Normalization of reproducibility and suitability indexes for assessment of products or production services quality

Abstract

A technique is proposed for estimating the probability of the possible appearance of defective products (or the inconsistency of the production service) on the basis of the suitability and reproducibility indexes of the production process. The index of reproduction is recommended to be calculated on the basis of the standard deviation, which can be established by the average span of the control map and the limits of the tolerance field. At the same time, the production process must necessarily be in a state of statistical controllability. The suitability index can not be calculated on the basis of the control card characteristics, but is calculated solely on the basis of the total of the standard deviation, which is calculated on the basis of the Bessel formula and tolerance limits. The production process does not need to be statistically controllable. Conclusions on the suitability or insufficiency of the products (production services) are based on the value of the indexes of reproduction and suitability, which can take values less than or greater than one. On the basis of the obtained values of these indexes, the probability of production appearance or characteristics of the production process, that does not match the established requirements, is established.