What role does standardized work play in lean manufacturing?

Standardized work is an integral part of lean manufacturing. The premise of standardized work is to reduce variability in processes by documenting and training the best way to perform the process while insuring defect-free, on-time delivery.

First, we have to determine the pace that each incremental step must maintain to enable on-time delivery. Second, we want to determine the best practice sequence of steps in the manufacturing or assembly process. We must eliminate unnecessary steps and then figure out the best sequence which includes minimum travel, motion and waiting. Lastly, we must determine the appropriate inventory. Standardized work is most effectively implemented when done by the team that actually performs the work.

Standardized work is the least-used tool in lean, but arguably the most powerful one. Once standardized work is in place, it becomes the foundation for all improvements. If you think about any problem that occurs in manufacturing, one of three conditions will have caused the problem -- the lack of a standard or the standard isn't followed or the standard needs to be improved. Clearly, the best scenario is having to improve the standard; this means that standardized work has been created, people are trained on it and it is being followed.