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.