Minimizing total flow time on a single flexible machine

Karakayali, Ibrahim
Azizoğlu, Meral
In this study, we address a job sequencing and tool switching problem arising in flexible manufacturing systems. We consider the single machine problem of minimizing total flow time. We prove that the problem is NP-hard in the strong sense and show that the tool switching problem is polynomially solvable for a given sequence.


Minimizing the number of tool switching instants in Flexible Manufacturing Systems
Konak, Abdullah; Kulturel-Konak, Sadan; Azizoğlu, Meral (Elsevier BV, 2008-12-01)
In this study, we address a part-type sequencing and tool switching problem arising in Flexible Manufacturing Systems. We consider the single machine problem of minimizing the number of tool switching instants. We propose two tabu search approaches to find high-quality solutions. Our computational results reveal that both tabu search approaches produce optimal or near-optimal solutions in reasonable times.
Rebalancing the assembly lines with total squared workload and total replacement distance objectives
Girit, Utku; Azizoğlu, Meral (Informa UK Limited, 2020-01-01)
Assembly line balancing is an important and well recognised operations research problem. The current line balance may not stay optimal, even feasible, due to the disruptions in one or more workstations. In this study, after the disruption, we aim to rebalance the assembly line by considering the trade-off between workload balancing (fairness measure) and total replacement distance for the tasks assigned to the different workstations (stability measure). We try to generate all non-dominated objective functio...
Capacity allocation problem in flexible manufacturing systems: branch and bound based approaches
ÖZPEYNİRCİ, SELİN; Azizoğlu, Meral (Informa UK Limited, 2009-01-01)
This study considers an operation assignment and capacity allocation problem that arises in flexible manufacturing systems. The machines have limited time and tool magazine capacities and the available tools are limited. Our objective is to maximise total weight of assigned operations. We develop a branch and bound algorithm that finds the optimal solutions and a beam search algorithm that finds high quality solutions in polynomial time.
Machining conditions-based preventive maintenance
Akturk, M. Selim; Gürel, Sinan (Informa UK Limited, 2007-01-01)
In this study we propose an operating conditions-based preventive maintenance ( PM) approach for computer numerical control (CNC) turning machines. A CNC machine wears according to how much it is used and the conditions under which it is used. Higher power or production rates result in more wear and higher failure rates. This relationship between the operating conditions and maintenance requirements is usually overlooked in the literature. On CNC turning machines we can control the machining conditions such...
Dissimilarity maximization method for real-time routing of parts in random flexible manufacturing systems
Saygin, C; Kilic, SE (Springer Science and Business Media LLC, 2004-04-01)
This paper presents a dissimilarity maximization method (DMM) for real-time routing selection and compares it via simulation with typical priority rules commonly used in scheduling and control of flexible manufacturing systems (FMSs). DMM aims to reduce the congestion in the system by selecting a routing for each part among its alternative routings such that the overall dissimilarity among the selected routings is maximized. In order to evaluate the performance of DMM, a random FMS, where the product mix is...
Citation Formats
I. Karakayali and M. Azizoğlu, “Minimizing total flow time on a single flexible machine,” INTERNATIONAL JOURNAL OF FLEXIBLE MANUFACTURING SYSTEMS, pp. 55–73, 2006, Accessed: 00, 2020. [Online]. Available: