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The Lean Six Sigma Pocket Toolbook A Quick Reference Guide to Nearly 100 Tools for Improving Process Quality, Speed and Complexity Contents Chapter 1: Using DMAIC to Improve Speed, Quality, and Cost ...................................................................1 Define ...........................................................................................4 Measure........................................................................................ 8 Analyze ........................................................................................ 12 Improve ........................................................................................ 14 Control.......................................................................................... 17 Kaizen DMAIC.............................................................................. 20 Project selection ...........................................................................26 Chapter 2: Working With Ideas ....................................... 27 Brainstorming................................................................................27 Affinity diagrams........................................................................... 30 Multivoting.....................................................................................31 Chapter 3: Value Stream Mapping and Process Flow Tools ............................................................... 33 Process mapping ......................................................................... 34 Process observation .................................................................... 36 SIPOC...........................................................................................38 Process mapping steps ................................................................39 Transportation and spaghetti (workflow) diagrams ......................42 Swim-lane (deployment) flowcharts ............................................. 43 Value stream maps (basic)........................................................... 45 Flowchart and value stream symbols ...........................................49 Value-add (VA) vs. non-value-add (NVA) analysis....................... 49 Time value maps...........................................................................52 Value-add chart (task time or takt time chart) .............................. 53 Chapter 4: Voice of the Customer (VOC) .......................... 55 Customer segmentation ............................................................... 56 Sources of customer data............................................................. 58 Collecting VOC: Interviews........................................................... 59 Collecting VOC: Point-of-use observation ....................................60 Collecting VOC: Focus groups .....................................................61 Collecting VOC: Surveys.............................................................. 62 Kano analysis ...............................................................................64 Developing critical-to-quality requirements .................................. 67 iv Chapter 5: Data Collection ..................................................69 Types of data .............................................................................. 70 Input vs. output data ....................................................................71 Data collection planning............................................................... 72 Measurement selection matrix..................................................... 74 Stratification factors......................................................................75 Operational definitions ................................................................ 76 Cautions on using existing data .................................................. 77 Making a checksheet .................................................................. 78 Basic checksheets....................................................................... 79 Frequency plot checksheet.......................................................... 80 Traveler checksheet.....................................................................80 Location checksheet.................................................................... 81 Sampling basics .......................................................................... 81 Factors in sample selection........................................................ 83 Stable process (and population) sampling..................................84 Formulas for determining minimum sample size (population or stable process).................................................... 85 Measurement System Analysis (MSA) and Gage RandR Overview.................................................................. 87 Gage RandR: Collecting the data ..................................................88 Interpreting Gage RandR Results ................................................. 90 MSA: Evaluating bias................................................................. 96 MSA: Evaluating stability............................................................ 97 MSA: Evaluating discrimination.................................................. 99 MSA for attribute/discrete data .................................................. 100 Chapter 6: Descriptive Statistics and Data Displays ..................................................................... 104 Statistical term conventions........................................................105 Measures of central tendency (mean, median, mode)............................................................... 106 Measures of spread (range, variance, standard deviation) ........................................ 108 Boxplots ..................................................................................... 110 Frequency plot (histogram).........................................................1 1 1 Normal distribution......................................................................114 Non-normal distributions and the Central Limit Theorem.......................................................... 114 Chapter 7: Variation Analysis .......................................... 117 Review of variation concepts ..................................................... 118 Time series plots (Run charts) ................................................... 119 Run chart table........................................................................... 121 Control chart basics ...................................................................122 Selecting a control chart............................................................. 123 Control charts for continuous data .............................................123 Subgrouping for continuous data................................................125 Control limit formulas for continuous data ................................. 127 Factors for Control Chart Formulas ........................................... 128 V Creating an ImR Chart ................................................................128 Creating X,R charts or ,S charts.................................................. 129 Control charts for attribute data .................................................. 