An Instantaneous Rigid Force Model For 3-Axis Ball-End Milling Of Sculptured Surfaces

An instantaneous rigid force model for prediction of cutting forces in ball-end milling of  sculptured surfaces is presented in this paper. A commercially available geometric engine is used to represent the cutting edge, cutter and updated part geometries. The cutter used in this work is an insert type ball-end mill. Intersecting an inclined plane with the cutter ball nose generates the cutting edge. Immersion geometry along the tool path is computed using the contact face between the ball-end mill and the solid model of the updated part. The engaged portion of the cutting edge is divided into small differential oblique cutting edge segments. Friction, shear angles and shear stresses are obtained from orthogonal cutting data available in the open literature. For each tool rotational position, the cutting force components are calculated by summation of the differential cutting forces. The developed model has been verified through experiments performed on several workpieces with different front and side angles. The predicted cutting forces have shown good agreement with experimental results. The developed model can be used as an efficient tool for predicting cutting performance in ball-end milling of sculptured surfaces of dies and moulds.