A hybrid policy to correct for the selectivity of order acceptance procedures in batch process industries

Customer order acceptance is an important process in make-to-order industries. Acceptance policies should operate such that a pre-specified delivery reliability is achieved, while maximizing resource utilization. By selecting orders with specific characteristics that maximize resource utilization, an important and often unforeseen effect occurs: the mix of orders changes such that the expected delivery reliability is no longer met. This paper investigates the selectivity of an aggregate and a detailed acceptance procedure, for batch process industries featuring complex job and resource structures. We found that the detailed policy maximizes resource utilization but underestimates the consequences on the realized makespan of significantly changing the job mix. The aggregate policy, while being selective, performs much better with respect to the delivery reliability, but achieves a lower capacity utilization. We propose a third procedure, the hybrid policy, which combines the strengths of both the detailed and aggregate acceptance procedures. Simulation experiments show that the hybrid policy successfully controls the delivery reliability, without loosing much of the beneficial effect of the selectivity on utilization.