Toyota Production System in a nutshell
What is Lean Manufacturing?
Toyota’s Lean System – AKA:
- Lean Manufacturing
- Toyota Production System or TPS
- Toyota Manufacturing System
- Just In Time (JIT)
- Flexible Mass Production
- Continuous Improvement
- value – anything a customer is willing to pay for
- waste (muda) – any activity in the process of production that does not add value
Value is always defined by the customer. Not the factory’s shareholders, not the research and development division, but the guy who writes the check.
An engineer might think that Beethoven’s Ode to Joy sounding each time the car’s doors are unlocked is a must, but if most drivers are fine with the good old chirp or find the feature annoying, none of the engineering, material or labor that went into the project added any value to the car and they were therefore nothing more than waste.
Value is anything that a customer is willing to pay for.
Any activity (motion) that is unproductive or does not add to the value of the product is waste. Toyota managers use the Japanese word “muda” which means “waste” or “uselessness”.
The seven kinds of waste are:
- unnecessary transportation
There are other kinds of muda that are not included in the classic 7. For example, many workers’ skills and talents are not used, thus wasting valuable resource and decreasing their overall satisfaction (which in itself affects the workers’ motivation and energy and so the efficiency).
Lean Philosophy | basic values
Conventional firms adapt what at Toyota is called Kaikaku, or “radical improvement”. Occasionally, a new expensive machine is purchased or new building added to the factory, etc.
While periodic large investments are appropriate, lean management focuses on continuous improvement (“Kaizen” means “good change”). No question frequent, even daily small improvements are more beneficial than rare, radical upgrades.
The natural outcome of the correct understanding of the Lean Philosophy is constant effort to reduce waste. The goal is to completely eliminate every kind of muda from the processes.
Interesting fact: as James P. Womack and Daniel T. Jones point out in their “Lean Thinking”, the time that takes from the day aluminum for making a Coke can is dug out to the moment we purchase it in a store takes about 320 days. But making a can of Coke actually takes only 3 hours. This includes digging (20 min.), oxidation (30 min.) and smelting (2 hours) of aluminum. The rest (more than 99%!) is waiting, transportation, etc. Imagine how low the costs of making Coke would be if all waste was eliminated!
Proper muda reduction will always result in increased efficiency.
Reduction of waste decreases costs.
Respect for the Workers
Lean management respects the workers and all aspects of their natural capacity. Monotonousness, ignoring human needs such as acquiring new skills, using creativity, having a sense of accomplishment, positive pride in their own creation etc. reduces the workers’ overall satisfaction. And have I mentioned the word “waste”?
Flexibility is an important value. Both the workers and the management need to be flexible in order to deal with constant change. Machinery must be adjusted so that the time taken to change the tooling is reduced to a minimum. There have been cases when lean engineers have managed to reduced the time from hours to seconds (SMED).
Smoothness of Work
A big part of muda reduction efforts deal with improvement of the flow of production.
The work is smooth when value is constantly added to the product. Ideally, from the moment material is delivered, the process of turning it into the final product begins and continues without any interruptions.
Automation with a human touch
The term in Japanese is “Jidoka”. It is often translated as “Autonomation” or “intelligent automation”. Basically, any defect or abnormal situation in the process of production causes the whole production line to stop. This way any release of defective products are prevented and attention is focused on correcting the source of the problem.
Perfect First-Time Quality
Correct employment of autonomation and simple poka-yoke devices should theoretically eliminate the potential of defective parts being produced. Consequently no quality control is necessary.
Long Term Relationship with Suppliers
Good relationships with suppliers and taking steps to improve their processing eliminates costly excess inventory and can enhance the quality of supplied parts.