OPTIMUM ASSEMBLY USING A COMPONENT DIMENSIONING METHOD

Many tolerance allocation methods based primarily on cost optimisation have been developed in recent years. However, the dimensions of the a ssembly parts are usually determined by convenience or design constrai nts other than the requirements of the assembly itself. The dimensions are often determined to give sufficient clearance during assembly wit hout much consideration given to their tolerances. This is usually fol lowed by a tolerance analysis to check for interference. The dimension s are then adjusted to eliminate any interferences. There is no contro l over the size of the clearance of an assembly. This paper presents a new approach of dimensioning the components of an assembly which woul d allow real control over the size of clearance or interference in an assembly. A unique algorithm in conjunction with a relationship matrix is developed to formulate the dimensions in a tolerance chain into a linear equation. This linear equation is then used to develop the tole rance analysis module. The dimensioning module is accomplished using a separate algorithm in conjunction with the linear equation establishe d. The tolerance analysis and the dimensioning modules are subsequentl y tested on a number of examples.