Abstract: This research studies the joint production,
maintenance and subcontracting control policy for an unreliable
deteriorating manufacturing system. Production activities are
controlled by a derivation of the Hedging Point Policy, and given that
the system is subject to deterioration, it reduces progressively its
capacity to satisfy product demand. Multiple deterioration effects are
considered, reflected mainly in the quality of the parts produced and
the reliability of the machine. Subcontracting is available as support
to satisfy product demand; also, overhaul maintenance can be
conducted to reduce the effects of deterioration. The main objective
of the research is to determine simultaneously the production,
maintenance and subcontracting rate, which minimize the total,
incurred cost. A stochastic dynamic programming model is
developed and solved through a simulation-based approach
composed of statistical analysis and optimization with the response
surface methodology. The obtained results highlight the strong
interactions between production, deterioration and quality, which
justify the development of an integrated model. A numerical example
and a sensitivity analysis are presented to validate our results.
Abstract: The Aggregate Production Plan (APP) is a schedule of
the organization-s overall operations over a planning horizon to
satisfy demand while minimizing costs. It is the baseline for any
further planning and formulating the master production scheduling,
resources, capacity and raw material planning. This paper presents a
methodology to model the Aggregate Production Planning problem,
which is combinatorial in nature, when optimized with Genetic
Algorithms. This is done considering a multitude of constraints of
contradictory nature and the optimization criterion – overall cost,
made up of costs with production, work force, inventory, and
subcontracting. A case study of substantial size, used to develop the
model, is presented, along with the genetic operators.
Abstract: Global competition is tightening and companies have
to think how to remain competitive. The main aim of this paper is to
discuss how Finnish foundries will remain competitive. To fulfil the
aim, we conducted interviews in nine companies using castings and
analysed buyer–supplier relationships, current competitive
advantages of Finnish foundries and customer perspectives on how
Finnish foundries remain competitive. We found that the customerfoundry
relationship is still closer to traditional subcontracting than
partnering and general image of foundries is negative. Current
competitive advantages of Finnish foundries include designing
cooperation, proximity and flexibility. Casting users state that
Finnish foundries should sell their know-how and services instead of
their capacity, concentrate on prototype, single and short series
castings and supply ready-to-install cast components directly to
customers- assembly lines.