【正文】 rolling Our Quality“...will bring GE to a whole new level of quality in a fraction of the time it would have taken to climb the learning curve on our own.”John F. Welch, Jr.1995 GE Annual Report6? Overview What Does “Sigma” Mean? Sigma is a Measure of the Consistency of a ProcessIt (??? is Also the 18th Letter in the Greek Alphabet!Why Does GE Need A Quality Initiative?GE Raising The Bar– New Goal to be “Best in the World” vs. 1 or 2– Customers are Expecting More, we Must Deliver– “Shipandfix” Approach no Longer Tolerated in the Market– Aim to Speed Past Traditional Competitors in 5 Years– Goal Consistent with Reduced Total CostsWe Must Acknowledge Our Vulnerabilities? Poor Quality That Impacts Customers? Problems with NPI? Too High Internal Costs6? Overview We Need a Major Initiative to Move From Where we Are to Where we Want to be6? Overview Why Does GE Need A Quality Initiative?40%35%30%25%20%10%15% 5%Cost of Failure (% of Sales)Defects per Million 233 6210 66,807 308,537 500,000Sigma 6 5 4 3 2 1 Estimated Cost of Failure in US Industry is 15% of Sales。 The Potential Performance of a Process, Corrected for an OffTarget MeanLSL USL? ? ?Process Mean181。 176。 176。 Note: Time is a Factor Only if TemperatureChanges Significantly6? Overview Step 9.....Establish Tolerances on “Vital Few” (Xs)How do we Ensure Oven Temperature is Controlled?? Data Suggests 350 ( 5 ) is best Temperature to Reduce Taste Variation? Brand A Flour to be Used Except in Case of Emergency? “BETTER BREAD” to Search for Better Alternative Supplier of Flour Just in Case176。 Z T Target 0A 3? ProcessThe Definitions of YieldFinal Test Process(Process 4) PassProcess 3Process 1 Process 2100(Units Tested) 65 70 8291Yield 1 Yield 2 Yield 3 Loss 1 Loss 3 Rejects Loss 2 9 9 12 5? First Time Yield (Yft)= Units PassedUnits Tested= 65 70= ? Rolled Thruput Yield (Yrt)= (Yield 1) (Yield 2) (Yield 3) . . . . = 91 82 65 70( ( ( () ) ) ) = 100 91 70 82? Normalized Yield (Ynm)==1/n(Yrt)()1/4 = ( n: Total Number of Processes ) 6? Overview Yield Exclusiveof ReworkProbability ofZero DefectsAverage Yield of All Processes6? Overview The Impact of ComplexityRolled YieldNumber of Operations 1 10 100 1,000 10,000 1,000,000Process Mean Centered on Each Operation 1 10 100 1,000 10,000 1,000,000Rolled YieldNumber of Operations As the Number of Operations Increases, a HighRolled Yield Requires a High ?? for Each Operation 5? 4? 3? 6? 6? 5? 4? 3?Process Mean Shifted ?? at Each Operation6? Overview Baselining Benchmarking an Existing Processp (x)DefectsBenchmarkBaseline Entitlement? Benchmark.....A WorldClass Performance? Entitlement.....Achievable Performance Given the Investments Already Made? Baseline.....The Current Level of PerformanceBaselining = Current Process / Benchmarking = Ultimate GoalSome Basic 6?Related Tools6? Overview Scatter Diagram Over Slept Car Would Not StartWeather Family ProblemsOtherPareto Diagram Frequency ofOccurenceReasons for Being Late for WorkArrival Timeat WorkTime Alarm Went OffMaterials PeopleThe HistogramControl Charts6? Overview Some Basic 6?Related ToolsThe Fishbone DiagramMeasurements Methods TechnologyStatementCause EffectBeing Late for WorkPlot of Daily Arrival Time 9:157:00 7:15 7:30 7:45 8:00 8:15 8:30 8:45 9:00Average ValueNumber ofPeopleArrivingat CRDTime6? Overview LCLUCLRange ChartROut of Control ConditionLCLXUCLX Bar ChartSome Basic 6?Related ToolsLCL = Lower Control LimitUCL = Upper Control LimitX = MeanR = Average RangeMonitors Changes in Average or Variation Over TimeDesign of Experiment