5. Conclusions
In this study, simulation and modelling of the loading and the unloading systems in a
warehouse that involves ready packed as well as products that need sealing has been
conducted using ARENA. As expected, the unloading system involving the use of the
company’s own lorry which is well scheduled, is functioning satisfactorily. On the other hand,
the loading system has been identified to have the long waiting times for the OPSL and the
loading processes. Therefore four improvement models have been experimented with in order
to find a strategy that will optimise the residence time of any customer’s lorry without
affecting the other processes. Out the four models, model IM2 where the arrival of lorries is
scheduled and an additional forklift and a driver have been used, has produced the best results.
It has not only overcome the overtime problem but also reduces the waiting time of the
customers by almost two hours, i.e. by more than 65%, and reduces the waiting time in the
OPSL process by more than 70%. Furthermore, the fact that the simulation is done for a
twelve-hour period also means that overtime is not needed. However, since this work does not
consider cost and profit, it is worth considering this issue in further investigation.