Target selection for an indirectly measurable quality characteristic in unbalanced tolerance design

摘要

A quality characteristic that cannot be measured directly during a production process should be measured or controlled by another measurable variable. The immeasurable quality characteristic is a junction of the directly measurable variable. For this type of quality characteristic, if the tolerance design is unbalanced, or if the relationship between the measurable variable and immeasurable quality characteristic is nonlinear; setting the process mean at the target value of the measurable variable will not minimise the expected quality loss. In this paper, the optimal process mean of the measurable variable is determined such that the expected quality loss is minimised for the above conditions. The results are compared with those of a directly measurable variable.