SECOND EDITION Fundamentals of Machining Processes Conventional and Nonconventional Processes Hassan Abdel-Gawad El-Hofy SECOND EDITION Fundamentals of Machining Processes Conventional and Nonconventional Processes SECOND EDITION Fundamentals of Machining Processes Conventional and Nonconventional Processes Hassan Abdel-Gawad El-Hofy Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2014 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U. Government works Version Date: 20130620 International Standard Book Number-13: 978-1-4665-7703-9 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained.
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Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http://www.com and the CRC Press Web site at http://www.com I dedicate this edition of the book to Omer, Youssef, Zaina, Hassan, and Hana Contents Foreword. xxv List of Symbols. xxvii List of Abbreviations.3 Classification of Machining Processes.1 Machining by Cutting.3 Form and Generation Cutting.2 Machining by Abrasion.3 Machining by Erosion.1 Chemical and Electrochemical Erosion.4 Variables of Machining Processes.5 Machining Process Selection.2 Tool Angles in Orthogonal System of Planes.3 Relationship between the ASA and Orthogonal Systems.4 Effect of Tool Setting.5 Effect of Tool Feed Motion.1 Requirements of Tool Materials.
29 vii viii Contents 2.2 Classification of Tool Materials.1 Ferrous Tool Materials.2 Nonferrous Tool Materials. Mechanics of Orthogonal Cutting.3 Continuous Chip with a Built-Up Edge.6 Rate of Strain.7 Theory of Ernst–Merchant.8 Theory of Lee and Shaffer.4 Heat Generation in Metal Cutting.1 Cutting Tool Temperature.2 Temperature at Shear Plane.3 Factors Affecting the Tool Temperature. Tool Wear, Tool Life, and Economics of Metal Cutting.2 Forms of Tool Wear.3 Impact of Tool Wear.1 Formulation of Tool-Life Equation.2 Criteria for Judging the End of Tool Life.3 Factors Affecting the Tool Life.3 Built-Up Edge Formation.6 Rigidity of the Machine Tool.3 Economics of Metal Cutting.1 Cutting Speed for Minimum Cost.2 Cutting Speed for Minimum Time.3 Cutting Speed for Maximum Profit Rate. Cutting Cylindrical Surfaces.2 Cutting Speed, Feed, and Machining Time.3 Elements of Undeformed Chip.4 Cutting Forces, Power, and Removal Rate.5 Factors Affecting the Turning Forces.1 Factors Related to Tool.2 Factors Related to Workpiece.3 Factors Related to Cutting Conditions.7 Assigning the Cutting Variables.2 Elements of Undeformed Chip.3 Cutting Forces, Torque, and Power.4 Factors Affecting the Drilling Forces.1 Factors Related to the Workpiece.2 Factors Related to the Drill Geometry.3 Factors Related to Drilling Conditions.8 Selection of Drilling Conditions.2 Elements of Undeformed Chip.3 Forces, Torque, and Power in Reaming.5 Selection of the Reamer Diameter.6 Selection of Reaming Conditions.
Cutting Flat Surfaces.2 Shaping and Planing.1 Shaper and Planer Tools.2 Elements of Undeformed Chip.3 Cutting Forces, Power, and Removal Rate.5 Selection of Cutting Variables.1 Plain-Milling Cutters.2 Cutting Speed of Tool and Workpiece Feed.3 Elements of Undeformed Chip.4 Forces and Power in Milling.5 Surface Roughness in Plain Milling.7 Factors Affecting the Cutting Forces.1 Face-Milling Cutters.2 Elements of Undeformed Chip.3 Selection of Milling Conditions.2 Chip Formation in Broaching.3 Broaching Force and Power.5 Accuracy and Surface Finish. High-Speed Machining.2 History of HSM.3 Chip Formation in HSM.4 Characteristics of HSM.6 Advantages of HSM.7 Limitations of HSM. Machining by Abrasion.6 Grinding-Wheel Designation.8 Selection of Grinding Wheels.10 Truing and Dressing.11 Temperature in Grinding.3 Economics of Grinding.1 Elements of Undeformed Chip.2 Cutting Forces, Power, and Removal Rate.3 Factors Affecting the Grinding Forces.6 Surface Grinding Operations.1 Plain (Periphery) and Face Grinding with Reciprocating Feed.2 Surface Grinding with a Rotating Table.3 Creep-Feed Grinding.1 Elements of Undeformed Chip.2 Forces, Power, and Removal Rate.3 Factors Affecting the Grinding Forces.4 Factors Affecting Surface Roughness.6 Cylindrical Grinding Operations.1 External Cylindrical Grinding.2 External Centerless Grinding.3 Internal Cylindrical Grinding.4 Internal Centerless Grinding.5 Wheel Speed and Workpiece Feed. Abrasive Finishing Processes.2 Mechanics of Lapping.1 Kinematics of Superfinishing.
