六西格玛辞典.doc

六西格玛辞典（英文）Six Sigma Glossary BenchmarkingAn improvement process whereby a company measures its performance against that of best-in-class companies, determines how those companies achieved their performance levels, and uses the information to improve its own performance. Black BeltFull-time Six Sigma project leader who is certified following a four-month training and application program and successful completion of two Six Sigma Projects, the first under the guidance of a Master Black Belt, the second more autonomously. DMAICThe data driven, Six Sigma process improvement strategy involving 5 phases: Define, Measure, Analyze, Improve and Control. CauseThat which produces an effect or brings about change. Cause-And-Effect DiagramA schematic sketch, usually resembling a fishbone, which illustrates the main causes and subcausesleading to an effect (symptom). Also known as Fishbone Diagram. ChampionNormally senior staff of the company who has undergone extensiveSix Sigma training. Champions provide direction, resources and support tothe Six Sigma effort and pprove and review projects. CharacteristicA definable or measurable feature of a process, product or variable. Control ChartA graphical rendition of a characteristics performance across time in relation to its natural limits and central tendency. CorrelationThe determination of the effect of one variable upon another in a dependent situation. CpA widely used capability index for process capability studies. It may range in value from zero to infinity with a larger value indicating a more capable process. Six Sigma represents Cp of 2.0. CpkAn index combining Cp and K (Difference between the process meanand the specification mean) to determine whether the process will produce units withintolerance.Cpkis always less than or equal to Cp. When the process is centered at nominal,Cpkis equal to Cp. Critical To Quality (CTQ)An element of a design or a characteristic of a part that is essential to quality in the eyes of the customer, formerly known as a key quality characteristic (KQC). DataFactual information used as a basis for reasoning, discussion orcalculation; often refers to quantitative information. DefectA failure to meet an imposed requirement on a single quality characteristic or a single instance of nonconformance to the specification. Defects Per Million Opportunities (DPMO)The number of defects counted, divided by the actual number of opportunities to make a defect, then multiplied by one million. A direct measure of sigma level. Defects Per Unit (DPU)The number of defects counted, divided by the number of productsor characteristics produced. A process of counting and reducing defects as an initial step toward Six Sigma quality. DefectiveA unit of product containing one or more defects. Design For Manufacturability (DFM)A concept in which products are designed within the current manufacturing process capability to ensure that engineering requirements are met during production. Design of Experiments (DOE)Statistical experimental designs to economically improve productand process quality. A major tool used during the “Improve Phase”of Six Sigma methodology. DistributionsTendency of large numbers of observations to group themselves around some central value with a certain amount of variation or “scatter”on either side. EffectThat which was produced by a cause. ExperimentA test under defined conditions to determine an unknown effect; to illustrate or verify a known law; to test or establish a hypothesis. Experimental ErrorA test under defined conditions to determine an unknown effect; to illustrate or verify a known law; to test or establish a hypothesis. “Factory”ProcessesFor Six Sigma purposes, defined as design, manufacturing, assembly or test processes which directly impact hardware (see also transaction processes). Fishbone DiagramA schematic sketch, usually resembling a fishbone, which illustrates the main causes and subcauses leading to an effect (symptom). Also known as Cause-And-Effect Diagram. Failure Mode Effects Analysis (FMEA)A process in which each potential failure mode in every sub-item of an item is analyzed to determine its effect on other sub-items and on the required function of the item. “Five Ms”Major sources of variation: manpower, machine, method, materialand measurement. Additionally, “environment”is considered to be a source of variation. Frequency DistributionThe pattern or shape formed by the group of measurements in a distribution. Gage Repeatability & Reproducibility (Gage R&R)A measurement system evaluation to determine equipment variationand appraiser variation. This study is critical to ensure that the collected data is accurate. HistogramVertical display of a population distribution in terms of frequencies; a formal method of plotting a frequency distribution. Independent VariableA controlled variable; a variable whose value is independent of the value of another variable. InteractionWhen the effects of a factor A are not the same at all levels ofanother factor B. Lower Control LimitA horizontal dotted line plotted on a control chart which represents the lower process limit capabilities