Dimensional Tolerance Analysis of Mechanical Assemblies with Symmetric and Asymmetric Tolerances

Abstract

AbstractGeometric and dimensional tolerances are the key factors for the proper assembly of the parts, their manufacturability, and design functions. Hence, these need proper evaluation. This paper presents automatic tolerance analysis of the dimensional tolerances by using modified worst-case and root sum square (statistical) methods. This helps in reducing production and assembly time, error and human interaction, leading to lower manufacturing cost. In contrast to the original worst-case and root sum square methods which consider only symmetric tolerances without sensitivity, the modified methods can handle the asymmetric tolerances and also consider sensitivity. The influences of the lower and upper tolerance bounds of the manufactured dimensions on the assembly lower and upper bounds are shown in the form of percentage contributions on graphs in the modified models. In the modified models, linear and nonlinear problems are defined by using the Taylor series expansion which is implemented in the MATLAB. Finally, a perspective overview for future research of automatic tolerance analysis for the other problems is presented.KeywordsDimensional tolerance analysisWorst-case and statistical methodsLinear and nonlinear variablesSymmetric and asymmetric tolerancesUpper tolerance limit and lower tolerance limitPercentage contribution