Improving productivity and part quality in milling of titanium based impellers by chatter suppression and force control

Large axial depth of cuts used in the flank milling of gas turbine impellers result in severe chatter vibrations and high cutting forces. Variable pitch cutters can be used to suppress chatter in milling of these extremely flexible components. A novel design method for variable pitch cutters is presented. Cutting forces in 5-axis milling cycles continuously vary due to changes in tool orientation and depth of cut. Adaptive force control or milling force models can be used to keep the forces at a constant level which reduces cycle times significantly. Benefits of both approaches are demonstrated through examples.