Brass 22

3.2.3 EN 24 23

4 HEAT TREATMENT 25

4.1 Austempering Procedure 25

4.2 Material Hardness 27

5 RESPONSE SURFACE DESIGNS 28

5.1 Response Surface Design 28

5.2 Parameter selection for EDM 29

5.2.1 Parameters Level 29

5.3. Power Supply Unit 30

5.3.1. Electrical Data 30

5.3.2. Working Parameters 30

5.4 Procedure of the Experiment 31

5.5 Material Removal Rate (MRR) and Electrode Wear 31

Rate(EWR)

6 OPTIMIZATION OF MACHINING PARAMETERS 32

6.1 ANOVA Table for MRR 34

6.1.1 Diagnostic Graph for MRR 34

6.1.2 Normal plot of residuals 35

6.1.3 Residuals vs Predicted 35

6.1.4 Residuals vs Run 36

6.1.5 Predicted vs Actual 36

6.2 ANOVA table for EWR 37

6.2.1 Diagnostic Graph for MRR 37

6.2.2 Normal plot of residuals 38

6.2.3 Residuals vs predicted 38

6.2.4 Residuals vs Run 39

6.2.5 Predicted vs Actual 39

6.3 Plot for Optimization40

6.3.1 Plot between Desirability vs Current, Pulse on 40

time

6.3.2 Plot between MRR vs Pulse on time , Current 40

6.3.6 Plot between EWR vs Pulse on time , current 41

7 RESULT AND CONCLUSION 42

LIST OF FIGURES CHAPTER TOPICPAGENUMBER

11.1 EDM CLASSIFICATION 3

1.2 EDM MACHINING 4

1.3 AUSTEMPERING TEMPERATURE AND TIME GRAPH 17

33.1 TOOL MATERIAL 26

44.1 AUSTEMPERING TEMPERATURE AND TIME GRAPH 27

4.2 AUSTEMPERED DUCTILE IRON 28

55.1 EDM MACHINE 33

5.2 CONTROL PANEL OF EDM 33

66.1 NORMAL PROBABILITY PLOT 37

6.2 RESIDUALS Vs RUN 38

6.3 RESIDUALS Vs PREDICTED 38

6.4 PREDICTED Vs ACTUAL 39

6.5 NORMAL PROBABILITY PLOT 41

6.6 RESIDUALS Vs PREDICTED 42

6.7 RESIDUALS Vs RUN 42

6.8 PREDICTED Vs ACTUAL 43

6.9 DESIRABILITY Vs CURRENT, PULSE ON TIME 44

6.10 MRR Vs CURRENT, PULSE ON TIME 45

6.11 EWR Vs CURRENT, PULSE ON TIME 46

LIST OF TABLES

CHAPTER TOPIC PAGE NUMBER

11.1 PROPERTIES OF SPHEROIDAL GRAPHITE IRON 500/7 12

33.1 COMPOSITION OF COPPER 23

3.2 COMPOSITION OF BRASS 24

3.3 COMPOSITION OF EN 24 25

44.1 AUSTEMPERING AND HARDNESS TABLE 26

55.1 PARAMETER LEVELS 31

5.2 MACHINE SPECIFICATION 32

5.3 OUTPUT VALUES OF EXPERIMENT 35

66.1 ANOVA TABLE FOR MRR 36

6.2 ANOVA TABLE FOR EWR 40

ABSTRACT The optimization of process parameters is one of the most important aspects to take into consideration in the majority of manufacturing processes and particularly in processes related to Electrical Discharge Machining (EDM) being widely used in die and mould making industries, aerospace, aeronautics and nuclear industries. Austempered Ductile Iron gives an outstanding combination of mechanical properties which include very high strength with good ductility, high fatigue strength and good fracture toughness, better vibration damping and excellent wear resistant. Through work hardening characteristics of the matrix these irons have an exceptional blend of wear properties and toughness. These properties, together with its lower density and lower production costs, have enabled ADI to replace forged steel, heat- treated steel, fabrications and aluminium components, for many applications. ADI components are used in a variety of industries worldwide, which include heavy truck and bus, light car and truck, construction and building, agriculture, mining, food and feed milling and railways. Hence its wide use and high hardness requires unconventional machining such as EDM, the optimization of process parameters for the machining of ADI will provide a more economic and efficient method in doing it. Conventional machining process on ADI results in tool wear and long machining time. The process parameters that we are going to optimize are the input current, pulse on time, flushing pressure and tool material used and analyze the output parameters such as Material Removal Rate and Electrode Wear Rate with the help of Response Surface methods of analysis to obtain the best operating parameter.