PLANNING THE ROUTING MIX IN FASS TO MINIMIZE TOTAL TRANSPORTATION TIME

The routing mix problem in flexible assembly systems is considered. Th e problem consists of assigning the operations for each part to the ma chines, with the two objectives of balancing the machine workloads and minimizing the burden of the transportation system. These two objecti ves are sometimes conflicting, since the latter tends to support assig ning operations to the same machine(s) as much as possible, and this m ay be bad for workload balancing. A linear programming problem is pres ented that, given a constraint on the workload of each machine, finds one solution that minimizes the overall time spent moving the parts fr om one machine to another. Since such a linear program may have an exp onential number of variables, an efficient column generation technique to solve the problem is devised. The efficiency of the method is vali dated by experiments on a large number of random problems.