Surface Topography and Roughness Simulations for 5-Axis Ball-End Milling

In five-axis high speed milling of freeform surface with ball-end cutters, unwanted machining results are usually introduced by some error effects. Hence precise modeling and simulation of milled sculptured surfaces topography and roughness is the key to obtain optimal process parameters, satisfactory surface quality and high machining efficiency. In this paper, a predictive model for sculptured surface topography and roughness of ball-end milling is developed. Firstly, a mathematical model including both the relative motion of the cutter-workpiece couple and some influential factors on machined surface quality such as the tool runout, tool deflection and tool wear is proposed, and subsequently the analytical form of the tool swept envelope is derived by means of homogeneous coordinate transformation. Then the minimal z-values of the corresponding points lied in discrete cutting edges model and Z-map workpiece model are used to update the workpiece surface topography and to calculate 3D surface roughness. Finally, the simulation algorithm is realized with Matlab software. A series of machining tests on 3Cr2MoNi steel are conducted to validate the model, and the machined surface topography is found in good accordance with the simulation result.