A genetic algorithm for the stochastic mixed-model U-line balancing and sequencing problem

Abstract

Mixed-model assembly lines are widely used to improve the flexibility to adapt to the changes in market demand, and U-lines have become popular in recent years as an important component of just-in-time production systems. As a consequence of adaptation of just-in-time production principles into the manufacturing environment, mixed-model production is performed on U-lines. This type of a production line is called a mixed-model U-line. In mixed-model U-lines, there are two interrelated problems called line balancing and model sequencing. In real life applications, especially in manual assembly lines, the tasks may have varying execution times defined as a probability distribution. In this paper, the mixed-model U-line balancing and sequencing problem with stochastic task times is considered. For this purpose, a genetic algorithm is developed to solve the problem. To assess the effectiveness of the proposed algorithm, a computational study is conducted for both deterministic and stochastic versions of the problem.

Keywords:

• assembly line balancing
• U-lines
• mixed-model production
• stochastic
• genetic algorithms

Acknowledgements

This research was supported by the Gazi University Scientific Research Projects Grant Number 06/2009-10. We thank the anonymous referees for their valuable comments that significantly improved the presentation of this paper.