Optimal selection of machining direction for three-axis milling of sculptured parts

In the field of free form surface machining, CAM software allows one to manage various modes of tool-path generation (zig-zag, spiral, z-level, parallel plan, iso-planar, etc.) leaning on the geometry of the surface to be machined. Various machining strategies can be used for the same shape. Nevertheless the choice of a machining strategy remains an expert field. Indeed there are no precise rules to facilitate the necessary parameter choice for tool-path computation from the analysis of the numerical model of a part and the quality requirements. The objective of this paper is to provide a method to assist in the choice of the machining direction for parallel plane milling of sculptured parts. The influence of the tool-path on the final quality according to the intrinsic geometrical characteristics of the latter (curves, orientation) was studied. The directional beams are introduced and defined from the local surface parameter. Finally a methodology to optimize machining time while guaranteeing a high level of quality was developed and applied to examples .