Six Sigma v. Lean

I have always been intrigued with the manufacturing process. Back in my production days, I loved taking a manufacturing problem, breaking it down into its component pieces, discover the variation, fix the variation, then measure to ensure success. When success comes, what a great feeling.


One question that continuly pops up is "What is the difference between Lean and Six Sigma? I hit the old internet and found some great internet battles raging about the differences. I was able to find a few logical discussions and this is what I learned.


Lean Manufacturing

Lean manufacturing focuses on eliminating waste. The focus on Lean is breaking down the process to the bare bones. If the activity does not add value, it is waste. The typical methodology for implementing Lean is:

1. Identify the value

2. Determine the value stream

3. Determine the flow

4. Define flow

5. Improve process.



Six Sigma

Six Sigma focuses on eliminating problems with the manufactured product. The primary tool sets of Six Sigma is math and statistics. Six Sigma typically uses the DMAIC method. DMAIC is:

1. Define high level goals and the current process.

2. Measure key aspects of the current process and collect relevant data.

3. Analyze the data to verify the cause and effect relationships. Determine what the relationships are and attempt to ensure all factors have been considered.

4. Improve or optimize the the process based upon data analysis.

5. Control to ensure all deviations from target are corrected before they result in defects.

My Take:

If you are in the metalcasting business, you will want to incorporate some of each of these strategies into your plant. By reducing waste, you will keep the costs down, for both yourself and for you customers. Similarly, by reducing defects you will have satisifed customers. You will also reduce rework and scrap, both of which directly affect your bottom-line.

Well, I am on vacation for the next week or so. Have a good one.