【正文】 s6? Overview SCREENING OPTIMIZATIONCHARACTERIZATION? For Experiments Involving a Large Number of Factors? Useful in Isolating the “Vital Few “ from the “Trivial Many”? For Experiments Involving a Relatively Small Number of Factors? Useful When Studying Relatively Unplicated Effects Interactions? For Experiments Involving Only 2 or 3 Factors? Useful When Studying Highly Complicated Effects RelationshipsDOE is More Effective Than Testing One Factor at a Time6? Overview Using the “One Factor at a Time” Approach Reduce Commute to Work to 15 Minutes (without working an abnormal work schedule) The GoalThe Variables Time of Departure from Home Route Taken to Work The Approach Try 3 Potential Routes at Current Departure Time (7:45), Select the Best Vary the Departure Time ‘til we get to 15 MinutesTime of Departure3217:15 7:30 7:45 8:00 8:15RouteCombination SelectedThe ResultUse Route 2 andLeave at 7:15 to Reach Goal6? Overview Using “Design of Experiments” (DOE)Time of DepartureDOE (i) Better Accounts for Interactive Variables Missed by “One Factor at a Time”, and (ii) Efficiently Searches for “Sweet Spot” in Parameter SpaceThe Variables Time of Departure from Home Route Taken to Work The Approach Vary time of Departure and Route Simultaneously, in a Systematic FashionThe ResultA Better Combination Allowing 15 More Minutes of Sleep!!!Actual Commuting Time Averages (minutes)3217:15 7:30 7:45 8:00 8:15Route17 20 23 21 1915 18 20 19 1612 15 21 20 18 Original Conclusion BestCombination“Sweet Spot” Reduce Commute to Work to 15 Minutes (without working an abnormal work schedule) The Goal A Practical Example (The “Cookbook”)6? Overview 6?.....and Baking BreadYEAST FLOURUsing a 12 Step Process6? Overview The “BETTER BREAD” CompanyStep 1.....Selecting “Critical to Quality” (CTQs or Y)What is Important to the Customer?? Rise? Texture? Smell? Freshness? TasteY = Taste!!6? Overview MeasureStep 2.....Defining Performance Standards for CTQs or Y6? Overview How Could We Measure Taste (Y)?? Panel of Tasters? Rating System of 1 to 10? Target: Average Rating at 8? Desired: No Individual Ratings (“defects”) Below 7Y = 1 2 3 4 5 6 7 8 9 10 TargetDefectsWorst BestBut.....Is this the Right System?Measure6? Overview Step 3.....Validating the Measurement System for YHow Could We Approach This?? Blindfolded Panel Rates Several Loaf Samples ? Put “Repeat” Pieces from Same Loaf in Different Samples ? Consistent Ratings* on Pieces from Same Loaf = “Repeatability”? Consistent Ratings* on Samples Across the Panel = “Reproducibility” “Repeatability” “Reproducibility” Suggest Valid Measurement Approach Panel Member Loaf 1 Loaf 2 Loaf 3 A 5 8 9 B 4 9 1 C 4 9 2 D 8 9 8 E 4 8 2 F 5 9 1 G 8 9 2* Within 177。 T TargetA 3? Process] The Potential Performance of a Process, if it Were on Target6? Overview Long Term Capability (Cpk)CpCpk =Long Term Capability RatioExampleCp = 1 (previous chart)Target = ?181。 Taking GE From a 3? to a 6? Company Will Save ~ $ Billion per Year!Why “Six Sigma”?? Proven Successful in “QualityDemanding” Industries ., Motorola, Texas Instruments (many process steps in series)? Proven Method to Reduce Costs? Highly Quantitative Method – Science and Logic Instead of Gut Feel? Includes Manufacturing Service (close to customer) and Provides Bridge to Design for Quality Concepts? Has Support and Commitment of Top ManagementIt Works!!