The philosophy Behind Six Sigma:

Six Sigma has these four points, which it emphasizes on.

  1. Know what is important to the customer. Whatever improvement project you are doing make sure that it is important to your external customer. Any improvement project should be aligned to the customer needs, expectation, or satisfaction. (critical to quality)
  2. Reduce defects. Six Sigma emphasizes on reducing the defects to the level of 3.4 defects per million opportunities (DPMO).
  3. Target at the mean. Six Sigma looks to achieve the center of the tolerance, rather than being within tolerance. For example, if you have a dimension as  Six Sigma is targeting on 100mm, rather than between 99mm and 101mm.
  4. Reducing variation. Six Sigma believes in reducing variation. Even though variation is everywhere but it is the enemy of quality, because the quality is related to consistency.

The philosophy behind Lean:

Lean is based on following five principles.

  1. Create value. the first point’s value. specify what creates value from customer’s perspective. this is exactly similar to what we talked in Six Sigma as well. you need to understand what is important to the customer. what is critical to the customer.
  2. Value stream. Identify all the value processes along the process chain. This is where Lean looks at reducing the non-value added processes from the work. Value added activities are those for which client is willing to pay. For example, if you’re doing the inspection at the end of production, the client is not paying for the Client is paying for the product, which you are making. Hence the inspection is a non-value added activity.
  3. Flow. Make sure that the value process flows. This is achieved by reducing inventory in the process and handling one piece at a time. If you have more inventory between the processes, there are good chance that the defects will be hidden in this pile of inventory. However, if you have the one item being processed at the time and there is no inventory in between the processes, any defect which enters the process will be highlighted and will get immediate attention.
  4. Pull. Make only what is needed by the customer don’t create a lot of products and keep that as inventory. This leads to flexibility to quickly from one product to another product. In pull, you are working on what the customer is demanding. The opposite of this is the push, where produce first and then your marketing or the sales department pushes to sell these.
  5. Perfection. And this is exactly similar to Six Sigma, where you are striving for perfection by continuously improving. You perfect your processes you removed defects from your work processes.