【正文】 ariables Missed by “One Factor at a Time”, and (ii) Efficiently Searches for “Sweet Spot” in Parameter Space The Variables Time of Departure from Home Route Taken to Work The Approach Vary time of Departure and Route Simultaneously, in a Systematic Fashion The Result A Better Combination Allowing 15 More Minutes of Sleep!!! Actual Commuting Time Averages (minutes) 3 2 1 7:15 7:30 7:45 8:00 8:15 Route 17 20 23 21 19 15 18 20 19 16 12 15 21 20 18 Original Conclusion Best Combination “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 Bread YEAST FLOUR Using a 12 Step Process 6? Overview The “BETTER BREAD” Company Step 1.....Selecting “Critical to Quality” (CTQs or Y) What is Important to the Customer? ? Rise ? Texture ? Smell ? Freshness ? Taste Y = Taste!! 6? Overview Measure Step 2.....Defining Performance Standards for CTQs or Y 6? 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 7 Y = 1 2 3 4 5 6 7 8 9 10 Target Defects Worst Best But.....Is this the Right System? Measure 6? Overview Step 3.....Validating the Measurement System for Y How 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。 176。 The Potential Performance of a Process, Corrected for an OffTarget Mean LSL USL ?? ?? ??Process Mean 181。 = 0??Cpk 1 (??? 0??3?? = Cpk = OffTarget Penalty Target 3??181。 177。 One Taste Unit Measure 6? Overview Step 4.....Establish Product Capability for Y (Taste) This is a 3? Process! 7 Defects (ratings below 7) 24 Ratings (from our panel) = .292 292,000 Defects per 1,ooo,ooo Loaves OR 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 10 of Ratings Rating 6 4 3 2 1 1 4 3 Defects 7 Target = 8 Analyze How Do We Approach This? ? Bake Several Loaves Under “Normal” Conditions ? Have Taster Panel Again Do the Rating ? Average Rating is ? But Variation is too Great for a 6? Process 3 x 10 + 4 x 9 + 6 x 8 + 4 x 7 + 3 x 6 + 2 x 5 + 1 x 4 + 1 x 3 1 + 1 + 2 + 3 + 4 + 6 + 4 + 3 6? Overview Step 5.....Define Improvement Objectives for Y (Taste) How do we Define Improvement? ? Benchmark the Competition ? Focus on Defects ( . taste rating 7) ? Determine What is an “Acceptable Sigma Level” ? Set Improvement Objectives Accordingly Maybe a 5? Process Will Suffice! 1,000,000 100,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 3 4 5 6 7 “ BETTER BREAD” Baking Process Best Competitor Range for Improvement Defects Per Million Sigma Scale Freihofer WONDER Pepperidge Farm Sunbeam Analyze 6? Overview Step 6.....Identify Sources of Variation in Y (Taste) How do we Determine the Potential Sources of Variation (Xs)? ? Have the Chefs Brainstorm ? Some Likely Ones Might be: Amount of Salt Used Brand of Flour Baking Time Baking Temperature Brand of Yeast YEAST FLOUR Multiple Sources: Chefs, Suppliers, Controls Analyze 6? Overview Step 7.....Screen Potential Causes of Variation (Xs) How do we Screen for Causes of Variation (Xs)? ? Design an Experiment ? Use Different Sources of Potential Variation ? Have Panel Rate the Bread Used in the Experiment ? Results Lead to the “Vital Few” Causes YEAST FLOUR Source Conclusion Negligible Major Cause Negligible Major Cause Negligible Focus on The