chapter  4
21 Pages

The Contact Between Rough Surfaces

All surfaces, natural or manufactured, are not perfectly smooth. The smoothest surface in natural bodies is that of the mica cleavage. The mica cleavage has a roughness of approximately 0.08 µin. The roughness of manufactured surfaces varies from a few microinches to 1000 µin. Roughness represents the deviation from a nominal surface and is a composite of waviness and asperities. Surface roughness plays an important role in machine design. During the metal cutting operation, a machined surface is created as a result of the movement of the tool edge relative to the workpiece. The quality of the surface is a factor of great importance in the evaluation of machine tool productivity. A generalized computer-based model is developed for predicting surface roughness for any given condition which takes into consideration all the important parameters influencing the deterministic vibratory behavior of the machine tool-workpiece system.