Generating optimal multi-segment cutting patterns for circular blanks in the manufacturing of electric motors

The author presents a method to generate optimal multi-segment cutting patterns to improve the material usage of the circular blanks in the manufacturing of rotors and stators of electric motors. In the patterns generated, the sheet is divided into segments with cut lines perpendicular to the sheet length. The width of the segments equals to the sheet width. The lengths of the segments may be different. A segment includes one or more strips that are parallel to the sheet length. More than one row of identical blanks can appear in a strip. The method applies the property of the optimal patterns to reduce the number of segment lengths that should be considered. It uses the knapsack algorithm to determine the optimal arrangement of blanks on each segment and the numbers of the segment lengths in the sheet to make the material usage reach its maximum. The computational results indicate that the method is efficient both in computation time and in material usage. The solution to an example is given.