Modern Abrasive Processes.1 Mechanism of Material Removal.3 Factors Affecting Material Removal Rate.2 Abrasive Jet Machining.1 Material Removal Rate.3 Abrasive Water Jet Machining.4 Abrasive Flow Machining.5 Magnetic Field Assisted Finishing Processes.1 Magnetic Abrasive Machining.3 Material Removal Rate and Surface Finish.2 Magnetic Float Polishing.4 Magnetorheological Abrasive Flow Finishing. Machining by Electrochemical Erosion.2 Principles of ECM.3 Advantages and Disadvantages of ECM.4 Material Removal Rate by ECM.8 Economics of ECM. Machining by Thermal Erosion.1 Mechanism of Material Removal.3 Material Removal Rates.5 Heat-Affected Zone.3 Laser Beam Machining.1 Material Removal Mechanism.4 Electron Beam Machining.1 Material Removal Process.5 Ion Beam Machining.6 Plasma Beam Machining.1 Material Removal Rate. Combined Machining Processes.2 Electrochemical-Assisted Processes.5 Ultrasonic-Assisted Electrochemical Machining.3 Thermal-Assisted Processes.1 Electroerosion Dissolution Machining.2 Abrasive Electrodischarge Grinding.3 Abrasive Electrodischarge Machining.4 EDM with Ultrasonic Assistance.5 Electrochemical Discharge Grinding.6 Brush Erosion Dissolution Mechanical Machining.2 Magnetic Abrasive Microfinishing.5 Micro-Ultrasonic Machining.1 Micromachining by Thermal Erosion.2 Micromachining by Electrochemical Erosion.3 Combined Micromachining Processes.1 Chemical-Assisted Mechanical Polishing.3 Electrolytic In-Process Dressing of Grinding Wheels.3 Factors Affecting Machinability.1 Condition of Work Material.2 Physical Properties of Work Materials.4 Machinability of Engineering Materials.1 Machinability of Steels and Alloy Steels.2 Machinability of Cast Irons.3 Machinability of Nonferrous Metals and Alloys.4 Machinability of Nonmetallic Materials.
Machining Process Selection.2 Factors Affecting Process Selection.3 Dimensional and Geometric Features.9 Process and Machine Capability. 503 Foreword I am pleased and proud to introduce this book. It will fill a much-needed niche in machining textbooks for under- and postgraduates, as well as for those in engineering practice. Machining processes account for a large proportion of time and effort in the production of engineered components.
Parts of various sizes, shapes, and, inexorably, of increasing accuracy and complexity are continuously needed to meet the demands of a wide range of industries and users. Conventional methods of mechanical machining to tackle these machining requirements were first established many centuries ago. They have gradu- ally evolved into more sophisticated techniques as related areas of technol- ogy continue to emerge and new materials continue to be developed for tools and as workpieces. With all these developments, the selection of the right machining process for a particular application can be a daunting task.
