An optimal operating policy for two-stage flow lines with machine failures

Automatic transfer lines, defined as an integrated system with a number of workstations, interstation storage buffers, automatic transfer device and a control system, play a major role in mass production systems. Due to high capital investment needed for an automatic transfer line, greater care should be taken in its design so as to maximize the system performance. One way to control the system performance is to control buffer storage between successive stations, and so the authors give attention to the control policy of the buffer storage. To control the interstation work-in-process inventory, they propose dual limit switches which control the buffer storage with two parameters, R and r. Under the policy, the preceding station is stopped when the inventory level in the buffer reaches R until the level falls to r. For the model developed, the authors analyze the system characteristics and find the optimal control parameters with a search procedure.