Sculpture surface machining

Abstract

ABSTRACT The ball end milling process is used extensively in machining of sculpture surfaces in automobile, die/mold and aerospace industries. In planning machine operations, the process planner has to be conservative in selecting machining conditions with respect to metal removal rate in order to avoid unwanted results such as chipping, cutter breakage or overcut due to excessive cutter deflection. These problems are particularly important for machining of sculptured surfaces where axial and radial depths of cut are abruptly changing. For this reason it will be very critical to provide the process planner with guidance in selecting machining conditions. One solution to this problem is to consider the cutting force in the stage of selecting machining conditions. If the process planner can predict the cutting force for a certain machining condition, it would be very helpful in judging whether the selected condition is appropriate. As a result, a mathematical model is developed in this work for the prediction of cutting force system in ball end milling of sculpture surfaces. The model has the ability to calculate the workpiece/cutter intersection domain automatically for a given cutter path, cutter and workpiece geometries. In addition to predicting the cutting forces, the model also determines the surface topography and scallop height variations along the workpiece surface which can be visualized in solid form. Extensive experiments are performed to validate the theoretical model with measured forces and surface topography outputs. Even for complex part geometries, the mathematical model predictions agree well with experimental measurements. m