Lean Six Sigma Key Terms

4M Affinity Diagram: 4M stands for Man, Method, Machine, and Material. The thought behind 4M is that every problem we encounter will fall into one of these categories. 4M begins as a brainstorming session with you and your team. After observing the process, each team member contributes their thoughts on possible causes. The goal is to narrow down the possible causes and identify the critical x’s, or the most critical causes that you will focus on improving.

5S: One of the foundational improvement principles used in Lean is called 5S. 5S received its name from the five Japanese words: Seiri, Seiton, Seiso, Seiketsu, and Shitsuke. Ironically, they translate into English words that also start with the letter S:

• Sort – or remove all unnecessary items
• Straighten – A place for everything and everything in its place
• Shine or scrub – maintain superb cleanliness of all things so you can quickly identify a problem
• Standardize or Systematize – build a mechanism to standardize the previous three steps
• Sustain – Build a culture of discipline and look for continuous improvement opportunities

5S should be implemented in sequence, and will result in lower safety incidents, improved quality, and increased productivity.

5 Whys: Asking Why five times is often useful in determining the root cause of a specific problem. For example, if we ask 'Why' did the employee slip on the floor? There was oil on the floor next to the machine. 'Why' was there oil on the floor in front of the machine? Because a seal deteriorated. 'Why' did the seal deteriorate?????The seal was not replaced according to specifications. 'Why' wasn't the seal replaced according to specifications? The technician did not know that the seal needed replacement. 'Why' didn't the technician know that it was necessary to replace the seal? Replacing the seal was not recording in the Preventative Maintenance or PM schedule. If we update the PM schedule to change out the seal according to specifications, we prevent the abnormality from happening in the future.

Andon: A Japanese term meaning lantern, it refers to a visual management system using signals to alert leadership of the status of the process. Color codes vary with the application, but they are commonly classified as:

Green:??????No problems

Yellow:??????The situation requires attention, production flow at risk

Red:???????????PRODUCTION STOPPAGE: IMMEDIATE ASSISTANCE REQUIRED

There are a variety of andons used, including lights, flags, audible signals, such as buzzers and alarms, visual displays, and production boards.

Autonomation: A translation of the Japanese term jidoka, autonomation may be described as automation with a human touch. It refers to implementing technology sensing equipment as a means of preventing defects from occurring by identifying when an error occurs and providing immediate feedback to the employee so they can correct the condition before the defect is created. When implemented, this technique can free the worker to operate multiple pieces of equipment as well as achieve zero quality defects.

Taiichi Ohno explains in his book, The Toyota Production System, "Autonomation means to transfer human intelligence into a machine. At Toyota, this concept is applied to not only the machinery but also to the production line and workers. In other words, if an abnormal situation arises, a worker is required to stop the line. Autonomation prevents the production of defective products, eliminates overproduction, and automatically stops abnormalities on the production line allowing the situation to be investigated."?(Ohno, 1988 )

Continuous Improvement (Kaizen):?A mindset of ongoing incremental activities that focus on improving people, product, service, work environment, and business.?In a true kaizen culture, there is never a point at which things are good enough.

Continuous Flow Processing: Producing goods in a continuous, one-piece-at-a-time production method to eliminate the stagnation of work in and between processing steps, reducing lead-time to meet customer requirements while using minimum resources

Cycle Time: Cycle Time is the period it takes to complete one cycle of an operation, function, job, or task.

DMAIC: The problem-solving methodology used in Six Sigma projects:

• Define
• Measure
• Analyze
• Improve
• Control

Elements of Work: There are three elements of work, with the first and most important being value-added work.?We usually describe this as something a customer is willing to pay for. Non-value added work is work that is necessary, but the customer is not willing to pay for it. The last type of work is technically not work at all, which is why we refer to it as waste. Waste is considered non-value added and unnecessary work. After you are able to identify the three types of work, your organization should focus on adding value to the customer, reducing the amount of non-value-added work, and eliminating waste.

Hoshin Planning: A Japanese term, hoshin refers to a vision, goal, or direction. Hoshin planning is the development of a strategic plan to support the organization's vision or purpose. It is also known as policy deployment, and its main purpose is to unite all levels of the organization, including middle management and front-line employees, with the goals established by senior leadership.

House of Lean: Early practitioners of the Toyota Production System developed the House of Lean as a model to explain the different attributes, strategies, and goals of a lean system.

Jidoka: A Japanese term that may be described as "built-in quality,” Jidoka refers to implementing mechanisms within a system to prevent defects from occurring or detecting them once they occur. Once a defect condition or actual defect is detected, the operator is alerted, and the situation can be corrected before other parts are produced. Jidoka is another way of explaining autonomation, and it incorporates the use of Poka-Yokes, inspections, rapid employee feedback, and andon systems.

Just-in-Time: Just-in-time is an inventory management methodology that only produces precisely when the customer needs, in the required quantity, when it is required. It is also known as a Make-on-Demand strategy.

