The Impact of Walking Time on U-Shaped Assembly Line Worker Allocation Problems

The one-piece flow manufacturing line of single and customized products is usually organized as a U-shaped assembly layout. In this study, the characteristics of a single U-line are described and modeled. The worker allocation problem is hierarchically concerned with the task assignment into a U-line and allocate task to workers in sequence. Several products are assembled in 7-task to 297-task problems, and each problem is performed with a given cycle time. The primary purpose is to identify the impact of walking time on both symmetrical and rectangular U-shaped assembly layouts. The minor purpose is to compare the number of workers between two fixed layouts. Coincidence algorithm demonstrates clarifying solutions. To respond to two previous aims, the primary objective function of a number of workers is used. Finally, with the Pareto-optimal frontier between the deviation of operation times of workers and the walking time, its computational study is exemplified to identify good task assignment and walking path.