Part Family Formation

Part family formation is the procedure of grouping similar parts depends on predetermined attributes. For instance, parts might be classified on the basis of geometric shapes, type of operation, dimensions, etc. In a mono code structure a family is defined as a collection of "end-twigs" and their common node.

To enhance the part family size, we ought to move to the next node & include all branches attached at that point .This process may become cumbersome.

                Figure: Mono Code System of Classification

In case of poly codes, for manufacturing applications, part families are determined on the basis of manufacturing attributes.

Suppose we want "f" number of families to be identified from a set of "P" parts for the desired objective function. Normally the objective function is formulated on the basis of distance measure. Distance measure diagram between path i and j is a real valued symmetric function with the following characteristics:

Reflexivity, d_ii = 0

Symmetry, d_ij = d_ji

Triangle inequality, d_iq ≤ d_ip + d_pq

Absolute value of d_ij can be defined by

Equation

Where, X_ik = k^th attribute value of part i,

            X_jk = k^th attribute value of part j, and

              K = No. of digits of the coding system.