Planning and implementation of tool path computer controlled polishing optical surfaces

The application of 'small tool' based on computer controlled is a breakthrough in modern optical machining. Dwell time distribution calculated by the iterative convolution algorithm is normally expressed by the points of intersection on the grid; however, the polishing tool path is composed of multi-segment polylines in fact. Therefore, it is required to calculate the time required when the polishing tool moved along the polylines on the workpiece surface before polishing. The algorithm to calculate the dwell time on each polyline of the tool path has been developed, thereby the deterministic material removal on workpiece surface by polishing tool can be achieved. A tool path algorithm based on fractal geometry has been developed, and the points of intersection on the grid are used as the endpoints of polylines directly. Each polyline dwell time is presented by the mean value of dwell time of two endpoints. A group of surface error data is simulated with actual parameters by spiral path and fractal path with the same number nodes. The contrasted results show that most of error results of the fractal path are better than spiral path. The intersection algorithm has been developed to optimize fractal path, thereby the fractal path can be used in polishing workpiece surface with various border efficiently.