Visual scanning for off-line automatic tool path generation for shear spinning

Use of visual scanning to automatically generate an accurate tool path is presented. Emphasis is on combining low resolution vision with visual control of a precision machine tool to attain the accuracy required for shear spinning. A simplified edge detection method is used to obtain the required sub-pixel accuracy of the mandrel profile. Two different tool paths are generated using two different methods. First, a part program is generated assuming all data points extracted during scanning are joined by straight lines. Second, assuming that all segments of the mandrel profile consists of circular sections and straight line segments, a curvature detection algorithm is used to identify segments. Then the segments are put together in a part program. Dimensional accuracy of components spun using these two methods are compared with the actual profile. While both methods gave acceptable results, the segment extracted tool path produced a component with superior dimensional accuracy.