Production Orders Sequencing in Mixed-Model Assembly Lines

The paper presents the production orders sequencing issue, which main aim is to establish a proper sequence of tasks, that would maximize the utilization of company's production capacity. According to the literature research, the sequencing problem considered in the paper, may be denoted as CSP (Car Sequencing Problem) and belongs to the NP-hard class, as has been proven by simple reduction from Hamiltonians Path problem. Optimal method of solution has not yet been found, therefore only approximate solutions have been offered. Approximate solutions are based mainly on the evolutionary algorithms. However certain problems, as lack of possibility to check the effectiveness of the solution or the possibility to reach twice the same solution are observed. Regardless of the structure of specific assembly system, while considering reception of new tasks into the execution, current review of the state of the system is obligatory in order to decide whether, when and which new order can be accepted for assembly. In this paper, the problem of task scheduling is limited to the specific existing mixed-model production system. The main goal is to determine the effective method of creation of task sequence.