Chatter free tool orientations in 5-axis ball-end milling

• The characteristic equation of 5-axis ball end milling dynamics is modeled in tool-part engagement coordinates.
• The flexibilities of cutter and workpiece are transformed from measurement coordinates to engagement coordinates.
• Dynamics of 5 axis ball end milling are modeled in engagement coordinate system.
• Chatter free tool orientations are predicted in frequency domain.
• Chatter free tool orientations are found to maximize the material removal rate and improve the surface quality.

Dies, molds and parts with complex free form surfaces are usually machined with ball end mills on 5-axis CNC machining centers. This paper presents automatic adjustment of tool axis orientations to avoid chatter along the tool path. The process mechanics and dynamics of ball end milling are modeled in cutter-workpiece engagement coordinate system. The structural dynamics of tool and workpiece are transformed to cutter-workpiece engagement coordinates by considering the tool path and the kinematics of the machine tool. The stability of the 5-axis ball end milling is modeled at each tool path location, and the chatter free tool axis orientations are searched iteratively using Nyquist criterion while avoiding gouging limits. The tool path, i.e. cutter location (CL) file, is updated to generate chatter free, 5-axis ball end milling of the parts. The proposed algorithm has been experimentally proven in 5-axis ball end milling tests.