130 Creating p-, np-, c-, and u-charts ................................................132 Control limit formulas for attribute data........................................132 Assumptions for interpreting control charts................................. 133 Interpreting control charts (Tests for Special Cause Variation) ............................................ 133 Background on process capability calculations .......................... 135 Confusion in short-term vs. long-term process capability calculations.................................... 137 Calculating process capability .................................................... 138 Chapter 8: Identifying and Verifying Causes ....................141 PART A: Identifying potential causes ........................................141 Pareto charts ............................................................................ 142 5 Whys.......................................................................................145 Cause-and-effect diagrams (fishbone or Ishikawa diagrams) ............................................... 146 CandE Matrix.................................................................................148 PART B: Tools for confirming causal effects .............................149 Stratified data charts.................................................................. 150 Testing quick fixes or obvious solutions ....................................152 Scatter plots ..............................................................................154 Hypothesis testing overview...................................................... 156 Confidence intervals ................................................................. 157 Type I and Type II errors, Confidence, Power, and p-values ................................................................. 158 Confidence intervals and sample size .......................................160 t­test Overview ......................................................................... 161 1-Sample t-test ......................................................................... 162 2-Sample t-test ......................................................................... 163 Overview of correlation ............................................................. 165 Correlation statistics (coefficients)............................................. 166 Regression overview..................................................................167 Simple linear regression ........................................................... 168 Multiple regression ....................................................................169 ANOVA (ANalysis Of VAriance) ................................................173 One-way ANOVA....................................................................... 174 Degrees of Freedom.................................................................. 178 ANOVA assumptions................................................................. 179 Two-way ANOVA....................................................................... 180 Chi-Square test ......................................................................... 182 Design of Experiments (DOE) notation and terms..................... 184 Planning a designed experiment................................................185 DOE: Full-factorial vs. Fractional-factorials (and notations)........................................... 189 Interpreting DOE results ........................................................... 192 Residual analysis in hypothesis testing......................................195 vi Chapter 9: Reducing Lead Time and Non-Value-Add Cost ......................................................... 197 Basic Lean concepts ..................................................................199 Metrics of time efficiency............................................................ 201 Time Traps vs. Capacity Constraints.......................................... 203 Identifying Time Traps and Capacity Constraints ...................... 204 5S Overview............................................................................... 206 Implementing 5S ........................................................................207 Generic Pull System .................................................................. 213 Replenishment Pull Systems ..................................................... 216 Two-Bin Replenishment System.................................................219 Computing minimum safe batch sizes........................................ 222 Four Step Rapid Setup Method.................................................. 223 Adapting Four Step Rapid Setup for service processes............. 227 Total Productive Maintenance (TPM) ........................................ 228 Mistake proofing and prevention (Poky yoke) ................................ 232 Process balancing design principles ..........................................234 Work cell optimization ................................................................235 Visual Process Controls .............................................................237 Chapter 10: Complexity Value Stream Mapping and Complexity Analysis .............................................................. 241 Product/service family grid .........................................................242 Complexity Value Stream Map (CVSM) .....................................243 Process Cycle Efficiency (PCE) .................................................245 The Complexity Equation ...........................................................245 Complexity matrix....................................................................... 246 PCE destruction calculations (for a Complexity Matrix) ............. 247 Substructure analysis................................................................. 248 "What-if" analyses with Complexity Matrix data..........................250 Chapter 11: Selecting and Testing Solutions ................ 253 Sources of solution ideas............................................................254 Benchmarking ............................................................................254 Tips on solution selection .......................................................... 255 Developing and using evaluation criteria ................................... 256 Solution selection matrix.............................................................258 Pairwise ranking......................................................................... 261 Cost evaluation........................................................................... 264 Impact/effort matrix ....................................................................264 Pugh matrix ............................................................................... 265 Other evaluation techniques....................................................... 269 Controls assessment matrix....................................................... 269 Failure Modes and Effects Analysis (FMEA) ............................. 270 Pilot testing................................................................................. 273 Index ........................................................................... 277