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LATEST TRENDS IN MACHINING

PREFACE

It all started sometime in September 1961, when I joined Hindustan Motors Ltd., then the premier automobile company of the country, as a fresh mechanical engineering graduate from Indian Institute of Technology, Kharagpur. Right on the first day of my training, I had to work on a turret lathe for almost the whole of the shift, as the man concerned went to attend to his ailing father without taking an official leave. Today, I feel like thanking him again and again, but I do not know his whereabouts. I don't know if he is alive, as he was quite aged at that time itself. The trade became alluring, as I was learning every day something new. HM was investing significantly in new manufacturing facilities at that point of time. New machine tools with much high production capability were getting installed. Production was increasing. As one of the important assignment, I was involved in the switch over to indexable insert replacing the brazed tools that were in use those days. During my years in machining areas of mechanical division, I improved almost every operation that I worked on. I was responsible for producing the diesel engines of the famous ambassador cars sometime in 1970s with almost no additional capital investment. The same manufacturing lines are producing those diesel engines even today with just few additions. In 1963 itself, I gave a presentation `Reduce delays on setup change over' to `The Institute of Production Engineers' in Calcutta without knowing about the pioneer work on the same subject being done by Shiengo with Toyota in Japan. While working in machining areas in different positions, I kept myself updated with the contemporary technology in machining and wrote a number of articles in different magazines in 60's and 70's. Those were the real busy days with 1620 hours in factory almost every day of the week. I used to educate all the technocrats who worked for me with troubleshooting tips, that all got published in the book- "Troubleshooting Handbook-machining" by Tata-McGraw Hill, New Delhi in 1986. Thereafter, I authored "A Treatise on Gear Manufacturing" and than "Trends in Automobile Manufacturing" for engineers in industry, that were appreciated by almost everyone.

I would, with humility, admit that writing a book could never really be a solo effort just like most things in life. Before I dwell on the people whose contributions were invaluable in the making of this book, I would like to digress for a while to tell the readers my way of reaching at the latest in manufacturing techniques. As the head of production and manufacturing engineering, and

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again that of corporate project planning, I used to meet many experts from different machine tools and equipment manufacturing companies. Immediately after our business talk would get over, I would invariably end up asking these experts about the latest developments and future trends in their respective areas of interest. I have always believed and still feel that such informal confabulation is a wonderful way to get to know the pulse of technological advancements in any area. Besides, I actively participated in academic activities of the Production Engineering Department of Indian Institute of Technology (IIT), Kharagpur, and Jadavpur University, Calcutta. When Shri Rakesh, my eldest son and an alumnus of IIT, Kharagpur joined Industrial Engineering Department at Purdue University, he became an invaluable source for getting more information. Many friends in industry abroad also helped me. I learnt the most from my visits to European countries and Japan where I went quite often for discussion on the manufacturing planning with the collaborators. I also visited a large number of machine tool manufacturers in these countries and interacted with their highest executives, who invariably happened to be qualified technical persons. Most of the top executives in Japanese automobile companies with whom I interacted were very successful manufacturing engineers. I was really fortunate to have been entrusted with the responsibility of General Manager- Technical Services and again as General Manager-Corporate Project Planning of Hindustan Motors where I got a lot of opportunity to get to know the various aspects of manufacturing technology in a much better way. In last few years, I also visited automobile plants in Taiwan (ROC), South Korea, Indonesia, Philippine, and Malaysia, and came to know about appropriate application of high technology in low-tomedium volume production.

Manufacturing technology and management techniques, more so the machining concepts have undergone a sea change in last four decades. This book is an attempt to present to the practicing engineers, managers, and research scholars in engineering industry and institutions the latest trends in machining and a glimpse of the future of machining.

When I started at HM, the transfer machines were the most advanced technology for high volume production. In 1965, I saw the first generation of NC machine working at Vauxhall Motors (UK), which was at that time one of the largest truck manufacturers of Europe. Over the years, the machining centers have evolved from the conventional to special ones and then to the high speed ones. Prismatic components that were produced en masse through flexible setups are now switching to agile and re-configurable facilities. Machining centers are becoming a manufacturing engineer's choice for production volumes up to 3,00,000 per year. Today, it is possible to complete machining of an engine cylinder block or an air-conditioner compressor

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housing on one single machine. Similar is the case with turning centers. Some are becoming very versatile to add all capability of machining centers besides machining processes relating to rotational axis.

To give some more examples, in 60's crankshafts once forged were turned with form tools on multi-slide, multi-tool lathes. Over the years, the same was done using external milling, which was, again, replaced by internal milling and also by turn broaching or turn/turn broaching. In next move, it is the green grinding that is being used for the same purpose. In every area, all the developments were carried out with close cooperation between the users and machinery and equipment builders. The same was true in cutting tools also. Carbide tools replaced most of the HSS tools in machining processes. Throwaway inserts replaced brazed carbide tools. Ceramic tools are also coming up fast to replace carbides in many applications. Coatings have brought a revolutionary improvement in performance of cutting tools. Nanocoatings and diamond coating of carbide have provided new dimensions in machining productivity. There are similar stories in every area of manufacturing. I was fortunate enough to keep a track on the trends. The search for knowing machining as practiced that started sometime in 1961 is very much alive. This book is the result of the same. The trends are changing very fast. With my growing age, perhaps very soon it may not be possible to keep pace with advancements in manufacturing technology. But I am not going to give up so easily. My sons- Rakesh, Rajesh, Anand and my daughter Alpana, and then my grandson Keshav Raman who all are in USA will provide me enough water always till the last day to quench my thirst of the subject. We are trying to create a Website ( manufacturingtrends,com) on the subject very soon, and I promise to keep this updated regularly for those who will be interested.

