Balancing assembly lines withvariable parallel workplaces:Problem definition, model andexact solution procedure

Assembly line balancing problems (ALBP) arise whenever an assembly line is configured,redesigned or adjusted. An ALBP consists of distributing the total workload for manufacturingany unit of the products to be assembled among the work stations along the line subjectto a strict or average cycle time. Traditionally, stations are considered to be manned by oneoperator, respectively, or duplicated in form of identical parallel stations, each also manned bya single operator. In practice, this assumption is usually too restrictive. This is particularly truefor large products like cars, trucks, busses and machines, which can be handled by several operatorsperforming different tasks at the same time. Only restricted research has been done onsuch parallel workplaces within the same station though they have significant relevance in realworldassembly line settings.In this paper, we consider an extension of the basic ALBP to the case of flexible parallel workplaces(VWALBP) as they typically occur in the automobile and other industries assemblinglarge products. The problem is defined and modelled as an integer linear program. As a solutionapproach a branch-and-bound procedure is proposed which also can be applied as a heuristic.Finally, computational experiments documenting the solution capabilities of the procedure arereported....