How do I Compare the Six Sigma Project Plan to the Lean Project Plan?

Six Sigma and Lean project plans share several similarities.

Six Sigma projects focus on using the DMAIC critical thinking methodology and analysis to measure defect opportunities. DMAIC stands for Define, Measure, Analyze, Improve, Control. Lean projects use PDCA, and focus on visualization and timing techniques to improve flow of information and products. PDCA is an acronym for Plan, Do, Check, Act.



Both project plans result in identifying process improvements that affect quality, schedule and costs. Six Sigma and Lean use common tools such as performing root-cause analysis and applying mistake-proofing procedures. Some industry experts say the two are under the same umbrella of continuous improvements; other experts consider them to be similar, but not the same.

Instructions

Six Sigma highlights

1. Use the DMAIC critical thinking model when deploying Six Sigma projects. The methodology was created by Motorola in 1981 to reduce quality defects, improve schedules and reduce costs by looking at opportunities for failure.

2. Measure defects with the Six Sigma philosophy by using CTQ (Critical to Quality), CTS (Critical to Schedule) and CTC (Critical to Cost) opportunities. Use SPC (Statistical Processing Controls), by establishing upper and lower control limits based upon normal distribution. Determine sigma or standard deviation using X-Bar formulas to calculate. Other tools used are DOE (Design of Experiments), FMEA (Failure Mode and Effects Analysis), cause and effect analysis, Continuous Gage R&R (Repeatability and Reproducibility), and capability analysis in the form of trend (Histograms) and control charts.

   Engineers, statisticians and those holding a bachelor of science degree are most likely familiar with such basic statistics. If you're interested in learning more, enroll in a basic statistics class. If you're pursuing a Six Sigma degree, examine the Wisconsin School of Business certification offered to Green Belts.

3. Focus on removing quality defects to improve Six Sigma projects. Provide specialized training on how to do this and give yellow, green and black belts to champions who will help transform your organization. Target high-value, high-impact projects; the Six Sigma process is formalized and needs to show return on investments. Obtain management authorization to begin and report progress through project reviews. Reduce costs, and improve schedule and quality.

4. Define the current metrics and the desired metrics. Measure differences, analyzing processes to find out why defects are happening. Improve the process and control defects through mistake proofing. Use control charts and measure inputs. Develop data collection plans as part of the define and improve stages. Institute quality inspections as part of the processing steps, rather than at the end of the process.

Lean highlights

1. Use the PDCA critical-thinking model when applying Lean concepts. Look for ways to make process flow continuously as Henry Ford did in 1913, when he used flow in manufacturing the Model-T in Highland Park, Michigan. Produce sub-assembly inventory parts that will be ready on the main assembly line. Use go/no-go gauges to stop work in progress when quality defects are found. Group machines together sequentially and chronologically to improve production times.

   Later, quality engineer Edward W. Deming, Ph.D., was asked to share his work with Toyota, which wanted to change the perception of its quality in America. Deming applied psychology to quality and developed 14 points that Kiichiro Toyoda, Taiichi Ohno and others began applying to management. Deming believed that when something went wrong, 85 percent of the time or more it was the process and not the people.

   The leaders of Toyota came to the U.S. and assessed the grocery industry. They took back the supermarket concept of having product on the shelves when customers wanted it, and developed the Toyota Production System.

2. Use tools such as value stream mapping, standard work, Kanbans (a visual system that tells you how many to produce) and Kaizen (process improvements). Teach employees about the seven deadly wastes, known as Muda. By eradicating Muda, you'll reduce nonvalue activities when planning a Lean project. Direct employees to take a Gemba walk, or go to the source of the problem.

   Use Takt, a lean word derived from the German word, Taktzeit, that translates to "cycle timing." Establish a production rhythm. Measure available time for work in minutes and divide it by customer demand rate. For example, an eight-hour shift might be equal to 480 minutes, but the available time shrinks to 400 minutes when you subtract breaks, lunch and daily shift management meetings. Divide this by required customer units, for example 400 units, and the Takt time or shop flow should equal one minute for each piece or every minute a piece must be produced to meet customer demand. Use this as a thermometer to measure health of production flow.

   "Level load" work stations evenly, proportioning work loads to minimize waste and chaos. Adopt Just In Time (JIT) thinking, working diligently with suppliers to minimize inventory costs. Institute cross training and mentoring to maximize use of human intellect.

3. Focus on understanding what the customer wants and giving it to him by examining value streams, flow, waste and continuing to perfect the process until it meets demand. Expect everyone in the organization to work toward improving processes. Implement Lean projects quickly and empower employees to improve processes without needing management approval. Focus not just on quality, schedule or costs, but also on health, wellness and safety.

4. Start with defining the current state and then develop a future state through value stream mapping, reviewing standard work, and brainstorming on ideas and ways to make the process better. Count the number of processing steps, the number of physical steps and the time that inventory sits in queue to target bottlenecks. Review the Best of the Best (BOB) and Worst of the Worst (WOW) to understand the source of variation. Use histograms to depict trends. Set goals and measure progress.

Tips & Warnings

• Whether you are using Lean or Six Sigma, or a combination of the two, the end result should be a process that's faster, easier, less costly and more efficient. Don't recreate the wheel by trying to come up with your own critical thinking method. Apply one method and work to understand and remove variation.

• Inexperienced Lean or Six Sigma practitioners may get stuck working on the symptoms (missed deliveries) rather than the true root cause of a problem (incapable machines or workers). Always ask yourself before implementing improvements if this is going to fix the problem and eliminate it. If you can't eliminate the problem, at least contain it in a controlled approach. If process improvements will not eliminate or at least limit the possibility of errors, continue searching for true root cause before working the project.

References

• Lean Organization: History
• ASQ: Comparing Lean, Six Sigma and Theory of Constraints
• Lean Manufacturing Concepts: TAKT time
• Superfactory: Gemba
• CAMO: Design of Experiment

Resources

• Sprickstegall: Three standard tools
• Wisconsin Education: Six Sigma