## Contents

Preface vii

1 Introduction 1

1.1 Machine tool technology 3

1.2 Manufacturing systems 15

1.3 Materials technology 19

1.4 Economic optimization of machining 24

1.5 A forward look 32

References 34

2 Chip formation fundamentals 35

2.1 Historical introduction 35

2.2 Chip formation mechanics 37

2.3 Thermal modelling 57

2.4 Friction, lubrication and wear 65

2.5 Summary 79

References 80

3 Work and tool materials 81

3.1 Work material characteristics in machining 82

3.2 Tool materials 97

References 117

4 Tool damage 118

4.1 Tool damage and its classification 118

4.2 Tool life 130

4.3 Summary 134

References 135

5 Experimental methods 136

5.1 Microscopic examination methods 136

5.2 Forces in machining 139

5.3 Temperatures in machining 147

5.4 Acoustic emission 155

References 157

6 Advances in mechanics 159

6.1 Introduction 159

6.2 Slip-line field modelling 159

6.3 Introducing variable flow stress behaviour 168

6.4 Non-orthogonal (three-dimensional) machining 177

References 197

7 Finite element methods 199

7.1 Finite element background 199

7.2 Historical developments 204

7.3 The Iterative Convergence Method (ICM) 212

7.4 Material flow stress modelling for finite element analyses 220

References 224

8 Applications of finite element analysis 226

8.1 Simulation of BUE formation 226

8.2 Simulation of unsteady chip formation 234

8.3 Machinability analysis of free cutting steels 240

8.4 Cutting edge design 251

8.5 Summary 262

References 262

9 Process selection, improvement and control 265

9.1 Introduction 265

9.2 Process models 267

9.3 Optimization of machining conditions and expert system applications 283

9.4 Monitoring and improvement of cutting states 305

9.5 Model-based systems for simulation and control of machining

processes 317

References 324

Appendices

1 Metals’ plasticity, and its finite element formulation 328

A1.1 Yielding and flow under triaxial stresses: initial concepts 329

A1.2 The special case of perfectly plastic material in plane strain 332

A1.3 Yielding and flow in a triaxial stress state: advanced analysis 340

A1.4 Constitutive equations for numerical modelling 343

A1.5 Finite element formulations 348

References 350

2 Conduction and convection of heat in solids 351

A2.1 The differential equation for heat flow in a solid 351

A2.2 Selected problems, with no convection 353

A2.3 Selected problems, with convection 355

A2.4 Numerical (finite element) methods 357

References 362

3 Contact mechanics and friction 363

A3.1 Introduction 363

A3.2 The normal contact of a single asperity on an elastic foundation 365

A3.3 The normal contact of arrays of asperities on an elastic foundation 368

A3.4 Asperities with traction, on an elastic foundation 369

A3.5 Bulk yielding 371

A3.6 Friction coefficients greater than unity 373

References 374

4 Work material: typical mechanical and thermal behaviours 375

A4.1 Work material: room temperature, low strain rate, strain hardening

behaviours 375

A4.2 Work material: thermal properties 376

A4.3 Work material: strain hardening behaviours at high strain rates and

temperatures 379

References 381

5 Approximate tool yield and fracture analysis 383

A5.1 Tool yielding 383

A5.2 Tool fracture 385

References 386

6 Tool material properties 387

A6.1 High speed steels 387

A6.2 Cemented carbides and cermets 388

A6.3 Ceramics and superhard materials 393

References 395

7 Fuzzy logic 396

A7.1 Fuzzy sets 396

A7.2 Fuzzy operations 398

References 400

Index 401

## Preface

Improved manufacturing productivity, over the last 50 years, has occurred in the area of

machining through developments in the machining process, in machine tool technology

and in manufacturing management. The subject of this book is the machining process

itself, but placed in the wider context of manufacturing productivity. It is mainly concerned

with how mechanical and materials engineering science can be applied to understand the

process better and to support future improvements.

There have been other books in the English language that share these aims, from a variety

of viewpoints. Metal Cutting Principles by M. C. Shaw (1984, Oxford: Clarendon

Press) is closest in spirit to the mechanical engineering focus of the present work, but there

have been many developments since that was first published. Metal Cutting by E. M. Trent

(3rd edn, 1991, Oxford: Butterworth-Heinemann) is another major work, but written more

from the point of view of a materials engineer than the current book’s perspective.

Fundamentals of Machining and Machine Tools by G. Boothroyd and W. A. Knight (2nd

edn, 1989, New York: Marcel Dekker) covers mechanical and production engineering

perspectives at a similar level to this book. There is a book in Japanese, Modern Machining

Theory by E. Usui (1990, Tokyo: Kyoritu-shuppan), that overlaps some parts of this

volume. However, if this book, Metal Machining, can bear comparison with any of these,

the present authors will be satisfied.

There are also more general introductory texts, such as Manufacturing Technology and

Engineering by S. Kalpakjian (3rd edn, 1995, New York: Addison-Wesley) and

Introduction to Manufacturing Processes by J. A. Schey (2nd edn, 1987, New York:

McGraw-Hill) and narrower more specialist ones such as Mechanics of Machining by P.

L. B. Oxley (1989, Chichester: Ellis Horwood) which this text might be regarded as

complementing.

It is intended that this book will be of interest and helpful to all mechanical, manufacturing

and materials engineers whose responsibilities include metal machining matters. It

is, however, written specifically for masters course students. Masters courses are a major

feature of both the American and Japanese University systems, preparing the more able

twenty year olds in those countries for the transition from foundation undergraduate

courses to useful professional careers. In the UK, masters courses have not in the past been

popular, but changes from an elite to a mass higher education system are resulting in an

increasingly important role for taught advanced level and continuing professional development

courses.

It is supposed that masters course readers will have encountered basic mechanical and

materials principles before, but will not have had much experience of their application. A

feature of the book is that many of these principles are revised and placed in the machining

context, to relate the material to earlier understanding. Appendices are heavily used to

meet this objective without interrupting the flow of material too much.

It is a belief of the authors that texts should be informative in practical as well as theoretical

detail. We hope that a reader who wants to know how much power will be needed

to turn a common engineering alloy, or what cutting speed might be used, or what material

properties might be appropriate for carrying out some reader-specific simulation, will

have a reasonable chance either of finding the information in these pages or of finding a

helpful reference for further searching.

The book is essentially organized in two parts. Chapters 1 to 5 cover basic material.

Chapters 6 to 9 are more advanced. Chapter 1 is an introduction that places the process in

its broader context of machine tool technology and manufacturing systems management.

Chapter 2 covers the basic mechanical engineering of machining: mechanics, heat conduction

and tribology (friction, lubrication and wear). Chapters 3 and 4 focus on materials’

performance in machining, Chapter 5 describes experimental methods used in machining

studies.

The core of the second part is numerical modelling of the machining process. Chapter

6 deals with mechanics developments up to the introduction of, and Chapters 7 and 8 with

the development and application of, finite element methods in machining analysis. Chapter

9 is concerned with embedding process understanding into process control and optimization

tools.

No book is written without external influences. We thank the following for their advice

and help throughout our careers: in the UK, Professors D. Tabor, K. L. Johnson, P. B.

Mellor and G . W. Rowe (the last two, sadly, deceased); in Japan, Professors E. Usui, T.

Shirakashi and N. Narutaki; and Professor S. Ramalingam in the USA. More closely

connected with this book, we also especially acknowledge many discussions with, and

much experimental information given by, Professor T. Kitagawa of Kitami Institute of

Technology, who might almost have been a co-author.

We also thank the companies Yasda Precision Tools KK, Okuma Corporation and Toyo

Advanced Technologies for allowing the use of original photographs in Chapter 1, British

Aerospace Airbus for providing the cover photograph, Mr G. Dean (Leeds University) for

drafting many of the original line drawings and Mr K. Sekiya (Hiroshima University) for

creating some of the figures in Chapter 4. One of us (it is obvious which one) thanks the

British Council and Monbusho for enabling him to spend a 3 month period in Japan during

the Summer of 1999: this, with the purchase of a laptop PC with money awarded by the

Jacob Wallenberg Foundation (Royal Swedish Academy of Engineering Science), resulted

in the final manuscript being less late than it otherwise would have been.

We must thank the publisher for allowing several deadlines to pass and our wives –

Wendy, Yoko, Hiromi and Fukiko – and families for accepting the many working weekends

that were needed to complete this book.