A certification method for the milling process of free-form surfaces usinga test part

It is generally admitted that the manufacturing of free-form surfaces requi res the use of a CAD-CAM system. The toolpath accuracy and dimensional qual ity of the final shape have to be in accordance with the geometrical specif ications. But most of the time, the final parts present deviations from the expected shape. These deviations may be due to either the toolpath calcula tion (CAM system) or the cutting process itself. In this paper, we propose an analysis of the whole milling process to point out the possible sources of errors. These errors generally lead to geometrical deviations and the fi nal part does not meet the required specifications. As the errors can be li nked to geometrical particularities of the shape, we propose a test part as sociated with check means to bring out problems. The milling of this part u sing two different techniques of toolpath generation shows that obviously b oth toolpaths are not error-free, and that errors result from different geo metrical particularities of the part surfaces.