Priority Scheduling for a Flexible Job Shop with a Reconfigurable Manufacturing Cell

摘要

This paper considers a scheduling problem in a flexible job shop with a reconfigurable manufacturing cell. The flexi- ble job shop has both operation and routing flexibilities, which can be represented in the form of a multiple process plan, i.e. each part can be processed through alternative operations, each of which can be processed on alternative ma- chines. The scheduling problem has three decision variables: (a) selecting operation/machine pairs for each part; (b) sequencing of parts to be fed into the reconfigurable manufacturing cell; and (c) sequencing of the parts assigned to each machine. Due to the reconfigurable manufacturing cell’s ability of adjusting the capacity, functionality and flexi- bility to the desired levels, the priority scheduling approach is proposed in which the three decisions are made at the same time by combining operation/machine selection rules, input sequencing rules and part sequencing rules. To show the performances of various rule combinations, simulation experiments were done on various instances generated ran- domly using the experiences of the manufacturing experts, and the results are reported for the objectives of minimiz- ing makespan, mean flow time and mean tardiness, respectively.