Development of procedure of process design to aim to promote productivity for mix production (Influence of fluctuation of operation time and buffer)

Abstract

In recent production environment, many factories introduce mixed production system to simultaneously produce multi-types of products. Ordinarily, multiple work elements are assigned to workers or work centers in the process of process design to aim at high productivity. However, fluctuation of operation times is normally included in mixed production line and capacity of buffer affects productivity of the line. In this study, we deal with the problem of process design for mixed production line including fluctuation of operation time. In addition, we treat the problem of process line as multi-objective problem. In this paper, multi-objective genetic algorithm is developed to resolve the problem to minimize the bi-objective functions: the maximum value of operation time at all work centers and the maximum value of dispersion of operation time all work centers. Numerical experiments are performed to evaluate performance of the algorithm and characteristics of solutions. Productivity of the production line designed by the proposed algorithm is evaluated by using event-driven simulation. Simulation result shows that production line designed by the proposed mathematical model generates high productivity and small size of WIP when buffers are located between work centers.

Keywords

• process design
• multi-objective genetic algorithm
• simulation
• variation of operation time
• mathematical model
• productivity