How can I forget to mention some of the people who have gone on inspiring me to complete this book? My wife, Shrimati Yamuna Sharma has been and will always be the first in my list. In the last 46 years that we have been together, she has almost always managed to significantly contribute in her own sweet way in every endeavor that I undertook.

Some friends such as Shri Deshbir Singh, Managing Director of Harig Crankshafts Ltd. helped me in taking this work more seriously. Mrs. Manju Deshbir Singh, Managing Director of Harig India, Mr. S.N.Misra- President and CEO of BFW, Mr. Y.H.Tata, Managing Director of Machine Tools (India) provided the encouragement to go-ahead. Col.(Retired) Jagjit Singh and his wife, Mr. Nilmani Sinha, and Mr. Vijay Sood have gone through the manuscript and have provided a real help in making it useful. I am really obliged to all and

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many others whose names are not mentioned here but without them I could not have done it. I sincerely hope that this volume will provide my friends in the industry with all the information in one place. The book shall also be providing a direction to researchers in national institutes to work on subjects of real importance to manufacturing industry. However, I would sincerely appreciate if the readers would fill me in on their opinion about this book, so that I can improve it in my next updating. I only hope that you would find it useful. I. R. Sharma A-54, Sector-41, NOIDA 201303 Phone: 4570126, 4571554 E-mail: irsharma@ 1.1.2001

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LATEST TRENDS IN MACHINING

CONTENTS

Sections PREFACE CONTENTS ILLUSTRATIONS ABBREVIATIONS SECTION 1: MACHINE TOOLS- History

Early machine tools, Machine tools of pre-auto era, Grinding wheels and universal grinding machines, Gear manufacturing machines, Cutting tool materials, Evolution of new machine tools, Numerical control and computerized machining.

SECTION 2: MACHINING ? LATEST TRENDS

Quality characteristics of machined surfaces, General trends in machining, Emerging work materials, Machine tools-turning centers, machining centers, flexible manufacturing, agile manufacturing, Feature of advanced machine tools- main drive motors, machine spindle, ways and slide drive, Modular design concept, CNC system, Tool wear monitoring, Accuracy of machine tools, Trends in coolant application and management, Modular work holding systems, Automation.

SECTION 3: CUTTING TOOLS

Tool materials, Top form geometry, Hole making tools, Thread making tools and techniques, Coatings for better tool performance, Tool holding system, Tool clamping systems, Modular/ `quick change' toolings.

SECTION 4: NEW MACHINING CONCEPTS

High speed machining, Hard machining (turning), Dry machining, Near-dry machining, Near?net-shape machining. Machining difficult-to-machine materials, `Bulk' machining.

SECTION 4: ABRASIVE MACHINING/GRINDING

Process, external cylindrical grinding, high speed grinding, creep feed grinding, high efficiency deep grinding, internal grinding, New grinding machines, Grinding wheels, New aluminum oxide abrasive wheels, CBN wheels, Single point OD grinding.

SECTION 5: MACHINING- THE FUTURE

Hexapods, near net shape, new work materials, machine tools, tool materials and coatings, non-traditional machining techniques, machine controls

ANNEXURE-A: MACHINING OF ENGINE COMPONENTS5Cs

C-1 Cylinder Block, C-2 Cylinder Head, C-3 Crankshaft, C-4 Camshaft, C-5 Connecting Rod

ANNEXURE-B: TIPS, CHECKLISTS, AND TROUBLESHOOTING

General, Cutting tools, Drilling, Tapping, Milling, Turning, Grinding

Page number I V

VI IX

2

11

57

101

127

144 151

179

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ILLUSTRATIONS

SECTION 1 1.1 John Wilkenson's cylinder bore mill 1.2 An early lathe 1.3 J. R. Brown' first universal milling machine, 1862 1.4 A machine shop as it looked in1890. 1.5 Charles H. Norton's cylindrical grinder, 1900 1.6 Fellows' gear shaping machine, 1897

SECTION 2 2.1 Deviations in basic workpieces with design change 2.2 Time cycle reduction over years 2.3 Narrowing tolerance over last decades 2.4 Conventional horizontal front loading chucker 2.5 Co-axial horizontal turning centers and sub-spindle turning machines 2.6 An inverted vertical CNC turning chucker 2.7 A unique combination of inverted and conventional spindle orientation 2.8 A 4-axis CNC lathe with twin turret 2.9 A center drive CNC lathe for simultaneous machining at both ends 2.10 Time analysis of two kinds of machining :single spindle and ten-spindle head 2.11 A transfer line with CNC machining center modules 2.12 Agile rotary-index machining setup 2.13 Integral spindle motor design 2.14 Conventional spindle drive VS. integral spindle motor 2.15 A water-cooled spindle housing 2.16 An advance linear way design with roller bearings 2.17 Advance ball screw and roller screw 2.18 A Linear motor drive vs. a ballscrew drive 2.19 Modular concept in machine tool design 2.20 Various inaccuracies requiring regular monitoring 2.21 Tomb stone for vertical machining center 2.22 A typical quick-change fixture 2.23 Gantry load/unload system for a machining line

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