As discussed in the Preface, the geometry of cutting tools affects the quality and
productivity of machining operations, chip control, magnitude, and direction of the
cutting force and its components. Although these correlations are known
phenomenologically, i.e., from the testing and implementation practice of various
tools, little is known about their physical nature. Unfortunately, these experiencebased
facts are often incomplete and contradictiing as they are normally considered ignoring system properties of the cutting system. As a result, they cannot provide
much guidance in tool design in terms of selection of the optimal for a given
application, tool geometry. The theory of metal cutting as taught in student’s texts
is of little help as it does not consider correlations between essential parameters of
the cutting tool geometry and the physics of this process. Only when the physics of
the metal cutting process is understood and the system properties of the metal
cutting system are accounted for, can the proper tool geometry be selected. This,
however, can happen if the proper answer a simple question: What is metal
cutting? is known so one can answer the following questions:
1. What is the difference between metal cutting and cutting?
2. If a polymer or any other non-metal (wood, stone) material is cut by means
of turning, milling, drilling, etc., what should this process be called?
3. What kind of cutting is performed by a knife or by a pair of scissors?
This chapter aims to provide the answers to these questions. These answers should
help to distinguish metal cutting from other closely related manufacturing
operations, revealing its unique physical features controlling this process. As a
result, the essence of the metal cutting process can be understood so the parameters
of the cutting tool geometry can then be selected to optimize this process.