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© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 In a...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
Defini...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
Defini...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Vari...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 GNP ...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 GDP ...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Main...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Vari...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Accu...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
Precis...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
High p...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Supp...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
_
y
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...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Bias...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Prob...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Prob...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Popu...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Accu...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Unbi...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Exam...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
Precis...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Prec...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
_
y
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...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Stat...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Hard...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Hard...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Boei...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
a = 0....
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
 Shap...
© 2008-2015 Young-Woo Park
PrecisionEngineering
Department of Mechatronics Engineering
CHUNGNAM NATIONAL UNIVERSITY
Precis...
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1. introduction

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1. introduction

  1. 1. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  In an industrialized nation, manufacturing is the main wealth creating activity.  About 1/3 of the value of all goods & services produced in a nation  Manufacturing Definition
  2. 2. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY Definition
  3. 3. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY Definition Ref.: OECD(2004), ( )는 국가별 수위도시 인구비중
  4. 4. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Various Concepts of National Income  Gross National Product (GNP)  Gross Domestic Product (GDP)  Net National Product (NNP)/National Income  Personal Income Definition
  5. 5. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  GNP (국민 총 생산)  The total money value of all final goods & services produced by the residents of a country in one year period  GNP = C + I + G + (X – M)  C = Consumption Expenditure  I = Investment  G = Government Expenditures  X – M = Net Exports Definition
  6. 6. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  GDP (국내 총 생산)  The total market value at current prices of all final goods & services produced within a year by the factors of production located within a country  Distinction between GDP and GNP  GDP = GNP – Net Foreign Income from Abroad Definition
  7. 7. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Main thrusts in manufacturing engineering  Automation  CAD/CAM/CAE/…  Manufacture with higher precision  precision engineering  Sustainable Manufacture  green growth, green economy, … Definition
  8. 8. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Various Definitions  Precision engineering may be broadly defined as work at the forefont of current technology, implicitly in the field of metrology and manufacturing technology [McKeown].  The achievement of dimensions & tolerances in the order of 0.01 mm and surface roughness of 0.001 mm (1 nm)  Any technology related to features of nanometer scale: thin film, fine particles, chemical synthesis, advanced microlithography, and so forth [Drexler].  The technology of manufacture to dimensions or tolerances in the range of 0.1 – 100 nm (from the size of the atom to the wavelength of light) [Franks]. Definition
  9. 9. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Accuracy  the degree of closeness of a measured OR calculated quantity to its actual (true) value  Precision  the degree of reproducibility Precision, Accuracy, & Smoothness
  10. 10. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY Precision, Accuracy, & Smoothness
  11. 11. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY High precision, but low accuracyHigh accuracy, but low precision Precision, Accuracy, & Smoothness
  12. 12. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Suppose you machine a certain dimension of a part to length L. machine with a machine tool measure the machined parts with a sufficiently accurate instrument plot the results as the frequency distribution Precision, Accuracy, & Smoothness
  13. 13. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY _ y _ y Precision, Accuracy, & Smoothness
  14. 14. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Bias  the difference between the mean value & specified dimension  Mathematical expression  dm = L – where, L = specified (or nominal) dimension, = sample mean _ x _ x Precision, Accuracy, & Smoothness
  15. 15. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Probability Distribution  The probability distribution of a discrete random variable (r.v.)  a list of probabilities associated with each of its possible values  The probability density function of a continuous r.v.  a function which can be integrated to obtain the probability that the r.v. takes a value in a given interval. Precision, Accuracy, & Smoothness
  16. 16. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Probability Distribution  A random variable is a function that associates a unique numerical value with every outcome of an experiment.  A coin is tossed ten times. The r.v. X is the number of tails that are noted. X can only take the values 0,1,....,10, so X is a discrete r.v.  A light bulb is burned until it burns out. The r.v. Y is its lifetime in hours. Y can take any positive real value, so Y is a continuous r.v. Precision, Accuracy, & Smoothness
  17. 17. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Population mean, m  the mean of a probability distribution (=population)  Mathematically y continuous y discrete  m = E(y), where, E = expected value operator.  Sample mean,  A point estimator of a population mean (=the mean of a sample)  n x x i _         m      n 1i ii )y(Py )y(yf Precision, Accuracy, & Smoothness _ x
  18. 18. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Accuracy,   = t-distribution value when the degree of freedom is f = n-1 and the probability is (1-a).  n = the sample size (i.e. number of data points used)  a = the significance level  n = the unbiased variance  a non-negative number which gives an idea of how widely spread the values of the random variable are likely to be. n x) 2 ,(t na fd  d ) 2 ,(t a f     n 1i 2 i )xx( 1n 1 n Precision, Accuracy, & Smoothness
  19. 19. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Unbiased  The long-run average or expected value of the point estimator should be the parameter that is being estimated.  E( ) = = = = = m ∴ is an unbiased estimator of m. y              n y E n 1i i        n 1i iyE n 1   n 1i iyE n 1  n 1in 1 m y Precision, Accuracy, & Smoothness
  20. 20. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Example  If we take n = 21 and n = 4 mm2 with a = 0.05 = 95% reliability, = ? ∴ = 0.192 mm.  The accuracy of the machining process is evaluated as 0.192 mm with a probability of 0.95 (or 95% reliability). ) 2 ,(t a f n x) 2 ,(t na fd  Precision, Accuracy, & Smoothness
  21. 21. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY Precision, Accuracy, & Smoothness
  22. 22. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Precision, e  measured by how small the dispersion e is from the mean value  Mathematically  Example = 4.18 mm.  this machining process has a precision of 4.18 mm with a probability of 0.95. n a fe x) 2 ,(t n a fe x) 2 ,(t Precision, Accuracy, & Smoothness
  23. 23. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY _ y _ y  Why high precision? Precision, Accuracy, & Smoothness
  24. 24. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  State of Current Technology  PE is the science underlying the manufacture of high precision machinery.  Traditional precision machines: watches and cameras  Computers and their peripheral equipments  Video equipments  Aerospace equipments, measuring equipments (including astronomical telescopes, etc.)  High precision machine tools  Telecommunication devices Precision, Accuracy, & Smoothness
  25. 25. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Hard disk drive  Aluminum alloy disk + magnetic head  Rotational speed = 5,200 ~ 7,200 RPM Precision, Accuracy, & Smoothness
  26. 26. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Hard disk drive  RPM is getting higher.  ball bearing  air bearing  aluminum alloy disk  ceramic disk Precision, Accuracy, & Smoothness
  27. 27. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Boeing B747-200 Precision, Accuracy, & Smoothness
  28. 28. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY a = 0.3~1.0 mm ± 0.02 mm q = 5°  Plane-reflection type diffraction grating  The critical component of spectroscope  A spectroscope is a device that lets us find out what things are made of. It works by taking light and splitting it up into its component colors. Precision, Accuracy, & Smoothness
  29. 29. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY  Shaper-type ruling engine  engraves grooves spaced at 600 to 1200 lines per mm. = 83 grooves onto the width of a hair, about 100 mm.  accumulated pitch error must not exceed 0.2 mm for 1200 grooves. Precision, Accuracy, & Smoothness
  30. 30. © 2008-2015 Young-Woo Park PrecisionEngineering Department of Mechatronics Engineering CHUNGNAM NATIONAL UNIVERSITY Precision, Accuracy, & Smoothness

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