In quality we are obsessed by efficiency, by doing things as good (in the broad sense of the word) as possible. In Lean the first question we ask is if what we do is worth while doing. Optimising an activity that adds no value for the customer can hardly be seen as a really important improvement.

Lean Concepts

• The best known Lean concept is "eliminate waste" (“Muda”), which means we need to define what steps in our process add value or not to the customer. The process is the entire supply chain, from supplier to customer and it is the customer who decides what the value is.
  
  
• Lean is more then just eliminating “Muda”. The term “Mura” indicates the occurrence of problems by excessive variations in the process and is a direct link between Lean and Six Sigma resulting in Lean Six Sigma.
  
  
• “Muri” refers to frustration as a cause of problems and is a good concept to detect problems in the service industry and to get personnel commitment.
  
  
• The customer only pays for products that he has ordered and received. Our planning must be order based and orders have to be pulled through the supply chain. As order quantities are reduced we need a flexible production system.
  
  
• There must be a continuous flow of products with minimal stock between process steps. The ideal is lot size one with minimum throughput time.
  
  
• The slowest step in the process will determine the overall speed. To increase speed we need to improve the bottlenecks and do something about them. This is the basis for the “Theory Of Constraints (TOC)” of Goldratt and fits perfectly in Lean.
  
  

Lean tools

The tools used in Lean are simple and directed at observing the reality. To be successful, they require a lot of discipline!

• Value Stream Mapping is a type of flowcharting, using special symbols to indicate what is happening in the process and to highlight non value adding activities. It shows an overview of the flow of products through production and gives a clear insight into potential savings.
  
  
• Single Minute Exchange of Die (SMED) aims at minimizing setup time for a machine or system. It increases flexibility and allows the production of small series without a big drop in productivity. 
  
  
• Poka-Yoke is a Japanese term that means making a system error-proof. This can be done by adjusting product or process design. Poka-Yoke is the control method of the future.
  
  
• Kanban is a planning method that supports order driven planning in a very simple way. We only produce what is needed in the quantities needed. This can be done by planning cards, but the packing itself can be also be the kanban token.
  
  
• Total Productive Maintenance (TPM) is dealt with in a separate chapter with extra attention for Condition Management.