On Periodicity of Cycle Time of a U-shaped Line in Chase Mode

Abstract

A U-shaped line with multiple machines and workers in chase mode is considered. In this line, several heterogeneous workers deal with all tasks and walks around in the same line. When a worker catches up the front worker, the former has to wait for the latter leaving the machine by finishing the task there. Task times of each task are different among workers because of their experience. In this model, some periodicity on the cycle time is found for one example in Hiraiwa and Nakade (2009). In this paper, the periodicity of cycle time of a U-shaped line in chase mode is more deeply discussed. It is shown that if there are just two workers then there is no periodicity of cycle time. Examples for three or more worker cases show that the order of workers on the line sometimes highly influences on the length and periodicity of cycle time. By changing the task time of some worker, many types of periodicity are found.