Scanning path generation algorithms for automatic polishing of free-form surfaces in convex domains

Polishing tool paths were constructed to evenly cover a 3-D free-form surface defined within a 2-D convex domain to reduce surface roughness and improve efficiency.Unlike conventional methods,the extended scanning path can vary the number of scanning curves through one position according to the normalized length profile of a group of partitioning curves in a specified direction characterized by curves normal to each boundary and by curves starting or terminating within the surface.Boundary recognition algorithms were developed for the stereo lithography model to optimize the scanning direction and to locate the scanning curve end points.The extended scanning method was illustrated using a surface curve construction case,including surface partitioning,point selection and path point connection.The path length and the spacing interval distribution of neighboring scanning curves quantitatively show that the extended scanning path can adapt to surface variations and improve the coverage evenness.