It is the place of those who teach manufacturing in our universities and colleges to provide a proper education for students on which to base sound decisions on problems they later meet in practice. This book seeks to provide this kind of instruction. The basic principles of machining techniques are explained in four useful introductory chapters. The author then delves more deeply into the subject by introducing the cutting of cylindrical and flat surfaces and the various techniques that may be employed.
High-speed machining occupies a strategic place in many manufacturing companies; this topic is covered in a useful chapter that describes its princi- ples and advantages. Chapters 8 and 9 address basic abrasive machining and finishing. The author follows this with a discussion of modern “nontradi- tional” processes. This leads the reader to consider the other main “nontradi- tional” processes of electrochemical machining (ECM) and electrodischarge machining (EDM) in Chapters 11 and 12, after which the author presents a range of combined hybrid machining methods in Chapter 13.
Consideration is given to the recent interest in micromachining in Chapter 14. Chapter 15 cov- ers issues related to machinability of engineering materials while Chapter 16 presents the main factors affecting the selection of a machining process. I found the use of solved problems and review questions used to test the knowledge and understanding of the reader to be a constructive approach to reinforcing the material covered. Professor Hassan El-Hofy began his research career collaborating with me on hybrid unconventional machining while earning his PhD.
It was an enriching experience for both of us. Since that time, I have been pleased to see the many research papers of international standing that have been pro- duced by him. xvii xviii Foreword This book marks another stage in his professional life: of a journey for him beginning with his first researches to his present station as a senior professor, culminating in transferring his knowledge to a fresh generation of engineers. I trust that they in turn will now benefit from his experience as they study this book.
McGeough, FRSE, FI, Mech E, FIEE The University of Edinburgh Edinburgh, Scotland Preface Machining processes produce finished parts, ready for use or assembly, at high degree of accuracy and surface quality by removing a certain machin- ing allowance from the workpiece material. The removal of material can be achieved by cutting, abrasion, and erosion. Nonconventional machining by erosion of the workpiece material regardless of their mechanical prop- erties has emerged to tackle problems associated with cutting or abrasion processes. Some machining processes are combined together for achieving higher machining rates, greater product accuracy, and the best possible sur- face characteristics.
Many aspects in the field of machining have been covered in detail in the literature, but this book provides a comprehensive coverage of the field in a single book. I am glad to present this new, revised edition, which has benefited from the suggestions and comments received from readers and professors of vari- ous universities. This new edition covers the fundamentals of machining by cutting, abrasion, erosion, and combined processes. It has been expanded and improved and consists of two new chapters that deal with the concept of machinability and the roadmap to selecting a machining process that meets the required design specification.
This new edition is a fundamental textbook for undergraduate students enrolled in production, materials, industrial, mechatronics, marine, and mechanical engineering programs. Additionally, students from other disci- plines may find this book helpful with courses in the area of manufacturing engineering. It will also be useful for students enrolled in graduate programs related to higher-level machining topics. Professional engineers and techni- cians working in the field of production technology will find value here as well.
The treatment of the different subjects has been developed from basic principles, and knowledge of advanced mathematics is not a prerequisite. Along with fundamental theoretical analysis, this book contains machining data, solved examples, and review questions that are useful for students and manufacturing engineers. A solutions manual is supplied with the book to help those adopting the book. The book is divided into 16 chapters.
A brief description of each follows the list: Chapter 1: Machining Processes Chapter 2: Cutting Tools Chapter 3: Mechanics of Orthogonal Cutting Chapter 4: Tool Wear, Tool Life, and Economics of Metal Cutting xix xx Preface Chapter 5: Cutting Cylindrical Surfaces Chapter 6: Cutting Flat Surfaces Chapter 7: High-Speed Machining Chapter 8: Machining by Abrasion Chapter 9: Abrasive Finishing Processes Chapter 10: Modern Abrasive Processes Chapter 11: Machining by Electrochemical Erosion Chapter 12: Machining by Thermal Erosion Chapter 13: Combined Machining Processes Chapter 14: Micromachining Chapter 15: Machinability Chapter 16: Machining Process Selection Chapter 1 introduces the history and progress of machining.