A study of scheduling under the theory of constraints

In this study, the implementation of the theory of constraints (TOC) rules for job-shop systems to advance the state of research on constraint scheduling is investigated. Most previous studies have applied the TOC concepts and rules to simple process flows, but the nature of job-shop systems adds complexity to scheduling. The current rules of thumb for scheduling based on the TOC are implemented for a case study in the automotive industry. A number of simulation scenarios are discussed, providing insights into the master production schedule (MPS), the drum-buffer-rope (DBR) scheduling method, the role of setup times in scheduling, the impact of free products (those that do not use constraint resources) on throughput, and the effect of priority rules in resource assignment to free products. Moreover, optimization techniques are used to find optimal and/or satisfactory solutions for input variables in the simulation experiment. Our findings suggest that the current rules of thumb should be modified for real-world applications and complex job-shop systems. (C) 2015 Elsevier B.V. All rights reserved.