A research on two-stage production line building problems for processed cheese manufacturing

Production line design is one of the important research topics for constructing smart factories. Many research papers have been published concerning smart factories; however, most of them are focus on subjects such as automation. IoT (Internet of Things), AI (Artificial Intelligence) and other new technologies that are introduced to increase the efficiency of existing manufacturing lines based on the so-called philosophy of " status-quo improvement " . In this research, we consider a design problem for a new production line taking into consideration investment cost, operation cost, synchronization penalty and flexibility penalty. We emphasize synchronization and flexibility as new key performance indices to evaluate the level of intelligenced to the smart factory, in which a multiple number of equipment in two production processes can provide the proper number of combinations to satisfy the external demand remove. Based on a real case involving a major player in the dairy product processing industry in Japan, we focus on two core production processes in a processed cheese manufacturing line; melting process and filling process. We design the process to include investing in a multiple number of machines with different capacities, while minimizing the total cost giving consideration to investment, operations, synchronization and flexibility. Two types of decision variables are introduced representing investment and operation. Through numerical experiments and the case study, we show that the proper number of equipment and capacity can be obtained applying the proposed model. The proposed model can also be applied to those companies considering further investment in factory or production line.