Use of a Robustness Index for Flexible Facility Layout Design in a Changing Environment

*** Layout is one of the crucial issues that determine the long-term efficiency of production, and how to adjust production systems to meet fluctuating demands is extremely important. In order to enhance competitive advantages, a low-cost and robust layout is necessary so that the production systems can deal more effectively with changes of environment. This study finds the most flexible layout that has better stability for different product mix by using a Robustness Index, which is developed by integrating two factors of low-cost and robustness. Thus, the most flexible layout will remain optimal even when the product mix has changed. In additions, the fuzzy set theory is used in the Robustness Index to find the preference of each expert for low-cost and robustness together. The facility layout problem has proved out to have the characteristic of NP-complete, so the genetic algorithms that have the abilities of multi-population searching and parallel calculation are appropriate for the problem’s solution. An example illustrates the feasibility and robustness of the proposed approaches for problem-solving because the flexible layout remains optimal for the characteristics and volumes of different products.