A U-shaped production line with multiple machines and multiple workers is considered under carousel allocation in which all workers take charge of all machines in the same order. Nakade and Ohno (2003) show that, when the processing, operation and walking times are constant, the overall cycle time, which is a time interval between successive outputs of finished goods, is the greatest value of the maximal sum of the processing and operation times among machines and the time required for a worker to operate and walk around the production line without waiting for processing divided by the number of workers. In this paper, it is considered that operation times at each machine may be different between workers. If processing time is short, it is expected that the overall cycle time will be equal to the time for a worker to operate and walk around the line divided by the number of workers. However, under some specified cases, the overall cycle time is longer than that of this time, and the overall cycle time changes periodically. From numerical examples, it is shown that the order of arrivals of workers at machine 1 affects the overall cycle time. We give some properties on the periodicity of cycle times and discuss about cycle times
Production control such as the base stock policy, the kanban policy and the constant work-in-process policy in a serial production line has been studied by many researchers. Production lines, however, usually have fork-type, join-type or network-type figures. In addition, in most previous studies on production control, a finished product is required at the same time as arrival of demand at the system. Demand information is, however, informed before due date in practice. In this paper a join-type (assembly) production line under base stock control with advanced demand information in discrete time is analyzed. The recursive equations for the work-in-process are derived. The heuristic algorithm for finding appropriate base stock levels of all machines at short time is proposed and the effect of advanced demand information is examined by simulation with the proposed algorithm. It is shown that the inventory cost can decreases with little backlogs by using the appropriate amount of demand information and setting appropriate base stock levels.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.