of a process. Master Black BeltAn expert in quality techniques specially trained to advise leaders, facilitate quality teams and accelerate process improvement. Master Black Belts select, train and mentor Black Belts; develop and implement the Six Sigma deployment plan; and select and ensure completion of Six Sigma projects. NonconformityA condition within a unit which does not conform to some specification, standard, and/or requirement; often referred to as a defect; any given nonconforming unit can have the potential for more than one nonconformity. Normal DistributionA continuous symmetrical density function characterized by a bell-shaped curve, e.g., distribution of sampling averages. Pareto DiagramA chart which ranks, or places in order, common occurrences. Primary Control VariablesThe major independent variables used in the experiment. ProbabilityThe chance of something happening; the percent or number of occurrences over a large number of trails. ProcessA particular method of doing something, generally involving a number of steps or operations. Process CapabilityThe relative ability of any process to produce consistent results centered on a desired target value when measured over time. Process Control ChartAny of a number of various types of graphs upon which data are plotted against specific control limits. Process MapFlow chart to analyze a process by breaking it down into its component steps, and then gaining a better understanding of the process, step-by-step. Process SpreadThe range of values which a given process characteristic displays; this particular term most often applies to the range but may also encompass the variance. The spread may be based on a set of data collected at a specific point in time or may reflect the variability across a given amount of time. Quality Functional Deployment (QFD)Structured methodology to identify and translate customer needs and wants into technical requirements and measurable features and characteristic. This tool is used to identify Critical to Quality Characteristics (CTQCs). RandomSelecting a sample so each item in the population has an equal chance of being selected; lack of predictability; without pattern. Random CauseA source of variation which is random; a change in the source (“trivial many”variables) will not produce a highly predictable change in the response (dependent variable), e.g., a correlation does not exist; any individual source of variation results in a small amount of variation in the response; cannot be economically eliminated from a process; an inherent natural source of variation. Random VariationVariations in data which result from causes which cannot be pinpointed or controlled. Regression AnalysisA statistical technique for determining the relationship betweenone response and one or more independent variables. RobustThe condition or state in which a response parameter exhibits hermetically to external cause of a nonrandom nature; e.g., impervious to perturbing influence. Rolled YieldThe combined resulting quality level, stated as a percent acceptable, that occurs when several processes known to produce defects at some rate are combined to produce a product. For example, a product that requires 100 steps, each of which produces a yield of 98.78% will produce a rolled yield of 0%, that is, no acceptable products. Scatter DiagramA diagram that displays the relationships between two variables. SigmaStandard deviation; an empirical measure based on the analysis of random variation in a standard distribution of values; a uniform distance from the mean or average value such that 68.26% of all values are within 1 sigma on either side of the mean, 95.44% are within 2 sigma, 99.73% are within 3 sigma, 99.9% are within 4 sigma and so forth. Sigma LevelA statistical estimate of the number of defects that any processwill produce equivalent to defects per million opportunities for that process. Six Sigma QualityA combination of verified customer requirements reflected in robust designs and matched to the capability of production processes that creates products with fewer then 3.4 defects per million opportunities to make a defect. World-class quality. A collection of tools and techniques for raising quality to worked-class levels. Stable ProcessA process which i free of assignable causes, e.g., in statistical control. Standard DeviationA statistical index of variability which describes the spread. Statistical ControlA quantitative condition which describes a process that is free of assignable/special causes of variation, e.g., variation in the central tendency and variance. Such a condition is most often evidenced on a control chart. Statistical Process ControlThe application of statistical methods and procedures relative to a process and a given set of standards. Transaction ProcessesFor Six Sigma purposes, defined as any business process that contributes to customer satisfaction or impacts operating efficiency and which is designated as a focus for process improvement. Such efforts will be led by the process owner, with teams being led by specially trained transaction project leaders and/or by certified