Feature Issue of the European Journal of Operational Research http://www.elsevier.com/homepage/sae/orms/eor/menu.htm
Title: Balancing Assembly and Transfer Lines
Deadline: May 1, 2002
Guest editor: Professor Alexandre Dolgui, University of Technology of Troyes (France), E-mail: dolgui@utt.fr
The aim of the special issue is to present mathematical models and methods for generalized production line balancing problems. This problem arises at the preliminary design stage of production lines. The presented methodology will be oriented to goods manufacturing. Advanced exact and approximate methods of scalar and multi-criteria optimization taking into account various design objectives as well as technical and cost constraints will be discussed.
The line balancing problem is one of the most important problems of preliminary design stage for flow-line production systems. This problem was generally studied for assembly lines with a relatively simple structure. A detailed analysis of the assembly line balancing problem is given in the book of Dr. A. Scholl (Springer Verlag, 1999). For a given set of manufacturing operations and a given cycle time, the classical line balancing problem consists in assigning each operation to a workstation such that the number of workstations is minimized and precedence constraints are satisfied. The workstation time (which is the sum of times of all operations of this workstation) must not exceed the given cycle time. A difference between the cycle time and workstation time is called idle time. The sum of idle time for all workstation is called balance delay time. The balance delay time will be minimal if and only if the number of workstations is minimal too. The dual problem is minimization of the cycle time for a given number of workstations.
A generalized line balancing problem consists of distributing operations among workstations while minimizing some criteria different than number of workstations (cost, productivity, reliability, maintainability, etc.) and taking into account some additional constraints.
In this special issue, generalized line balancing problems will be presented for large class of production lines including lines with complex structure (for example, transfer lines with grouped tools). New methods will be also discussed for mechanical production lines where machining modes are decision variables of the problem (processing times depend on the machining modes) or for assembly line where selection of equipment is made in the same time than line balancing.
For robotics assembly lines, there are some additional balancing problems, for example positioning of robots in the lines. These problems are also a topic of this special issue.
Many models for optimal line balancing are deterministic, the processing times are supposed to be fixed. So, in this special issue some results will be presented for stability of optimal solutions analysis of line balance for the lines where the processing times are not deterministic parameters.
Finally, production line balancing has usually several important criteria such as productivity, availability, investment costs, labor costs, utility costs, maintenance costs, etc. Line balancing tools capable of taking into account these criteria will be discussed. In this case, Pareto approach for multi-criteria optimization is a natural tool for dealing with various competing objectives of design problems.
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Prof. Alexandre DOLGUI
Dépt. Génie des Systèmes Industriels (GSI) Lab. d'Optimisation des Systèmes Industriels (LOSI) Université de Technologie de Troyes (UTT) 12, rue Marie Curie B.P. 2060 10010 TROYES Cedex France
Tel. : (33) 3 25 71 56 29 Fax : (33) 3 25 71 56 49
E-mail : dolgui@utt.fr __________________________________________________ ********************************************* Nouvautés : http://www.utt.fr/mosim01 http://www.utt.fr/jim
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