Engineering Tolerance - An Alternative View of Tolerances

An Alternative View of Tolerances

Genichi Taguchi and others have suggested that traditional two-sided tolerancing is analogous to "goal posts" in a football game: It implies that all data within those tolerances are equally acceptable. The alternative is that the best product has a measurement which is precisely on target. There is an increasing loss which is a function of the deviation or variability from the target value of any design parameter. The greater the deviation from target, the greater is the loss. This is described as the Taguchi loss function or "quality loss function", and it is the key principle of an alternative system called "inertial tolerancing".

Research and development work conducted by M. Pillet and colleagues at the Savoy University has resulted in industry-specific adoption. Recently, the publishing of the French standard NFX 04-008 has allowed further consideration by the manufacturing community.