SECTION 2.2
The Mechanics of Chip Formation

Empirical metal-cutting studies reveal several important characteristics of the chips formed during the broaching process: (1) the cutting process generates heat, (2) the thickness of the chip is usually greater than the thickness of the layer from which it came, (3) the hardness of the chip is usually much greater than the hardness of the parent material, and (4) the other three relative values are all affected by changes in cutting conditions and in properties of the material to be machined (see Figure 2-1). These observations also indicate that the process of chip formation is one of deformation or plastic flow of the material, with the degree of deformation dictating the type of chip that will be produced