1 / 30

Chapter 6 Statistical Process Control (SPC)

Chapter 6 Statistical Process Control (SPC). Descriptive Statistics. 1. Measures of Central Tendencies (Location) Mean Median = The middle value Mode - The most frequent number 2. Measures of Dispersion (Spread) Range R=Maximum-Minimum Standard Deviation Variance . x. x. x.

jenski
Download Presentation

Chapter 6 Statistical Process Control (SPC)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 6 Statistical Process Control (SPC)

  2. Descriptive Statistics 1.Measures of Central Tendencies (Location) • Mean • Median = The middle value • Mode - The most frequent number 2. Measures of Dispersion (Spread) • Range R=Maximum-Minimum • Standard Deviation • Variance

  3. x x x x x 1 2 3 4 5 6 7 8 µ The Standard Deviation (x-µ)

  4. River Crossing Problem

  5. Inferential Statistics

  6. 68.26% 95.46% 99.73% The Normal (Gaussian) Curve -3-2-1+1+2+3

  7. Red Bead Experiment

  8. Types of Control Charts Quality Characteristic Attribute Variable Type of Attribute X and MR chart No n>1 Defective Defect Yes Constant sample size? Constant sampling unit? Yes Yes No X-bar and R chart n>6 Yes No np-chart No c-chart X-bar and s chart p-chart u-chart

  9. Data Stats • Information • Central Tendency • Dispersion • Shape No Action Decision Action

  10. median median mode mode mean mean Skewed to the right (positively skewed) Skewed to the left (negatively skewed) The Shape of the Data Distribution • “Box-and-Whisker” Plot mean = median = mode • Pearsonian Coefficient of Skewness

  11. Special Cause (Assignable) Control Charts Special Cause (Assignable) +3σ Average -3σ Common Cause (Chance or Random)

  12. Standard Error of the Mean Central Limit Theorem Sample (x-bar) Distribution Population (individual) Distribution μ

  13. X-Bar and R Example Rational Subgroup Subgroup Interval

  14. X-Bar and R Control Chart Limits

  15. Attribute Control Chart Limits

  16. p-Chart Example *Note: Use n-bar if all n’s are within 20% of n-bar

  17. β β β The α and β on Control Charts α = .00135 +3σ Average -3σ α = .00135

  18. 3 2 1 Average -1 -2 Out of Control Patterns 8 successive points same side of centerline 2 of 3 successive points outside 2  -3 4 of 5 successive points outside 1 

  19. Control Chart Patterns Instability “Freaks” Gradual Trend Sudden Shifts Cycles “Hugging” Centerline “Hugging Control Limits”

  20. Six Sigma Process Capability 1.5 Cp = 2.0 .54 ppm Cpk = 1.5 3.4 ppm LSL USL

  21. Cause and Effect Diagrama.k.a. Ishikawa Diagram, Fishbone Diagram Person Procedures A B C Process Material Equipment

  22. Vital Few Trivial (Useful) Many Pareto Charta.k.a. 80/20 Rule

  23. The Taguchi Loss Function: L (x) = k (x-T)2 Loss ($) .480 .500 .520 Traditional Loss Function: Loss ($) .480 .500 .520 Taguchi Loss Function

  24. Most “Robust” Setting Response Curves

More Related