Flow

Imagine you’re in an engineering plant. Raw materials come into the plant, where they are painted, assembled, repainted, have a QA inspection, are loaded into trucks, and hauled away. The workers can offload 1,000 widgets per hour into the staging area; initial painting is 750 widgets per hour, assembly is 500, repainting is 750, and the team can inspect 1,000 widgets per hour. What is the net output of the factory?

It doesn’t take a wizard to figure out that the factory will produce an output of 500 widgets per hour. Performance improvements regarding the repainting or inspection team are a total waste of time. It would be better if those teams decreased staff, moving them to help with the assembly process. Eli Goldratt’s theory of constraints provides some ideas to help us improve performance in such a factory. For example, we want to keep the assembly team working all the time; we might build up a little parts inventory in front of them in case they...