Algebraic Relationship Between Symmetrical and Asymmetrical Capability Indices

Summary: [This abstract is based on the author's abstract.]Capability indices are widely used to assess the quality of a process in which the target is the midpoint of the tolerance interval. However, few investigations have dealt with asymmetrical tolerances, and no full literature treatment or synthesis shows the similarity between these indices and those commonly used. It is shown that the algebraic links between the indices are similar to those that relate the symmetrical indices proposed in the case of asymmetrical tolerances. This algebraic structure permits families of asymmetrical indices to be proposed. The application is demonstrated in a pharmaceutical filling operation.