Abstract
This paper deals with a design optimization process with some experiments that are often
executed in design and development phase. In order to avoid repetition of experiments as possible,
Taguchi method has been proposed from a view point of robustness. And, Nakazawa method has been
proposed from a view point of optimal balance among multi-required specifications. However, these
methods have not been used together in practical engineering fields although bothmethods commonly
use the orthogonal array in the experimental design. There are rare studies of combinational use to
make the most of characteristic points of the both methods. In this paper, the characteristic points of
these methods are examined and arranged first. Then, an efficient combinational use of these methods
is proposed. A simple case study shows that the proposed method is useful for practical design and
development processes.