6s黑带培训教材(英文).pptx

Process Capability Analysis(Measure Phase)Scope of ModuleProcess VariationProcess CapabilitySpecification, Process and Control LimitsProcess Potential vs Process PerformanceShort-Term vs Long-Term Process CapabilityProcess Capability for Non-Normal DataCycle-Time (Exponential Distribution)Reject Rate (Binomial Distribution)Defect Rate (Poisson Distribution)Process VariationProcess Variation is the inevitable differences among individual measurements or units produced by a process.Sources of Variationwithin unit (positional variation)between units (unit-unit variation)between lots (lot-lot variation)between lines (line-line variation)across time (time-time variation)measurement error (repeatability reproducibility)Types of VariationInherent or Natural VariationDue to the cumulative effect of many small unavoidable causesA process operating with only chance causes of variation present is said to be “in statistical control” Types of VariationSpecial or Assignable VariationMay be due to a) improperly adjusted machine b) operator error c) defective raw materialA process operating in the presence of assignable causes of variation is said to be “out-of-control”Process CapabilityProcess Capability is the inherent reproducibility of a process’s output. It measures how well the process is currently behaving with respect to the output specifications. It refers to the uniformity of the process.Capability is often thought of in terms of the proportion of output that will be within product specification tolerances. The frequency of defectives produced may be measured ina) percentage (%)b) parts per million (ppm)c) parts per billion (ppb)Process CapabilityProcess Capability studies can indicate the consistency of the process outputindicate the degree to which the output meets specificationsbe used for comparison with another process or competitorb)a)c)Process Capability vs Specification Limitsa) Process is highly capableb) Process is marginally capablec) Proces