The Application of Reliability Methods to Tolerancing

Abstract

Techniques which have been developed to estimate failure probability in reliability analysis are here applied to problems associated with the tolerancing of the dimensions of manufactured components. In particular, a procedure is described which permits, for the general nonlinear problem, the deduction of an estimate of the frequency with which a set of components will fail to assemble together to the design specification. The method may also be used at the design stage to adjust the relative size of tolerances on different dimensions and to permit the relaxation of tolerances to the maximum degree commensurate with a required level of assurance of correct assembly. The calculations required are relatively simple and do not require the use of simulation techniques on a large digital computer. The application of the method described is illustrated by means of examples.