Tolerance Analysis

So far, we have discussed the tolerancing concepts and how tolerances are represented. We have also seen that tolerance assignments to several components of an assembly might meet its functional requirements and should reduce manufacturing cost. With all tolerances assigned to the several components (parts) of an assembly, the designer should check that the combined influence or accumulation of all of these tolerances (tolerance stackup) does not cause an inoperable or malfunctioning assembly. Analysis of tolerances and their stackup is significant because tolerance assignments are generally done on a part-by-part basis.

Therefore, tolerance analysis is defined as the process of checking the tolerances to verify that all of the design constraints are met. Tolerance analysis is sometimes known as design assurance.

Tolerance analysis needs two steps (assuming tolerances have already been assigned). First, all dimensions that affect the analysis must be identified. Since dimensions in one direction are frequently related, find out the relations among them. When the extraction of the tolerance information is complete, the second step is to use it to section. These methods might be implemented into some tolerance analysis so that to make an automatic tolerance analysis. Manual methods for tolerance analysis are time-consuming and error-prone. For complicated problems, usually they are infeasible.

The objective of tolerance analysis is to find out the variability of any quantity that is a function of product dimensions. Most frequently, these quantities are also dimensions, and are called design functions. Product dimensions & variables that control the behaviour of a design function are called as design function variables. The variability of the design functions is utilized to assess the suitability of a specific tolerance specification.