Akademik Veri Yönetim Sistemi
Sigma Journal of Engineering and Natural Sciences, cilt.3, sa.39, ss.313-321, 2021 (ESCI)
Just-in-time (JIT) delivery is one of the key delivery strategies that enable the right quality
product to reach the point of demand at the right time without creating unnecessary costs in
the supply chain network. The concepts of quality and time are two main factors to be considered
in this issue. Particularly because the variability in quality directly affects cost and time,
it is very important for JIT delivery. In this study, the effect of raw material quality within the
supply chain network which tries to ensure JIT delivery is examined. For this, a multi-stage,
multi-period mixed-integer mathematical model is proposed in the study. The model aims to
minimize the total supply chain cost by trying to balance the purchasing and quality costs for
manufacturers. In addition to standard constraints, the stock balance and time constraints
have been developed for JIT delivery. As a result of the model resolved with the GAMS Distribution
21.6 program, 34.5% of the raw material supplied from suppliers is provided from
1st quality raw materials, while 65.5% is provided from 2nd quality raw materials. Despite its
low purchasing costs, 3rd quality raw material has not been preferred by the producers in any
period because it causes a delay in JIT delivery. Besides, it is seen that deliveries are made very
close to the maximum delivery time of distribution centers, depending on the variability in
raw material quality. It is understood that raw material quality is an important concept in a JIT
supply chain network due to its significant impact on time.