Abstract:
Supply Chain Management (SCM) is a necessary concept for manufacturing
firms as it deals with the coordination and integration of
interactions among collaborating suppliers to realise products. One
crucial aspect of SCM is supplier selection. Organisations not only need
to decide whether to keep the design and development of a product
in-house or outsource, but they also need to be able to distinguish
among potential suppliers in order to improve their Supply Chain
performance. The Product’s Architecture is important to incorporating
those interactions as it is typically established at the early stages of
Product Development and impacts on the costs of collaboration within
the Supply Chain. These decisions should be incorporated into the
product design phases due to the two-way implications of the Product
Architecture (PA) and its associated Supply Chain.
However, despite the significance of this two-way interaction, previous
research on this topic has focused mainly on the production stages
of Product Development, and only a few studies have considered the
supplier selection issue during the Product Design (PD) phases with
the vast majority of those studies commencing at the later stages of
PD (i.e. the detailed design phase of PD). Limited research exists at
the early stages of PD and in particular the preliminary phase of PD
where the PA is established. Moreover, this stage usually consists of
uncertain data that managers have to work with and as such a method
that can incorporate some element of uncertainty into the decision
making is lacking. As a result, there is a pressing need to explore this
issue further.
In this thesis, a method was presented to integrate PA and Supply
Chain Configuration (SCC) decisions. It begins with the PD aspect that
analyses different chunk aggregation decisions of the PA, which then
serves as a bridge connecting the different aggregated components
and chunks to the suppliers. Then the supply chain aspect is analysed
by looking at the performances of the different SCC under the different chunk aggregations. An Integer NonLinear Programming (INLP)
model was then developed as it was deemed suitable to solve this. This
INLP model was further extended to a stochastic model to incorporate
for uncertainty in decision making in the early stages and explore if
considering uncertainty early enough in decision making provided
substantial benefits to the decision-makers.
The developed INLP model was then evaluated by using a reverseengineered
printer case study. The results obtained showed that it was
beneficial for the Focal Company (FC) to incorporate SCC to the early
design stages as this has implications on what PA the FC should select.
The results also outlined what outsourcing strategy the FC should
use when selecting suppliers. Also, the impact of different supplier
characteristics on the decision of how the FC should aggregate the
PA was tested. The results showed it is important for the FC to consider
the different supplier characteristics when making PA decisions.
Lastly, the INLP model was extended to a stochastic model to include
uncertainty by varying the cost. The results were analysed using the
concept of Expected Value of Perfect Information (EVPI), which is a
well-established concept in tackling uncertainty. The results showed
that it was beneficial for the FC to include uncertainty in decision
making at the early stages of design.
Finally, the model was tested via sensitivity analysis to validate the
use of the model in this research—the sensitivity analysis aimed to
test the behaviour of the model by varying different parameters in the
model. After varying the data, the model produced the same results,
which suggests the suitability of the use of the model. As a result, the
optimisation of the Supply Chain (SC) and PA can be simultaneously
accomplished during the preliminary design stages.