Application of the grey system in the planning of the measuring points under the range of the dimensional tolerance of a plane workpiece

The grey system was applied in the planning of a number of measuring points for a plane workpiece with a small volume and a limited surface area. The GM(1,1) models were used to predict and assess the trend of variations in the workpiece plane dimensions. Since the dimension values of the measuring points were based on the values shown in the design drawing, the actual measuring values are shown with the phenomenon of fluctuation. Therefore, two GM(1,1) models were used to predict the maximum and minimum values of dimension fluctuations in order to reflect the fluctuations of the measuring points, and further to establish an algorithm that combines the grey system with the planning of the number of measuring points under the range of the dimensional tolerance of a plane workpiece. The advantage of this algorithm is its capability of predicting the degree of dimension variation of the measuring points for a measuring surface based on a limited number of measuring point values. This provides measuring operators with information early enough to determine the number of measuring points for the next workpiece.