Taiichi Ohno describes in his book, The Toyota Production System, "With the possibility of acquiring products at the time and in the quantity needed, waste, unevenness, and unreasonableness can be eliminated and efficiency improvement. Toyada Kiichiro, the father of Japanese car manufacturing, originally conceived this idea, which his successors then developed into a production system. The thing to remember is that it is not only 'in time,' but 'just in time.' Just-in-time and Autonomation constitute the two main pillars of the Toyota Production System." (Ohno, 1988 )

Kaizen (Kai – change, Zen – good):?Japanese for 'change for the better' or 'improvement.' It refers to the incremental continuous improvement that increases the effectiveness of an activity to produce more value with less waste.

Kanban: Japanese for signboard or tag, that triggers replenishment or withdrawal of product or materials in a pull system. Kanban regulates the production flow in the value stream. A kanban is often in the form of a card on a container in a production environment, and it has recently been implemented in project management, such as in the software development industry, where specific tasks are written on a Kanban card and progressed through the system until complete.

Muda: Japanese for waste, or, more specifically, the waste in manufacturing. Any activity that consumes resources and adds no value is considered Muda. Muda is categorized into two forms: Type-1 muda is necessary for the process, but non-value-added, and Type-2 muda is both unnecessary and non-value-added.

Plan-Do-Check-Act (PDCA): Also known as the Deming Cycle, PDCA is a short-cycle iterative improvement scheme at the core of the Kaizen process. The four-step process includes

1. Plan: defining the objectives, issues, and potential solutions
2. Do: carrying out the plan in a trial mode
3. Check: verifying the studying trial results
4. Act: fully implementing and standardizing the solution

Poka-Yoke: Japanese for 'mistake-proofing' or error prevention. Mistake-proofing devices are made by designing parts, processes, or procedures in a way that mistakes cannot physically or procedurally be allowed to happen. Shigeo Shingo explains in his book, Zero Quality Control, "Poka-yoke systems involve carrying out 100% inspections and requiring immediate feedback and action when errors or defects occur. This approach solves the problems posed by the old-fashioned belief that 100% of inspections take too much trouble and cost too much." (Shingo, 1986 )

Process Capability: Process Capability refers to a range of KPI's that measure the ability of a process to deliver the customer's requirements. The range between the upper and lower specification limit can be referred to as the Voice of the Customer (VOC), and the total variation in the process can be referred to as the Voice of the Process (VOP). Process capability is the comparison of the VOP to the VOC.

The Capability index, or Cp, measures how well the data fits between the Upper Specification Limit and the Lower Specification Limit.

The Capability Index is calculated by dividing the width of the specification by the range of the Histogram.?

The Centering Capability Index, or Cpk, measures how well the data is centered between the Upper Specification Limit and the Lower Specification Limit.?It is calculated by dividing the distance between the mean and the nearest specification limit by half of the range of the Histogram, or three standard deviations.

In general, a Cp or Cpk index less than one will not meet customer specifications.?A value of 1.33 or higher is considered acceptable, and an index of 2 is excellent, meaning that the process is Six Sigma capable and will have a specification window twice as wide as the process variation.

Scrap: Any work-in-process or finished goods inventory, which cannot be reworked or repaired to meet customer requirements. Typically, scrap is discarded or recycled, accumulating a loss in investment.

Six Sigma: An improvement methodology, Six Sigma was coined by two Motorola executives, Bill Smith, and Dr. Mikel Harry, in the 1980s. Six Sigma utilized the Statistical Quality Control Method to identify variation and abnormalities within the system. The name is derived from the Greek letter sigma, used to define a measure of variability or one standard deviation from a process mean. If a process is Six Sigma capable, it means that the process should have 3.4 DPMO outside the specified engineering limits.

This chart compares standard deviation, DPMO, and quality yield:

Standardized Work: Standardize Work is a defined and documented method to perform an activity, centered around human movement. It should be repeatable and reproducible, with the goal of defining the most efficient way to perform the task. Standardize work should include the process steps characterized by takt time, a set work sequence, and established in-process inventory. Deviation to standardized work constitutes an abnormality, which is an opportunity for improvement.

Takt Time: Takt is a German word for 'beat' or 'rhythm.' Takt time is the pace of production based on the rate of customer consumption. Takt time is defined by dividing the available time to work by the customer demand for that same period.

WASTE: There are eight types of waste using the DOWNTIME acronym:

• Defects
• Overproduction
• Waiting
• Not utilizing Human Potential
• Transportation
• Inventory
• Motion
• Excess Processing

References

Ohno, T. (1988). Toyota Production System: Beyond Large-scale Production. Boca Raton: CRC Press.

Shingo, S. (1986). Zero Quality Control: Source Inspection and the Poka-yoke System. Cambridge: Productivity, Inc.

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