Dimensional Errors in Longitudinal Turning Based on the Unified-Generalized Mechanics of Cutting approach. Part II: Machining Process Analysis and Dimensional Error Estimate

The model presented in the first part of this work is used here to estimate the diameter error in the most common turning operations. In fact, the diameter error is considered as a variable depending on the deflections of the tool, workpiece holder and workpiece, which are considered the main factors responsible for the machining accuracy. The proposed model has been applied to the three most common turning schemes related to workpiece fixturing, where the workpiece is clamped in a chuck, or supported between two centers, or clamped in a chuck at the spindle and supported on a center at the tailstock. Some numerical examples have been computed using the proposed model to predict the diameter error along the workpiece and the cutting force along the workpiece axis, as well as the influence of the cutting force components on the error prediction. The results provide additional insight into error formation in the turning process. Finally, some experimental tests have been carried out in order to validate the developed model. Good agreement has been obtained between numerical and experimental results. The proposed model represents a first step towards accuracy control in machining operations and, thus, towards optimization of the manufacturing process.