A novel line balancing problem is considered. It differs from assembly line balancing problems in that the operations of each workstation are partitioned into blocks of simultaneously executed (parallel) operations. The blocks of each workstation are executed sequentially. For the line design stage considered in this paper, the compatibility (inclusion and exclusion) constraints for grouping operations into blocks and workstations as well as precedence constraints are known. The goal is to minimize a weighted sum of the number of workstations and the number of blocks while achieving a desired cycle time and satisfying all the constraints. The developed exact and heuristic methods are based on a mixed-integer programming approach. Experimental results are reported.
International audienceThe paper deals with optimal balancing transfer lines where the operations in each workstation are grouped into blocks. All operations of the same block are executed simultaneously by one spindle head. Spindle heads of the same workstation are activated sequentially. The workstation time is the sum of the processing times of its blocks. The problem is to find the best assignment of operations to blocks and assignment of blocks to workstations that leads to the minimal transfer line cost (a weighted sum of blocks and workstation numbers). The solution must provide a desired productivity rate (cycle time). It must also satisfy precedence and compatibility constraints. Two heuristic algorithms based on the COMSOAL technique are proposed. Results from computer testing are reported
International audienceThe paper deals with optimal logical layout design for a type of machining lines. Such lines are made of many machine-tools (workstations) located in sequence. On each workstation there are several multi-spindle heads. A spindle head does not execute one operation but a block of machining operations simultaneously. The problem studied in this paper consists of finding the best partition of the set of all operations to be executed on the line into blocks and workstations. The objective is to minimize the number of blocks and workstations. An optimal decision must satisfy a desired productivity rate (cycle time) and precedence and compatibility constraints for machining operations. A heuristic approach based on decomposition of a Mixed Integer Programming (MIP) model is developed. Two ways of forming sub-problems are proposed. One treats the obtained subsets independently. The second aggregates the solution of the previous subproblems. Results of their computational evaluation are reported
The optimal logical layout design for a type of machining transfer lines is addressed. Such transfer lines are made of many machine-tools (workstations) located in sequence. On each workstation there are several spindle-heads. A spindle-head does not execute a single operation but a block of machining operations; all operations of a block are executed simultaneously (in parallel). Spindle-heads of the same workstation are activated sequentially in a fixed order. The transfer line design problem considered in the paper consists of finding the best partition in blocks and workstations of the set of all operations to be executed on the line. The objective is to minimize the number of spindle-heads and workstations (i.e. transfer line investment cost). An optimal decision must satisfy a desired productivity rate (cycle time) as well as precedence and compatibility constraints for machining operations. A heuristic algorithm is proposed: it is based on the COMSOAL technique and a backtracking approach. Results from computer testing are reported.
International audienceFlow lines are widely used in mechanical industry. They consist to a set of workstations through which parts are manufactured. Designing such a line is a very complex problem due to manufacturing and design constraints and to the large number of possible decisions. Usually, the design of this type of production lines involves the selection of the necessary operations (indivisible units of work) to machine a part, the configuration design, the line scheduling. In this paper we present a survey of flow lines balancing problem, their approach and formulation and some solutions to optimize them studied in the literature. A special attention is paid for the assembly lines balancing problems
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