Six-Sigma

Six Sigma is a process to improve performance. There are thick books on the topic and entire courses devoted to training someone on the topic so what follows is just a brief synopsis of the technique. The name derives from the Greek letter a , or sigma, which is used as an abbreviation for standard deviation. The standard deviation is the square root of the variance. If the data fits a bell-shaped normal distribution curve, 68% of the numbers will fall within one standard deviation of the mean, 95% within two standard deviations, and 99.7% within three standard deviations. Six Sigma has a focus on decreasing the number of defects. A defect is anything out of specification. 

If we think about each opportunity for a defect to occur, we can measure defects per opportunity and not per unit. In the case of the steel rods, we would have a defect rate of one per 1,000 opportunities or 1,000 defects 

Implementation of Six Sigma involves people throughout the organization and the training of many people. Sometimes their roles are given names such as Black Belts or Green Belts , based upon the amount of training 

As the DMAIC process is followed, it is important that a phase be completed before the next phase commences. It does not make sense to embark upon the measurement phase prior to having a clear definition of what is important. This can be done informally or by a formal gate mechanism where the project cannot proceed to the next phase until it undergoes a gate review. 

These techniques can be used throughout an organization or in smaller pieces such as a particular chemical process. Eor example Lean Six Sigma has been used to improve a selenium analysis [6] and showed the importance of improving the digestion of the sample. 

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The minimum level of capability set by Motorola in their Six Sigma quality philosophy is Cp = 2 which equates to 0.002ppm failures. Some companies set a... 

Battin, L. 1988 Six Sigma Process by Design - Design and Dimensions. Group Mechanical Technology, 1(1), Government Electronics Group, Motorola Inc., Scottsdale, Arizona. 

Harry, M. and Stewart, R. 1988 Six Sigma Mechanical Design Tolerancing. Schaumberg, Illinois Motorola University Press. 

In petrochemical and bulk commodity chemical manufacture, real-time process control has been a fact of life for many years. There is considerable understanding of processes and control of process parameters is usually maintained within tight specifications to ensure statistical process control to within six sigma, or the occurrence of one defect in a million. This has been enabled through the use of real-time analytical capability that works with programmable logic circuits to make small changes to various process inputs and physical parameters as required. 

Metrics for this might include number of excursions from statistical process control, but one very useful metric for controllability is process capability, or more accurately, process capability indices. Process capability compares the output of an in-control process to the specification limits by using capability indices. The comparison is made by forming the ratio of the spread between the process specifications (the specification width ) to the spread of the process values. In a six-sigma environment, this is measured by six standard deviation units for the process (the process width ). A process under control is one where almost all the measurements fall inside the specification limits. The general formula for process capability index is ... 

Improvement teams, Six-Sigma, 21 174 Impurities. See also Contaminants Metal ion impurities Purification caustic soda in removing, 22 832 in limestone, 15 33, 34t, 40 in magnesium, 15 342-343 in manganese ore, 15 542—545 in metal, 16 130 in MOCVD growth, 22 157 removal in vinyl chloride manufacture, 25 641, 642... 

In addition to the standard approaches of knowledge transfer the use of lean six sigma approaches, for instance value stream approaches and process flow charts can facilitate better understanding by the receiving site of both the technical facets of the method and the critical order of the key steps of the method (in an analogous fashion to process understanding assessments). 

Snee, R. D. Lean six sigma and outsourcing - don t outsource a process you don t understand. Contract Pharma, 8(8), October 2006, 4-10. http //www.contractpharma.com/ issues/2006-10/view features/lean-six-sigma-and-outsourcing/. Accessed on 04th September 2012. 

FIGURE i 6 Diagram indicating that the total variance in the analysis results equals the sum of the method variance and the process variance. A capable measurement system has a method variance that is less than 30% of the design width (difference between upper specification level and lower specification level). The production process is considered to be under full control when the average assay value is centered at Six Sigma values away from the lower and upper specification levels. 

This previous definition had been broadened after the FDA s issue of the PAT guidance document to encompass aU factors influencing the quality and efficiency of a chemical or pharmaceutical manufacturing process. Driven by developments in Six-Sigma and operational excellence programs an extended definition included such items as ... 

ICH Q8 also discusses the concept of QbD, which has its roots in the early quality and Six Sigma for manufacturing work of Juran and colleagues. ... 

Resumes For Dummies 0-7645-5471-9 "Selling For Dummies 0-7645-5363-1 "Six Sigma For Dummies 0-7645-6798-5... 

A quality management system s process should follow a standard Six Sigma process improvement life cycle that includes the following steps define (process and metrics), measure and control (identify problems and issues), analyze (analyze problems and issues), and improve (implement) circling back to measure and control [11]. An example of a process improvement life cycle can be seen in Figure 9. 

George, M. (2004), Lean Six Sigma Pocket Tool Book, McGraw-Hill Professional, New York, p. 4. 

Marash, S. A., Berman, P., and Flynn, M. (2004), Fusion Management Harnessing the Power of Six Sigma, Lean, ISO 9001 2000, Malcom Baldridge, TQM and Other Quality Breakthroughs of the Past Century, QSU Pub., Fairfax, VA. 

Nash, R. A., Practicality of Achieving Six Sigma or Zero-Defects in Pharmaceutical Systems, Pharmaceutical Formulation Quality, Oct./Nov. 2001. 

This is a commonsense argument for change control, not only because the product we produce is pharmaceutical, but also because change control applies to other industries as well, including airlines, automotive, and electronics. As a matter of fact, many industries have this requirement, and where they do not, they are looking for ways to implement it. The ISO series and Six Sigma are two examples of current quality and business improvement initiatives, which both improve the processes involved and implement change control to keep the process consistent. 

Barney, M. 8c McCarty, T., The New Six Sigma A Leader s Guide to Achieving Rapid Business Improvement and Sustainable Results Prentice-Hall, PTR Indianapolis, IN, 2003. 

There is a wide range of tools in the Six-Sigma toolbox, used during the define phase of a Six-Sigma project, which can be applied effectively for problem definition. Such tools... 

Many people are familiar with work processes, including Bottom Line Innovation, TRIZ, and the various Six Sigma elements. These standardized techniques for work processes have gained a broader use throughout the chemical industry. 

Many CQI models exist. Examples of specific models include the plan, do, check, and act (PDCA) model and the find, organize, clarify, understand, select, plan, do, check, and act (FOCUS-PDCA) model and six sigma (Lazarus and Butler, 2001 Lazarus and Stamps, 2002). Most models include elements that reflect the following core concepts (1) plan, (2) design, (3) measure, (4) assess, and (5) improve (Coe, 1998a). 

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