Dynamic Scheduling of Batch Operations with Non-Identical Machines

Batch-wise production is found in many industries. A good example of production systems which process products batch-wise are the ovens found in aircraft industry and in semiconductor manufacturing. These systems mostly consist of multiple machines of different types, given the range and volumes of products which have to be handled. Building on earlier research in aircraft industry, where the process of hardening synthetic aircraft parts was studied, we propose new strategies for the dynamic control of these type of systems: These socalled 'look-ahead strategies' base their decision to schedule a job on a certain machine upon the availability of information on a few near future arrivals. Moreover, a general method is presented, which shows how such strategies may be constructed. Through simulation the performance of the new control strategies was demonstrated in terms of logistical costs for several system configurations. Results of these simulations are compared with those for alternative strategies. Next to the information on relative performance of the control strategies also valuable new insights were obtained with regard to the relationship between system configuration and its performance. As an important special case the effect of machine grouping on system performance is studied.