This research concentrates on the buffer specification problem of the design of asynchronous assembly systems (AAS). The objectives of the research are to determine an optimal area of buffers and to design AAS that are robust to noise factors. In order to determine an optimal area of buffers in which the throughput yields to maximum, the design of experiments (DoE) approach and discrete-event simulation are used, and appropriate buffer levels are identified accordingly. Studies indicated that determining an optimal area provided the design engineer the much needed flexibility to choose the buffer sizes within a range. The DoE approach also offered substantial information on the AAS that can serve the design engineer as an invaluable guideline and enable one to design the AAS with a better understanding. Furthermore, the use of DoE approach as an optimization tool is proposed, principally in cases where little known on the AAS that will be designed. Case studies using the DoE approach as a heuristic optimization method are presented. Additionally, in an attempt to study its effect, in some studies, the number of pallets has been considered as a decision variable. Studies conducted throughout this research indicated that the DoE approach to be an effective methodology. Robust design study is essential to design AAS that are insensitive to uncontrollable factors. Several systems have been investigated and analyses revealed the necessity of robust design study in AAS. Future research areas are suggested
