Continuous improvement at Toyota manufacturing plant: applications of production systems engineering methods

In this paper, we introduce two application studies of Production Systems Engineering (PSE) at a Toyota manufacturing plant in Georgetown, Kentucky, USA. Specifically, we study the engine assembly line and the block production line in powertrain manufacturing. By applying PSE methods, analytical models have been developed and validated using the data collected on the factory floor. It is shown that the models provide accurate estimates of line throughput compared with that observed in actual production. Using these models, we then develop methods for continuous improvement. In the engine assembly line, we identify the system bottlenecks, which are the machines impeding system throughput in the strongest manner, and improve line performance through bottleneck elimination. In the block production line, we evaluate the lean buffers, which have the smallest buffer capacity necessary and sufficient to achieve the desired line throughput. The results of these studies have been successfully implemented on the factory floor. It is shown that the line throughput has been increased significantly in the engine assembly line, and the buffer capacity has been reduced substantially in the block line.