Term LEAN appeared for the first time in 1988 or 1990 depending on sources. But actually LEAN was only new term for JIT philosophy and afterthought it was just simplier and prettier form of JIT. Next book about Toyota and LEAN didn’t appear until 1996.
Focus on LEAN was on flow and waste removing. Many enterprises started to use LEAN. Unfortunately in all this hurry many of the original principle of JIT vanished.
Anyway it looks like LEAN has been way more popular than JIT and has achieved goals even better. We must still remember that JIT has never vanished, its name just changed to LEAN.
LEAN is focused on flow optimization where many of the old production philosphies focus on resource efficiency. Resource-efficient production leads to long cycle time which causes secondary needs. Parts need interim storage and they need more handling which causes expenses from the handling and capital. Also the risk of damage increases in handling.
Interim storages caused by resource-efficient production also weakens error detection. Workstation can produce big batch of faulty products into the storage before next workstation detects the error. In LEAN production errors are detected faster when the waste is kept its minimum and problems causing the errors are detected and located faster and easier.
Flow efficient production minimizes so called secondary need which includes storage for example. Even though in flow optimized production we waste some resources our production is still more cost efficient in its entirety when we don’t have to get extra resources to take care of the secondary needs. Whole philosophy is based on waste minimization and focuses on flow optimization.
Diagram presents the key lessons of LEAN. Methods and practices are in the bottom of the pyramid and they come after we have learned the JIT and Jidoka. JIT was introduced earlier and it stands for flow creation. Jidoka stands for transparent organization where errors and interferes in flow are noticed immediately.
In This is LEAN -book Jidoka is compared to the soccer game where all the players notices other players, judge, goals, field limits and whistle all the time. In order to success players have to be able to recognize all these factors all the time. Bringing this transparent organization into the production facility is not easy. Organizations today are like every players would be playing their own game in their own tents and every time they kick the ball out of their tent they think they did goal. People play their own games in different times unable to see the entirety and doesn’t hear the whistle.
This is why JIT/LEAN factories have boards and lights in visible places. That’s how all the workers can see what is the status of the line. When error is made first one to notice it blows the whistle and the whole factory stops. Just like in soccer. Then workers will find the problem and fix it together
The above pyramid is complemented with tools and functions which are added below the methods. In order to follow the methods we have to have tools and functions. Method determines how the job is done. Principles defines decisions and priorities. At last the value system defines how me must act. Values are the fundamental base which all the operations are based on, they are the state which we aim to.
Most important thing to remember is that JIT/LEAN is not some predetermined practice or tool that you can copy and success. More than anything it is pile of attitudes, philosophy and priorities. Methods and tools lie in the bottom of the pyramid.
Here is the roundup:
- The production enviroment itself is a control. Strategies which reduce setup times, change the product designs to favor manufacturing etc. can mean a lot more than any decisions made on the factory floor.
- Operational details matter strategically. Even the smallest details in production process can be crucial for an competition.
- Controlling WIP is important. Smooth and fast flow of the material is important. Almost all the benefits in JIT comes from the low WIP levels which leads to short cycle time and better quality.
- Flexibility is an asset. JIT is inherently inflexible. It has been developed more flexible with short setup times, workers cross-training, cellular plant layout etc.
- Quality comes first. Competition with Japanese and Americans brought out that production where quality comes first is not only workable but is profitable as well.
- Continual improvement is a condition for survival. Japanese realized that manufacturing is continually changing. Customers demand is changing and technology evolves. Manufacturing must evolve too.