Production planning is an important factor for production efficiency in the shipyard. However, planning is currently executed by manual operations based on the experience of field workers because of the complexity of the target shipbuilding project. This paper proposes a method of creating a realistic production plan automatically by modeling the complex shipbuilding project and using the developed process simulation. Specifically, we propose a method to represent the target shipbuilding process by four system models—Product, Workflow, Workplace, and Team. By executing the developed process simulation using system models, a Gantt chart can be created as a realistic production plan. From the case studies of a virtual shipyard manufacturing a ship hull block, it can be said that the proposed method can create a good production plan considering the complexity of the target shipbuilding project. In addition, the proposed method can evaluate the bottleneck of the target shipyard and the re-allocation plan for workers quantitatively.

In the field of high-mix low-volume production, to keep shipping deadline of each order is one of key factors due to the reason for make-to-order production. However, this type of production has a enormous number of parts to be handled, complicated work procedures, and many restrictions on production resources. Therefore, it is difficult to make an optimal production plan considering shipping deadline and efficient usage of production resources. In this paper, the objective is to create work plans which meet the due date with short lead times as much as possible in a job shop type production line. First, we propose the method how to model and represent the complex data of an entire factory structure. Then, based on this model, it was proved that we can obtain the production plan with short lead times that emphasizes compliance with the sequence of product shipping by backward discrete event simulation. Furthermore, the effectiveness of the proposed method and the validity of the obtained production plan are confirmed by using actual factory processes and real data.

Shipbuilding is one of the most complex production systems in the manufacturing industry because of the incredible variety of parts and highly complex processes. However, production plans are currently prepared manually depending on the experience of expert workers. In this paper, a production planning method based on shipbuilding process simulation is proposed for use in actual shipyards, which simultaneously satisfies the needs of both production managers, who require on-time delivery plans, and field workers, who aim to minimize waiting time and improve operating rates. Specifically, the authors developed a hybrid method that combines backward and forward simulation for planning front-loading to meet deadlines and reduce waiting time. In the case study, the method was applied to a sub assembly conveyor line in an actual shipyard to demonstrate the validity and feasibility of the simulation results.