From the Publisher
From the Inside Flap
Have you ever wondered: "How did they make that? Why did they make it in such a poor way?" Choosing a manufacturing method is part of the design process for nearly everything that is made. Today, that is a complicated choice, but an essential one.
Humans have been making useful objects ever since they discovered that they could hold tools. Until about two hundred years ago, most objects were manufactured by handin fact, the word "manufacturing" literally translated from Latin means "to make by hand." By today's standards, these objects were crudely made. Parts were not interchangeable. Each part was individually fitted to the others so that the total mechanism worked, at least until something broke. Then, the replacement part had to be made specially to fit.
Today's society could not exist without modern manufacturing and production techniques. In fact, one of the indicators used to measure a country's economic strength is its manufacturing and production capability. Mass production with interchangeable parts is vital to our standard of living. One cannot even imagine the difficulty involved in making an automobile, a modern tractor used on a farm, or a commercial aircraft if all the parts had to be made by hand. Without modern manufacturing methods, we could not even feed the present population.
The Industrial Revolution brought about two radical changes: the standardization of measurements and the development of manufacturing techniques that allowed interchangeable parts to be mass produced. Before then, workers measured lengths by cubits, hands, or other imprecise gauges. When measurements became standardized, an inch was an inch or a millimetre was the same no matter whose scale was used.
A result of standardization of measurements was the development of interchangeable parts. Using standardized measurements, workers could make parts that would fit similar mechanisms.
With the advent of the steam engine and the resulting portable power source, workers had power available that could run machine tools, make machine tools handle large capacities not possible with human or animal power, and increase production. Workers could make dozens of the same parts at a time and produce them more cheaply than ever before.
The immediate result was that manufactured goods became cheaper, more people could own those goods, and the standard of living rose.
Modern manufacturing is changing continuously. Standards that were adequate a decade ago are not good enough to make the state-of-the-art machines operate properly. Methods of manufacturing will always improve and new materials will change the way that we make things.
Look around. How many products can you list that have become obsolete in your lifetime? We have gone from the vacuum tube to the transistor to the integrated circuit even before some of the old vacuum tubes have burned out. In cameras, we have progressed from black-and-white film to color film to instant prints to filmless electronic-imaging cameras in less than half a lifetime. Thirty years ago, classroom exams were mimeographed, or simply written on the chalkboard. Now, photocopier machines are the standard. As late as 1975, engineers used slide rules, which now are as obsolete as the abacus. Electric typewriters hailed as state of the art are antiques compared to the modern computer and word processing systems. This latter invention is one for which the authors of this text are truly grateful.
This text is as up-to-date as the authors could make it, yet even the newest manufacturing techniques described in this text might be replaced before you finish this course. Please consider this text only a starting point. It is the responsibility of each engineer and technician to keep current with new technologies in his/her field! Professionals should read technical journals and trade magazines in their field and join technical societies. These societies publish magazines and books and offer workshops to keep their members current. The era when a person could learn a skill and be set for life ended long ago. One must keep up-to-date!
Societies, as well as individuals, must keep up with change. The United States is the only major industrial country that does not use the metric system exclusively. Eventually, the United States and American industry will have to join the rest of the world in this standardization of measurement. Therefore, at the request of many industries, we have included some metric system examples and problems in this book. This is a good time to master the metric system if you have not already done so. You are going to need it.
Now, the authors would like to take the liberty of passing on to the students a few words of advice, which they have learned from being students themselves for many years. Learning is not a "passive" experience. You cannot learn anything simply by watching someone else do it. You cannot learn to play the piano by watching a concert pianist perform nor learn to play baseball by simply being in the bleachers watching the game. You have to do it yourself to learn it. Neither can you learn to solve a problem by watching your instructor work the problem on the board. You have learned a new concept when you, by yourself, can use it properly. Even after watching your instructor solve a problem, copy it, take it home, and rework the problem yourself. When you can make it look easy and can even explain it, then you will be a "pro" at it. Remember, your instructors have been working these problems for several years to get to the point where they can teach it and make it look easy.
Learn to take notes in class. You would be surprised by how much you forget between classes. It is also helpful to review the notes immediately each day. Further, the notes provide a good review in preparation for tests.
The format for this text is as follows: A concept is introduced, discussed, and followed immediately by questions and exercises. Get in the habit of answering the questions and working the exercises as you come to them. They have been designed to help you master a block of material before building on it with new concepts. Don't wait until test time to do the work, or the course will get ahead of you.
Above all, stick with it! It takes hard work to master these new concepts and organize all of this material, but you need them in order to be ready to take your place in today's industry.
Good luck in the course. ACKNOWLEDGMENTS
We would like to express our appreciation to the reviewers of this book: Ergun A. Oguz, Gwinnett Technical Institute, GA; Thomas Reyman, Mesa Community College, AZ; Dr. Morteza Sadat-Hossieny, Marshall University, WV; Musasa E. Ssemakula, Wayne State University, MI; and Neil K. Thomas, Ivy Tech State College, IN.
William O. Fellers
William W. Hunt --This text refers to an out of print or unavailable edition of this title.