Measurement point prediction of flatness geometric tolerance by using grey theory

The objective of this study is to improve the efficiency in achieving accurate and speedy inspection when coordinate measuring machine (CMM) is used to measure geometric tolerance. The grey prediction in grey theory was applied in developing the algorithm for predicting the number of measuring points required for measuring geometric tolerance in this article. The said algorithm was used to plan the number of measuring points of the next workpiece and to predict the geometric tolerance dimension of the next workpiece. This step provided better foundation for on line inspection to determine the number of measuring points required for measurement inspection of the next workpiece. Besides, it can predict whether the geometric tolerance of the next workpiece conform with the geometric tolerance dimension marked on the design drawing. This algorithm is used to determine whether the manufacturing process requires modification, in an attempt to save human and material resources and improve failure rate. s paper, the said algorithm refers to the flatness measurement point algorithm in a plane of the workpiece. In planning for the increase of measuring points, this algorithm is bound by the principle of keeping the measurement scope a rectangular shape by adding a row of measuring points. When the prediction value exceeds the designation dimensions range, immediate inspection of the manufacturing process is needed. The concept of on line inspection of the addition of measuring points is also incorporated together with the grey prediction model and concept of standard deviation model in an effort to develop the said algorithm. mental data were also introduced to verify the flatness geometric tolerance measuring points algorithm for the flatness geometric tolerance in a workpiece plane. The objective is to reach a balance between the smallest number of measuring points possible required for inspection and inspection accuracy. Consequently, one can avoid using too many measuring points, which increases the inspection time, while achieving the required measurement accuracy.