Lean manufacturing seeks to eliminate waste. According to "Essential of Lean Six Sigma" by Salman Taghizadega, the primary forms of waste lean manufacturing seeks to reduce or get rid of are: overproduction, delays, waiting, transportation or material movement, work in process, excess inventory, wasted motion, defects and errors or mistakes. Mr. Taghizadega also considers underutilized talent a waste, though this was not considered a form of waste by the original Toyota lean manufacturing principles.
The lowest level of lean manufacturing skill is the white belt. These individuals have been taught a basic overview of the concepts of lean manufacturing. The next level of lean manufacturing skill is the yellow belt. These employees are taught how to identify waste and recommend ideas about how to reduce it. They may work as subject matter experts or shop floor liaisons for lean manufacturing projects.
The next level of lean manufacturing skill is the green belt. The green belt has intermediate training about lean manufacturing concepts. Lean manufacturing green belts receive this training in addition to their on-the-job training. They have also been taught how to manage small lean manufacturing projects. Green belts can lead small shop floor lean manufacturing initiatives. They are also the team members for projects led by lean manufacturing black belts. Green belts typically earn their certifications by completing a lean manufacturing project under the supervision of a black belt.
Lean manufacturing black belts are leaders of lean manufacturing projects. Master black belts of lean manufacturing are the highest level of skill in this area. They train all lower skill levels of lean manufacturing, including new black belts. Master black belts are also responsible for very large projects involving multiple black belts.