This thesis reports research carried out into a novel approach to the operational planning of
discrete component manufacturing lines used in the automotive supply industry. The work
is based on extending the functionality of the state of the art automotive component
manufacturing lines known more commonly as flexible manpower lines (FMLs). This
extended system is termed a multi-component flexible manpower line (MCFML) and has
the capability to produce a wider range of components than a FML at lower production
costs. A major requirement of MCFMLs is to offer the flexibility and responsiveness to
meet often unpredictable orders that can vary in terms of part variety and volume
requirements on a daily basis. Traditional production planning and control approaches do
not offer the capability to support MCFMLs, therefore this research explores the use of a
specially tailored operational planning system, based on a hybrid just-in-time (HyJIT)
approach which relies on safety stock to cope with fluctuations in demand.
The research contribution identifies and defines a HyHT operational planning
framework, consisting of finite capacity production planning (FCPP) and inventory control
(IC) activities. Most significantly, as part of the inventory control activities, five stock
management rules (SMRs) have been developed that determine the provision of safety
stock to support production and minimise associated costs. The applicability of this novel
framework has been underpinned by the design and implementation of a HyJIT software
toolkit and a set of experiments that test the performance of the SMRs under various
MCFML scenarios (varying in terms of order requirements and stock conditions).
The HyJIT operational planning approach is shown to be an effective method to
balancing MCFML resource utilisation using minimal inventory to support often volatile
orders. In particular the results show that the HyJIT approach provides significant cost and
time benefits over a commonly used existing stock management concept. Most
importantly, this research shows that the strategic utilisation of safety stock in a just-intime
(HT) environment is a feasible and effective solution to allow automotive suppliers to
become more competitive and to satisfy the customised demands of today's marketplace.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.