Metal Shaping Processes. Vukota Boljanovic
and potentialities of these processes and their competitive aspects. The text, as well as the numerous formulas and illustrations in each chapter, clearly shows that shaping processes, as a part of manufacturing engineering, constitute a complex and interdisciplinary subject. The topics are organized and presented in such a manner that they motivate and challenge students to develop technically and economically viable solutions to a wide variety of questions and problems, including product design.
The field of mechanical engineering and manufacturing technology continues to advance rapidly, transcending disciplines and driving economic growth. This challenging field continues to incorporate new concepts at an increasing rate, making manufacturing a dynamic and exciting field of study. In preparing this book my most important goal was to provide a comprehensive state-of-the-art textbook on the most common metal shaping processes; an equally important aim was to motivate and challenge students to understand and later, perhaps, to work with this common manufacturing process.
The book is organized into four parts with thirteen chapters. The first part of the book covers casting, molding, and other processes in which the starting material is a heated liquid. The discussion is divided into three chapters: The fundamentals of metal casting processes, metal casting processes, and metal casting design and materials.
The second part of the book deals with basic particulate processing, these in which the starting materials are metal powders. The powder metallurgy of the various metals is discussed as one unit.
The third part discusses the most commonly used metal deformation processes, in which the starting materials are solid. This section is divided into five chapters: The fundamentals of metal forming, rolling, forging, extrusion and drawing, and sheet metal working.
The fourth part of the book discusses the most commonly used metal removal processes, those in which the starting materials are likewise solid. This part of the book is divided into four chapters: The fundamentals of metal machining, machining processes, abrasive machining processes, and nontraditional machining processes.
Although the book provides many calculations, illustrations, and tables, it should be evident that detailed analytical mathematical transformations are not included; however, the final formulas derived from them (which are necessary in practical applications) are included.
Measurements are given in both ISO and U.S. unit systems. At the end of each chapter, review questions are given that allow students to review chapter contents in a quick and enjoyable fashion.
By reading and studying this book, my hope is that students will be introduced to an academic subject that is as exciting, challenging, and as important as any other engineering and technology discipline; professionals will also find this book a very effective tool and reference.
The author owes much to many people. I am grateful to my son Sasha, who labored countless hours at converting AutoCAD drawings into a format compatible with commercial printing. In addition, I would like to acknowledge John F. Carleo, editorial director at Industrial Press, who worked with me during the manuscript preparation and persuaded me of the continuing interest of Industrial Press in publishing my fourth book. Finally, I wish to thank Em Turner Chitty for her help.
Vukota Boljanovic
Knoxville, Tennessee
Classification Of Shaping Processes
Production Equipment And Tooling
Manufacturing is the procedure by which materials are transformed into desired shapes. Materials are first formed into preliminary shapes, and then refined into more precise shapes, after which the final shaping and finishing operations are performed. The shaping process is one broad category of manufacturing processes. In the shaping process, a component or product can be created from a solid, granular, particle state, or liquid state, meaning the state of the work material in the shaping phase. In the design of a shaping process, the only factors that are known at the outset are the final product shape and the material with which it is to be made. It is the engineer who must design a process to make a defect-free product; the engineer always operates under constraints due to the shape of the desired object, the material’s properties, the cost of production, the time available, and many other factors. Shaping processes influence the vast majority of products bought or used by consumers. This is the reason why in this book so much space will be devoted to discussing particular shaping processes. These are processes that you, as a designer or manufacturing engineer, will most likely use or encounter while engaged in the practice of mechanical or industrial engineering.
CLASSIFICATION OF SHAPING PROCESSES
Classification of technological shaping processes may be based on many different criteria, depending on the purpose of the processes. In general, shaping process can be classified into two main categories: primary and secondary shaping processes. The primary shaping processes form the overall shape of the product or the component that will, with other parts make up the final product’s shape. The purpose of secondary processes is to provide the final, precisely shaped surfaces that will meet product requirements, such as surface or dimensional tolerances.
The classification used in this book refers to primary shaping processes and is based on the state of the starting material. There are four broad categories of primary shaping processes for metals (Fig. I.1):
Fig. I.1 Classification of primary metal shaping processes.
1.Casting, molding, and other processes, in which the starting material is in the form of a heated liquid.
2.Particulate processing (powder metallurgy), in which the starting material is a powder.
3.Deformation processes, in which the starting material is a solid that is deformed to shape the components.
4.Metal removal processes, in which the starting material is a solid whose size is sufficiently large for the final geometry of parts to be circumscribed by it; in these processes, the unwanted material is removed as chips, particles, and so on.
Casting and molding. In this category starting material is heated to transform it into a liquid state; after that, the material is poured or in some other way forced to flow into a die cavity and allowed there to solidify, thus taking the shape of the cavity, which is nearly the shape, or the “net” shape, of the part. This type of primary shaping process is called casting. Casting processes use two types of mold: expandable mold (sand casting, shell mold casting, investment casting, and ceramic mold casting); and permanent mold (permanent-mold casting, die casting, centrifugal casting, and squeeze casting).
Particulate processing. In this category the starting materials are metals or ceramics in powder form. In this process, metal powders are compressed into desired shapes (often complex) and sintered (heated without melting) to form a solid component. This type of primary shaping process is called powder metallurgy.
Deformation processes. In this category the starting material is in a solid state. The initial shaping of the workpiece is accomplished through the application of external forces to the solid work material, with these forces being in equilibrium. Wit the application of load to the workpiece, internal stress and displacements are generated, causing shape distortions. This type of shaping process is called “deformation”.
Deformation