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Lean Pulls the Need for a Six Sigma Approach to Continuous Improvement

By: Kennith Scott, Training SpecialistKen Scott

Whenever continuous improvement is discussed, it is usually a matter of moments before the terms “Lean” and “Six Sigma” are mentioned. My experience at General Electric indicates we may even witness the development of lean thinkers verse six sigma thinkers over the course of the conversation.

As a strong proponent of both systems, I was often confused to hear one group degrade the other group’s efforts. When I look at the definitions of the lean and six sigma philosophies, I see the customer as a common thread.

Lean: Add value as defined by the customer with the least amount of resources.

Six Sigma: Focus on continuous improvement by understanding customer needs, analyzing business processes, and instituting proper measurement methods.

Knowing both systems have the common goal of meeting the needs of the customer, the question changes from “Which of the two is a better process?” to “How do these two systems integrate?” I see six sigma as a necessary tool for all organizations on the lean journey, but this tool requires process stability in order to do the deep statistical analysis that is the source of its problem-solving power.

Lean has the necessary tools to create the process stability required to efficiently complete a six sigma project. Once lean creates stability, six sigma has the tools to enable the data-driven decisions necessary to overcome the “obstacles” to more sophisticated lean principles such as cellular and single piece flow. In short, lean should pull the need for six sigma analysis.

Let’s look at a hypothetical example of how this might look. ABC Company has been on a lean journey for several years, in which time they have achieved substantial gains through 5S, Visual Management, and efforts to reduced lead time based on Value Stream Mapping.

One value stream contains a widget molding process that is now having trouble meeting the growing demand of the business. The team has increased throughput by eliminating the wasted time associated with non-value added work and are now challenged with shortening the cycle time of a machine that “has always run good the way it is.” The molding process is complicated with several interdependent variables. Purchasing new equipment is beyond ABC Company’s financial capability.

Six sigma is not only a philosophy, it is a problem-solving process comprised of five key steps: Define, Measure, Analyze, Improve and Control. ABC Company can use the DMAIC method to optimize the molding process to both reduced cycle time and to increase quality to a six sigma level (six sigma is <3.4 defects per one million opportunities). They can further increase the capacity of the process to meet the immediate growth in demand without capital investment.

Let’s look at the each of the five DMAIC steps and discuss how ABC Company’s lean efforts will benefit their six sigma efforts.

Define: Communicates the importance and scope of the project and the team members needed to improve the process.

ABC Company has clearly mapped value streams and clearly identified obstacles to their next target condition. Most of the Define content is a copy and paste activity. The homework of why they need to do a six sigma project and its importance to the business is already done.

Measure: Evaluates the ability to measure objectives of the project and evaluates the current state capability of the process.

Through workplace organization and standard work, ABC Company has already established the process stability required to measure the process. They also have standards in place for how to measure allowing them to show capability without efforts toward improving the measurement process.

Analyze: Identifies and verifies all the sources of variation in the process that determines the process output.

ABC Company doesn't know it but they have greatly reduced the time required to complete a deep analysis of all sources of variation. Their lean efforts toward standardization have already eliminated several sources.

Improve: Test, trial, and implement solutions that will improve the process capability.

ABC’s lean culture of creating standards and striving to meet those standards will allow them to complete their test runs and implement solutions with far less errors and in far less time.

Control: Sustain the gains!

ABC Company is a lean-minded organization; they already desire a way to sustain.

Six sigma is a process that requires specialized training, significant resources, and a laser focus on the right project to be truly successful. When it is pulled in at the right time, it can take us through those obstacles that initially appear beyond our capability to overcome. Is your lean journey leading you into a need for Six Sigma? Training Services is offering a six sigma open enrollment starting Tuesday March 24, 2015. Additional information may be obtained by calling me at (231) 995-2212. I hope to see you there.

Kennith Scott
Training Specialist
Northwestern Michigan College
1701 East Front Street, Traverse City, MI 49686
( 231) 995-2212

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