Glossary of Six Sigma Terms: Letters S – U

S

• Short Run SPC.

  When used in batch production, Short Run SPC measures deviation from the standard product size. You should use it when the runs for a particular item are too short compared to the standard size. Six Sigma Black Belts and Green Belts use Statistical Process Control on process improvement projects. You would use SRSPC if you wanted to analyze data in process improvement projects. Imagine you have a range of bars all at differing diameters. Furthermore, if your process involves machining these bars, then the control charts will monitor each deviation from your target diameter. There are difficulties with this process, as the amount of variation tends to vary with each part. To tackle this problem, we recommend using a ZmR chart. This will help to divide your target value using the standard deviation.

• Statistical Process Control.

  Known alternatively as SPC, statistical process control uses a statistical approach to monitor your processes. Moreover, you should also use statistical process control to analyze and monitor any form of production process, along with business-related and transactional processes. Variation affects all process varieties, and you can use SPC for the following actions:

• To make certain a process’s stability, including confirming that process output characteristics conform to your normal Your parameters in these circumstances will usually be constant over long periods of time and SPC is great at recognizing them.

• To monitor processes via statistical methods, identifying any special causes that could indicate changes in parameters. Your main tools here would be standard control charts as well as process capability studies

• SWOT Analysis.

  Strengths, Weaknesses, Opportunities, Threats, make up the acronym SWOT analysis. It is great for digging into the driving factors behind processes. Like PEST and Porter’s Five Forces, SWOT is a highly effective strategic-level analysis type to help you understand your data. Each letter interrogates different aspects of processes but also general business elements. Strength looks at the strongest internal facets of a business, including actions and services where you excel above your competitors. Weaknesses focuses on the weakest internal facets of a business. This may also include processes and activities that the business struggles to overcome, such as poor image, obsolete equipment, or inadequate location.

  Opportunities concerns, as the name implies, any outside opportunities available to the business, such as availability of new markets and enterprises. Finally, Threats identifies any external threats such as legislation, any terrestrial or overseas competition that could affect the company. Therefore, the more you understand about your business’s place in its surrounding environment, the greater your chances of success. Black Belts, Green Belts, or Yellow Belts may wish to use SWOT analysis in their work.

T

• Taguchi, Genichi.

  Genichi Taguchi was a Japanese engineer and statistician, famed for his invention of the Robust Design concept. Taguchi’s work also aimed to find solutions that would minimize variation in design and production. He developed a range of different tools for this purpose, including:

• Loss Function, which you can use to calculate the cost of variation.

• Design of experiments, which he devised, along with orthogonal arrays, outer arrays, and linear graphs, to analyze variation.

• Signal to Noise Ratio is a method of optimizing processes. Taguchi intended it to be a core component of Taguchi experimental design, with links to the Taguchi Loss Function. Taguchi intended to use Signal to Noise Ratio to maximize your target performance. As with all of his work, he believed a robust approach was the best way forward. Equally, robust approaches allow you to identify processes that will deliver consistently good results. As opposed to ones that are only theoretically better and deliver worse results on average.

• Robust Design. This was one of Taguchi’s main contributions to Six Sigma, though he also devised similar engineering products and processes in an attempt to minimize variation. He called for a three-step process that involved first designing your system, then your parameters, and then your tolerance.

Dr. Genichi Taguchi was Executive Director of the American Supplier Institute for several years before his death in 2012. Six Sigma practitioners, namely Black Belts and Green Belts, utilize Taguchi’s ideas in process improvement work.

• Takt Time.

  Lean practitioners measure Takt Time in Lean Production systems. Takt Time is the length of time between production of two consecutive items. Customer demand is also important here as you must achieve adequate Takt Time to satisfy customers. Imagine that customer demand constitutes, on a daily basis, around 50 items. That would mean 500 minutes of production time would need to take place for your Takt Time to be 10 minutes. Simple multiplication allows you to calculate Takt Time. Originating in the Just-In-Time production system, we usually refer to Takt Time as the heartbeat of the system. Moreover, this comes from the idea that you should set a pace for production that produces one item per every ten minutes. Other systems prefer to work in periodic batches, but Takt Time is often far more effective.

• TRIZ. 

  An acronym for Theory of Inventive Problem Solving, TRIZ originated in the Soviet Union. TRIZ emphasizes the idea that solutions to problems tend to repeat across several, if not all, industries. Therefore, solutions to these problems, when they arise, could potentially have already been solved in a different application. As such, TRIZ aims to develop a systematic method of invention, which involves reducing it to a set of principles by which to work. That way, it becomes easier to formulate solutions. Six Sigma practitioners of all Belt colors may use TRIZ in Design for Six Sigma (DFSS) to design or redesign a process.

U

• Unintended Consequences.

  It is difficult to predict future circumstances in Six Sigma, and there will always be unintended consequences for which to watch out. These are situations where an action results in consequences you were not expecting or for which you did not intend. Unintended consequences appear not just in Six Sigma but also in Lean. While they may be both foreseen and unforeseen, they will always be logical results from the action. In Six Sigma and Design for Six Sigma, we can divide unintended consequences into three categories. Unexpected outcomes that are positive. Potential causes of problems and corresponding loss of quality. Negative effects and results that are completely contrary to what you intended.