3D surface topography simulation and experiments for ball-end NC milling considering dynamic feedrate

Dynamic change of feedrate is almost inevitable in high speed milling along a curved path due to the drive limits of the machine tools. The surface topography caused by the change of feedrate, which has a significant influence on mechanical prosperities and performances of the machined part, cannot be predicted using the existing methods that only consider constant feedrate. To better understand the surface topography formation process in high speed milling and also to more effectively control the machining parameters, in this paper we present a surface topography model for a ball-end cutter, which takes varying feedrate into full consideration. Our model considers the affecting elements including the surface's local geometry, the cutting edge shape, the path interval, as well as the relative motion of tool-workpiece (especially the changes of the tool orientation and feedrate). 3- and 5-axis ball-end milling experiments, in computer simulation and physical cutting, are performed to validate the developed model. The simulation results exhibit good agreement with that of the actual cutting, thereby showing the potential of the developed model for controlling the surface topography and roughness in real NC ball-end milling.