7 basic tool for QUALITY

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7 basic tool for QUALITY

  1. 1. © Basic Quality Tools 1. Check Sheets 2. Pareto Analysis 3. Flow Charts 4. Cause & Effect Diagram 5. Histograms 6. Scatter Diagrams 7. Control Charts
  2. 2. © Check Sheets Check Sheet is a gathering interpretation tool. dataand
  3. 3. Check Sheets © • Want to find out cause-wise defects Defects 1 2 3 4 5 6 Total Missing component III IIII II I III IIII 18 No solder II III I IIII 10 Wrong Insertion IIII I IIII II IIII 20 Shorts by component II IIII III 11 Total 11 9 17 59 IIII II 9 6 7
  4. 4. © Check Sheets • More defects on the last day of the week. • Missing components and Wrong Insertion occur more frequently.
  5. 5. © Check Sheets • Check sheet is a data pattern detector. • Check sheet to be used during problem definition stage and after implementation stage.
  6. 6. © Check Sheets 1. Distinguishing between fact and opinion. 2. Gathering data about how often a problem is occurring. 3. gathering data about the type of problem occurring.
  7. 7. © Check Sheets 1. Confirmation Check Sheet – List of steps which must be complete before shipping a product. 2. Defect Location Sheet identify problem areas. –
  8. 8. © Pareto Analysis The Pareto Principle states that only a "vital few" factors are responsible for producing most of the problems. Majority of problems (80%) are due to a few key causes (20%). If we correct these few key causes, we will have a greater probability of success.
  9. 9. © Pareto Analysis Causes Frequency Breakout 37 Hanger 4 Tundish nozzle choking 4 Dummy bar obstraction 5 Overflow 8 Sheer trouble 7 Tundish nozzle erosion 6 Withdrawal problem 12 Bad stream 1 Auto control failure 1
  10. 10. © Pareto Analysis Causes % Freq. % Cum. Freq. Breakout 44 44 Withdrawal problem 14 58 Overflow 9 67 Sheer trouble 8 75 Tundish nozzle erosion 7 82 Dummy bar obstraction 6 88 Hanger 5 93 Tundish nozzle choking 5 98 Bad stream 1 99 Auto control failure 1 100
  11. 11. % © Pareto Analysis 100 80 60 40 20 0 58 67 75 82 100 93 98 99 88 44 14 9 8 7 6 5 5 1 e r .. w le ... ... ang zl. e am fa... ... r flo ub zl k b z s t r ol e a al p ve r o oz r o H r Br aw O er t no ad n ba nt h B h is dr co he dis m y d h S n o it m un ut W T Tu Du A ut o 1
  12. 12. © Flow Chart A flow chart is defined as a pictorial representation describing a process.
  13. 13. © Flow Chart 1. A diagrammatic picture showing all steps or stages in a process. 2. Flow charts help facilitate a greater understanding of the entire process by identifying where problems have occurred or may occur. 3. You cannot improve a process until everyone agrees what the
  14. 14. © Cause & Effect (C-E) Diagram 1. Also called Ishikawa Diagram, Fishbone Diagram. 2. Used to sort out causes of problems. potential 3. Organizes theories by causeand-effect relationships.
  15. 15. © Cause & Effect (C-E) Diagram 4. Provides a guide process analysis. for 5. Highlight likely root causes.
  16. 16. © Machine Quench time Method Coke temp. Nozzle condition Water flow rate Spot quenching Flue temp. Coke moisture Drainage time Quench car speed Man Coke distribution in quench car
  17. 17. © Histogram 1. Graphical representation of individual measured values according to frequency or relative frequency of occurrence. 1. Used to show distribution shape for one variable (location, dispersion).
  18. 18. Daily production data (t) 240 230 220 210 208 200 190 180 37 33 29 25 21 17 13 9 5 170 1 © Histogram
  19. 19. Frequency © Histogram 9 8 7 6 5 4 3 2 1 0 185 190 195 200 205 210 215 220 225 230 Daily Production (t)
  20. 20. © Scatter Diagrams 1. Used to visualize relationship between two variables. Features of a single product. Product output & process input. Two different products. 2. Issues Strength of correlation, non-linear relationships.
  21. 21. Scatter Diagrams © 95 Tensile Strength 90 85 80 75 70 65 60 140 160 180 Hardness 200
  22. 22. © Control Charts 1. Purpose Separate common (inherent) and special causes. Monitor process over time. 2. Used to Identify Cause Variation. Process patterns shifts Special / Cyclic
  23. 23. Control Charts Means ( X-bar) © Xbar and R Chart for : Major OD Minimum 129.85 129.75 MU=129.7 129.65 129.55 LCL=129.52 129.45 Subgroup 0 0.3 Ranges UCL=129.88 5 10 15 UCL=0.3076 0.2 0.1 R=0.09412 0.0 LCL=0.000

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