Despite the large improvements in the field of high speed machining, manual polishing operations are still necessary to achieve high quality surfaces named mirror for mould and dies or prosthesis parts. This paper deals with the description of a new polishing method performed on a five-axis machine. This method is based on the use of an abrasive discs mounted on a flexible rotating tool describing trochoidal trajectories. Firstly, the influence of each polishing parameter on the surface roughness is highlighted on a conventional polishing machine currently used in material sciences. Based on this knowledge, a specific application concerning the polishing of a stainless medical prosthesis is detailed in order to get a mirror surface roughness which Ra is less than to 50 nm.

International audienceAlthough 5-axis free form surface machining is commonly proposed in CAD/CAM software, several issues still need to be addressed and especially collision avoidance between the tool and the part. Indeed, advanced user skills are often required to define smooth tool axis orientations along the tool path in high speed machining. In the literature, the problem of collision avoidance is mainly treated as an iterative process based on local and global collision tests with a geometrical method. In this paper, an innovative method based on physical modeling is used to generate 5-axis collision-free smooth tool paths. In the proposed approach, the ball-end tool is considered as a rigid body moving in the 3D space on which repulsive forces, deriving from a scalar potential field attached to the check surfaces, and attractive forces are acting. A study of the check surface tessellation is carried out to ensure smooth variations of the tool axis orientation. The proposed algorithm is applied to open pocket parts such as an impeller to emphasize the effectiveness of this method to avoid collision