Gomes, Marta C.Barbosa-Póvoa, Ana PaulaNovais, Augusto Q.2014-03-172014-03-172013Gomes, Marta C.; Barbosa-Póvoa, A.P.; Novais, Augusto Q. Reactive scheduling in a make-to-order flexible job shop with re-entrant process and assembly: a mathematical programming approach. In: International Journal of Production Research, 2013, Vol. 51, nº 17, p. 5120-51410020-7543http://hdl.handle.net/10400.9/2323A mixed-integer linear programming model is presented for the scheduling of flexible job shops, a production mode characteristic of make-to-order industries. Re-entrant process (multiple visits to the same machine group) and a final assembly stage are simultaneously considered in the model. The formulation uses a continuous time representation and optimises an objective function that is a weighted sum of order earliness, order tardiness and in-process inventory. An algorithm for predictive-reactive scheduling is derived from the proposed model to deal with the arrival of new orders. This is illustrated with a realistic example based on data from the mould making industry. Different reactive scheduling scenarios, ranging from unchanged schedule to full re-scheduling, are optimally generated for order insertion in a predictive schedule. Since choosing the most suitable scenario requires balancing criteria of scheduling efficiency and stability, measures of schedule changes were computed for each re-scheduling solution. The short computational times obtained are promising regarding future application of this approach in the manufacturing environment studied.engReactive schedulingFlexible job shopRe-entrant processAssemblyMixed-integer linear programjournal article