Tolerance chart optimization

Abstract

A tolerance chart is a graphical representation of a process plan and a manual procedure for controlling tolerance stackup when the machining of a component involves interdependent tolerance chains. This heuristic, experience-based method of allocating tolerances to individual cuts of a process plan can be embodied in a computer-based module. This paper introduces a graph theoretic representation for the tolerance chart. A special path tracing algorithm is used to identify tolerance chains from this graph. Optimal tolerance allocation among individual cuts is achieved using a linear goal programming model instead of existing heuristic methods. A 1D0re comprehensive mixed integer programming model is developed to incorporate' linear tolerance cost functions and alternative process selection.

The apparent path tracing approach to tolerance charting

“…It incorporates a matrix tree chain method for generating tolerances and calculating the working tolerances as well as for making the necessary adjustments to meet the blueprint requirements. Irani et al [5] then presented one of the most comprehensive methods of tolerance optimisation, but…”

Nonlinear optimisation in tolerance charts ? A study of objective functions

“…Weill [7] presented a systematic approach to track the process links with the aid of a tolerance matrix. Tolerance budgeting was then carried out by apportionment, trani et al [8] proposed a graph-theoretic approach to track the process links whereby constraint equations were set up and solved using the goal-seeking linear programming method.…”

Process-based tolerance assessment of connecting rod machining process

“…Primitive studies on process tolerancing were introduced through graphical representation of machining tolerance charting (Irani et al 1989). The graphical approach and rooted tree diagram were adopted for tolerance charting (Whybrew et al 1990).…”