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Sep 23, 2010

Six Sigma vs Lean Manufacturing

Six Sigma and Lean Manufacturing are separate process that help organizations eliminate defects or waste in the business process. Both these process are helping a business save huge costs that come about due to waste generated in the process. Although Six Sigma and Lean-Manufacturing have a similar purpose, there is a thin line of difference between them. While Six Sigma focuses on reducing variation, Lean Manufacturing focuses on improving productivity:

Six Sigma - Six Sigma methodology is aimed at eliminating or reducing defects in a business process by utilizing fundamental process knowledge. Six Sigma methodology integrates principles related to business, statistics and engineering to achieve desirable business results. The principles of Six Sigma can be applied in almost every field such as Production, Sales, Marketing, Design, Administration and Service. When applied skilfully, Six Sigma can offer significant benefits to a business. The principles of Six Sigma are designed to reduce wastes, reduce costs by at least 50%. Through Six Sigma, a company can better understand the customer's requirements and align delivery and performance accordingly. Six Sigma uses internal resources to improve performance.

Lean Manufacturing - Lean Manufacturing works to reduce waste and thereby streamline business processes. It strives to achieve this by reducing inventory and floor space requirements in a manufacturing process. Lean Manufacturing also ensures proper delivery systems and ensures a proper work layout so as to increase flexibility. Besides, lean manufacturing also requires a replacement of old factory tools with latest ones. By taking care of all these factors, lean manufacturing gives rise to a robust production system.

Since every defect in a manufacturing process leads to delays in production, increases in costs, lessening productivity and increasing lead times, every organization desires an error free production process along with high levels of productivity. To successfully achieve this, organizations will need to implement principles of Six Sigma as well as Lean Manufacturing. Hence, a combination of the two give rise to a new concept called Lean Six Sigma. Some of the tools used by Lean Six Sigma today are:

5 Whys
Affinity Diagram,
Analysis of variance (AN OVA)
Balanced Scorecards
Cause Effect Diagram
Cause and Effect Matrix
Cellular Manufacturing
Control Charts
Design of Experiment (DOE)
Failure Mode Effect Analysis (FM EA)
Force-field Analysis
Hypothesis Testing {t-test (two-sided),Chi-Square test }
Kan ban

Although lean Six Sigma combines the principles of both disciplines, It is better to use Ono's discretion depending on the problems being faced. For instance, if the problem is more related to wastes or less productivity, it is better to implement more principles of lean manufacturing. However, if the problem is more related to product variation, then Six sigma must be applied.