This article deals with the analysis of the part positioning in models of
mechanical assemblies and its systematic recording. This analysis is essential in
the process of obtaining the functional dimensioning of each component that
meets the geometric requirements set by the specifications.
The method is derived from knowledge of the nominal models of each component
and the whole assembly. The first phase of functional dimensioning is based
on the analysis of the positioning of each part in any possible operating state. The
part positioning depends on the identification and definition of the contact surfaces
and their order of preponderance. This method makes it possible to obtain
the dimensioning of the contact surfaces by means of position specifications. In
addition, by precisely defining the part positioning, the ISO dimensioning can be
carried out in such a way that the consistency of the dimensioning with the requirements
can be easily verified.
Every functional requirement will generate a tolerance stackup of influencing dimensions
that must be recorded. Considering that an assembly or device may
have several operating states, parts may have several operating positions which
shall be analyzed and provide different dimension tolerance stackups and functional
dimensions.
For the above reasons, the method must use the language common to all these
environments, which is none other than the ISO-GPS language.
