Mass productio!l and mass consumption, so far considered virtues in a
free economic soceity, have changed. Various problems have occurred
including economic stagnation, energy crisis, shortage of material
resources, prolifera- tion of pollution, lack of skilled labor, rapid
changes of product design, technical innovation, and others. Moreover,
individual manufacturing firms must take steps to adopt multi-product,
small-lot-sized (batch type) produc- tion as a type of production in
order to adapt themselves to a market movement characterized by a
diversified and specialty-oriented society and a short product life
cycle. The number of manufacturing firms worldwide that use a type of
multi-product, small-lot-sized production is expected to increase. This
is so even in the United States, which has been said to be a country of
mass production. Multi-product, small-lot-sized production has been
considered to be a milestone to flow-type mass production, which has
been thought to be the most effective production system. Intensive
efforts have been made to investigate mass production systems from both
theoretical and practical viewpoints. Few studies have been made for
multi-product, small-lot-sized production (batch-type manufacturing).
Considering the present business circumstances faced with various
difficulties, it is strongly required to establish some theories useful
for making practically effective and flexible multi-product,
small-lot-sized production systems. Several effective approaches to the
batch-type manufacturing systems have been developed. Group technology
(GT) is one such method that has steadily obtained great interest from
progressive manufacturing firms all over the world.