COMPUTER-AIDED OPERATIONAL DIMENSIONING FOR PROCESS PLANNING

One of the important steps of process planning is to determine the tol erance and mean size for each working dimension. This paper presents a computer-aided operational dimensioning system which can determine to lerances systematically and calculate mean sizes of working dimensions automatically for a process plan. The system is based on the toleranc e charting technique. Firstly, a tree theoretic representation for a t olerance chart is described in this paper. Three trees can be generate d from blue print dimensions, stock removals and working dimensions of a tolerance chart. The algorithms for generating the trees are provid ed, and these trees can be used to identify dimensional chains and sol id stock removals in a tolerance chart. Then a linear programming mode l is built to determine the tolerance of each working dimension. Final ly, a mathematical model of linear equations for calculating mean work ing dimensions is formulated from the dimensional chains.