Work order release and input sequencing for a printed circuit board assembly cell

The problem of work order release and input sequencing for a printed circuit board assembly cell is addressed. Some of the placement machines in the assembly cell are highly flexible and their setup is changed according to the component requirements of released orders. The selection of work orders to form a new batch to be released into the shop floor and the sequencing of individual orders within a batch are two problems which are solved repeatedly. For solving the work order selection problem a MILP model is solved and its results for the overall system performance are compared to a bottleneck oriented heuristic. The system performance is measured by a simulation model of the respective cell. In addition, local dispatching and sequencing rules are applied within the simulation model in order to model the material flows. The computational experiments start with evaluating the different work order selection procedures. A numerical study for different order arrival processes is conducted and the contribution of input sequencing to the system performance is discussed. The experiments are based on concrete industry data.