  The 3 stage reducer problem is a point of interest for many researchers. In
this paper, this problem is reformulated to a bi-objective problem with
additional constraints to meet the ISO mechanical standards. Those additional
constraints increase the complexity of the problem, such that, NSGAII
performance is not sufficient. To overcome this, we propose to use BnB-NSGAII
method - a hybrid multi-criteria branch and bound with NSGAII - to initialize
NSGAII before solving the problem, seeking for a better initial population. A
new feature is also proposed to enhance BnB-NSGAII method, called the legacy
feature. The legacy feature permits the inheritance of the elite individuals
between - branch and bound - parent and children nodes. NSGAII and BnB-NSGAII
with and without the legacy feature are tested on the 3 stage reducer problem.
Results demonstrate the competitive performance of BnB-NSGAII with the legacy
feature.
