A new method of rigid assemblies stochastic 3D tolerance analysis including thermal performance.

Abstract

Positional and orientation tolerances are specified in the components of a mechanical assembly and are of great importance in design, as they affect its quality, reliability, and cost. Tolerance analysis is a method of stacking the tolerances parts of an assembly to achieve an overall value in a given direction. The opposite approach is tolerance synthesis, or allocation, where the tolerances of the components are adjusted through a determined criterion for compliance with design constraints or for optimization purposes, such as cost reduction. The tolerance synthesis is generally performed when the results of a tolerance analysis process do not reach a design constraint requirement. The aim of this thesis is to propose a new method for tolerance analysis in a three-dimensional domain, including manufacturing simulation and consideration of functional thermal effects. A case study involving an internal combustion engine shows the efficacy of the method. Manufacturing simulation based on the Monte Carlo method provides a statistical distribution representation of process variation along a specified tolerance range. This resource can lead to optimization of the tolerance range of the mechanical assembly in each orthogonal direction and can also be a significant aid in design decisions and the selection of manufacturing processes. A feature of the proposed method is the consideration of geometric position tolerances as a function of orientation tolerances. The feature results in great accuracy at a high manufacturing volume. The method is application-oriented and can be applied effectively in the industry.

SysML4GDPSim: A SysML Profile for Modeling Geometric Deviation Propagation in Multistage Manufacturing Systems Simulation

“…to represent the maximum allowable deviations, specified as tolerance zones. Beyond tolerance representation, different mathematical models have been also proposed to deal with tolerance analysis, such as the Jacobian-Torsor model [27], the small displacement torsor [28], T-map [29], or matrix transformation [30], among others summarized in [31].…”