Simulation study of the effects of intercell movements on the performance of flow shop cellular manufacturing systems

A computer simulation study has been conducted to investigate conditions in which intercell movements in cellular manufacturing systems improve the overall performance of the systems. A hypothetical flowshop cellular manufacturing system that consists of two alternative cells each with four machines was used in the simulation. Due to changes in market driven factors such as product demand and product mix, load imbalances between cells may occur. Load imbalance may also occur as the result of internal changes in the company, such as changes in manufacturing technology, product design, materials used in the process, and the skill of the workers.;When imbalances occur, not only is the machine utilization low, but jobs may also fall behind schedule. Rearranging facilities to counter the changes is not only costly but may become an endless and futile endeavor because in batch industry changes always occur. The study shows that intercell movements can solve the lateness and utilization problems. The study proposes a procedure that can improve the performance of the system. The systems that will benefit most from intercell movements are those which utilize general purpose machines.;The implication of this finding is that a cellular manufacturing system which consists of cells that are substitutes has the most benefit from the intercell movements.;Historically, Group Technology (GT) manufacturing systems evolved from jobshop manufacturing systems. The operational benefits of GT system can be achieved if each part family is completely processed within a manufacturing cell and the manufacturing process is set up by organizing the equipment in a flow-line manner within cells (pure GT system). In practical situations, however, it may not always be possible to meet both of the above conditions. Deviations from pure GT systems, such as GT hybrid shops have evolved from an attempt to improve the performance of GT systems. It has been shown that, in a hybrid system, where controlled interaction between the cells (i.e., intercell flow) is allowed, significant improvement in the overall system performance is possible.;Cellular manufacturing recognizes that small to medium sized batches of large variety of part types can be produced in a flow-line manner. A flow-line production system is characterized by product layout and the use of special purpose machines. A job shop on the other hand, is characterized by functional layout and the use of general purpose machines. To achieve the most benefits of GT system there is a tendency to utilize special purpose machines in the cells. The results of this study suggest the opposite, i.e., cellular manufacturing systems should be designed to have product layout but using general purpose machines. Designing a cellular manufacturing this way and allowing intercell movements between cells improves the overall performance of the system.