Page 195 - Modular design for machine tools

Application of Machine Tool Description to Engineering Design 155

1.0

Available region for
unit construction

Available region for
Rate of commonness 0.6
real modular design

0.5

Region not
applicable to
modular
design

0
0.5 0.6 0.8 1.0
Rate of similarity
Figure 4-21 Schematic representation of available range of modular
design systems.

functional aspect of the part, where upper and lower rows show the
function and shape entities.
The similarity evaluation can be carried out using the two charac-
teristics, i.e., commonness rate to evaluate the number of identical
shape entities and the allocating order rate to evaluate the similarity
of the allocating order of the common entities between both parts. More
specifically, the commonness rate can be calculated by using the refer-
ence matrix shown together in Fig. 4-22, where the (i, j) component
yields the following:

Identical shape entity with identical function unit
Entity in part identical 0.5
Entity completely not identical nil

and
Consequently, from the reference matrix, the distribution rate Q d
the commonness rate S yield
r
Q di/(p dM) (0 Q unit, i 1 p) (4-4)
e
d
number of identical entities
where p e
di deviation distance from diagonal line in reference matrix
dM maximum value of di