Dynamic Force Model for 3- Axis Ball-End Milling of Sculptured Surfaces

Dynamic force model is used to estimate cutting forces of sculptured surface considering dynamic characteristics. Two programs were used for calculations, “ACIS” the 3-D geometric modeler and “VISUAL BASIC”. Two programs were edited and used to preform the calculations, the scheme program to model the work piece ,tool and cutting edge and to obtain the geometric data and the VISUAL BASIC program designe to use ACIS geometric data to calculate the cutting forces. The engaged part of the cutting edge and work piece is divided into small differential oblique cutting edge segments. Friction, shear angles and shear stresses are identified from orthogonal cutting data base available in literature. The cutting force components, for each tool rotational position, are calculated by summing up the differential cutting forces. The machine tool was modeled by a two degree of freedom mass, spring and damper vibration system. Laboratory tests were conducted to verify the pridictions of the model. The work pieces were prepared from CK45 steel using an insert type ball-end cutter. No coolant was used in any of the experimental works. The cutting forces predicted have shown good agreement with experimental results.