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2.008 QUALITY

2.008 QUALITY. Market Research. Conceptual Design. Design for Manufacture. Unit Manufacturing Processes. Assembly and Joining. Factory, Systems & Enterprise. Manufacture. Outline. What is quality? Variations Statistical representation Robustness Read Chapter 35 & 36.

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2.008 QUALITY

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  1. 2.008QUALITY

  2. Market Research Conceptual Design Design for Manufacture Unit Manufacturing Processes Assembly and Joining Factory, Systems & Enterprise Manufacture

  3. Outline • What is quality? • Variations • Statistical representation • Robustness Read Chapter 35 & 36

  4. What is quality?

  5. Variations • Part and assembly variations • Variations in conditions of use • Deterioration

  6. Variable OutcomeResults from measuring intermediate or final process outcome Men Machines Outcome is measured • Unit of measure (mm, kg, etc.) •The measurement method must produce accurate and precise results over time Materials Methods Outcome examples • Shaft O.D. (inches) • Hole distance from reference surface (mm) • Circuit resistance (ohms) • Heat treat temperature (degrees) • Railcar transit time (hours) • Engineering change processing time (hours)

  7. Technological Development • Physical masters • Engineering drawings • Go / No-Go gage • Statistical measurement • Continuous on-line measurement

  8. +/-0.1” +/-0.1” 4.5” 1.5” +/-0.004” 1.00” Engineered Part • Design specification +/-0.004” • Process specification

  9. Engineered Part (cont’d) • Raw data, n = 20 1.0013 0.9986 1.0015 0.9996 1.0060 0.9997 1.0029 0.9977 1.0042 0.9955 1.0019 0.9970 0.9992 1.0034 0.9995 1.0022 1.0020 0.9960 1.0013 1.0020 • 6 Buckets .994 -.996 2 .996 -.998 2 .998 -1.000 5 1.000 -1.002 6 1.002 -1.004 3 1.004 -1.006 2

  10. +/-0.1” +/-0.1” 4.5” 1.5” +/-0.004” 1.00” 7 6 5 4 Frequency 3 2 1 0 .994 - .996 - .998 - 1.000 - 1.002 -1.004 – .996 .998 1.000 1.002 1.004 1.006 Diameter, in. Engineered Part • Design specification +/-0.004” • Process specification

  11. Failing balls hit these pins and go either left or right Ball part way through row of pins Manufacturing Outcome: Central Tendency

  12. 45 40 35 30 Frequency 25 20 15 10 5 0 0.71670.75058 0.852220.8861 0.8861-0.91998 0.750580.78446 0.784460.81834 0.953860.98774 0.81834-0.85222 0.91998-0.95386 Mass, g Central TendencyHalloween M&M mass histograms: n = 100

  13. Mean 0.89876 Median 0.90183 Std. Dev 0.04255 Minimum 0.71670 Maximum 0.98774 0.7000 0.7580 0.8160 0.8740 0.9320 0.9900 Dispersion Mass of Halloween M&M/ g, n=100

  14. Statistical Distribution • Central tendency • Sample mean (arithmetic): • Sample median • Measures of dispersion • Standard deviation • Variance • Range

  15. f( x) x a b P z Normal Probability Density Function Probability Normalized

  16. P 0 Z1 Areas under the Normal Distribution Curve

  17. P 0 Z1 Areas under the Normal Distribution Curve

  18. Normal Distribution Example Take a M&M with mass = 0.9g, based on our calculated normal curve, how many M&M’s have a mass greater than 0.9g? Z = (0.9 -0.89876) / 0.04255 = 0.29 Area to the right of Z=0.29, from table on previous page: P = (1 -0.6141) = 0.3859 So, the number of M&M’s with a mass greater than 0.9g # = P*n = 0.3859 * 100 = 39

  19. Robustness Not precise Precise Not accurate Accurate

  20. Tokyo Color Density San Diego T-5 T T+5 D C B A B C D Quality Loss $100 T-5 T T+5 A Tale of Two Factories

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