Tolerance Analysis with eM-TolMate

This article presents a review of a commercial computer-aided tolerance analysis tool, eM-TolMate, which is embedded in four major CAD systems (Catia [1], UG [2], Pro/E [3], SDRC [4]). eM-TolMate combines the Monte Carlo statistical simulation techniques with an internal tolerance management system and identifies the key characteristics (i.e. dimensions/clearances of interest) of nominal component models that are critical to proper assembly. Features and tolerances are directly created in CAD models and both single component or multi component analyses are available. For assemblies, eM-TolMate offers the capability to apply user-defined assembling rules or to automatically detect mating conditions. Actual features are varied within the specified tolerance range, and standard or user-defined statistical distributions are used in simulation runs to determine variations of key characteristics. It also offers the capability to rank tolerances based on contribution to the variation, so the user can identify where tolerances need to be tightened or can be loosened. eM-TolMate [5] represents a useful tool in tolerance analysis of mechanical assemblies.