A tolerance analysis and optimization methodology. The combined use of 3D CAT, a dimensional hierarchization matrix and an optimization algorithm

Abstract

We propose a methodology in this study for the analysis and the optimization of assembly tolerances. A combination of three components, it involves the use of 3D CAT software, a table referred to as a "dimensional hierarchization matrix", and a tolerance optimization algorithm. The Antolin Group, a Spanish multinational in the automobile components sector, employs this system to optimize tolerance values and to reduce manufacturing costs. The matrix was designed to enable easy identification, in a single table, of all requirements that fail to meet the specifications in the different approximations, prior to the definition of the dimensional and the geometric tolerances that comply with the functional requirements, and to identify which tolerances contribute most to variations in all of the functional conditions of the mechanism. Through its different iterations, this matrix allows us to see which of the tolerances should first be modified to optimize the design requirement specifications. A tolerance optimization algorithm was also defined, which functions with the data from the dimensional hierarchization matrix.

Allocation of geometric tolerances in one-dimensional stackup problems

“…One of the most popular choices is the use of commercial computer-aided tolerancing (CAT) software to verify stackup constraints for each candidate set of geometric tolerances. Software simulation is integrated with several optimization strategies; they include design-of-experiments (DOE) approaches such as full factorial plans [32,33] or response surfaces [34,35], solution search methods such as genetic algorithms [36,37], and the improvement of an initial solution through interactive procedures [38,39]. For an unusual formulation of the allocation problem without cost-based optimization [40], simulation drives the selection of solutions in a constraint space defined by applicable functional requirements.…”

New Integrated TBM Disc Cutter Deviation Analysis And Design of The Supporting Cutter-Changing Robot End-Effector

“…The 3-D tolerance analysis technology is very suitable for the deviation analysis of complex assembly [13,14]. Common 3D tolerance analysis models include Small Displacement Torsor model [15][16][17], T-Map model [18,19], Matrix model [20], Unified Jacobian-Torsor model, SDT [21][22][23] and DLM (Direct Linearization Method) [13,24].…”