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handout8 - Derived units square meter cubic meter hertz...

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Unformatted text preview: Derived units square meter cubic meter hertz kilogram per cubic meter meter per second radian per second meter per second squared radian per second squared neWIon newton per sq meter sq meter per second newton-second per sq meter jouie watt coulomb volt ‘ . volt per meter ohm farad Weber ’ hem-y ' tesla ‘ ampere per meter ampere lumen candeia per sq meter lux N's/m- (5") (kg/ms) (N/m) (J/s) (A/s) (W/A) (V/A) (A/s/V) (V/S) (V/s/A) (Wb/mi) (Cd/5r) (lm/m3) mu...” .., INSPECTION euro TEST 18.l Damascus of Fundamental Units of the SI System Definition 650 7” 7‘ 1'“ i {:e “A w.lf pa. :3 Wavelen-gthiin vacuo ol' the unperturbed tranSttton lam—ads tn ' Kr /Mass ol’the international kilogramac Sevres France [/3! 556 925 974 7 ot‘the tropical year at l2h ET. 0 January 5" e g 0 “£1 / £900. supplementarily defined in [964 in terms of {he cesium F_ 4: M. O to F. 3: M. 0. transition, the Frequency assigned being 9 I93 63l 770 Hz I , l , /. Defined in the thermodynamic seal: ‘ e” V ' " triple point onater (freezin: The constant cun'ent which: if maintained in two straight parallel conductors of infinite length, of negligible circular sections. and placed 1 m apart in a vacuum. will produce between these conductors a force equal to 2 X l0" mks unit of Force per meter of length. L; (“wk a} (at ”1/60 of the intensity 'ot‘l cm2 ol‘a perfect radiator at the temperature of freezing platinum. H a i a. I, An amount ofsubszance whose weight in grams numerically equals the molecular formula weight. \\ l<{105v—k""' e by assigning 373.l6 K to the g point. 37315 K = 0°C) Amp: v‘i / QUALITY CONTROL HANDBOOK PRIMARY R EFERENCE STANDARDS TRANSFER STANDARDS PuL L4. ‘b‘ WORKING STANDARDS GAGES, INSTRUMENTS AND EQUIPMENT USED TO MEASURE PROCESS AND PRODUCT CHARACTERISTICS FIG. 18A Hierarchy of standards. MST" 9‘0 mew 0“ Fame gtdo #— B. Measurement Terms and Definitions C. Gage Capability Chapter 9 Measurement System and Gage Capability Accuracy is the deviation of the measured or ob- served value from the true value. Precision of a measurement is related to its re- peatability in terms of the deviation of a group of observations from a mean value. While the terms accuracy and precision are often used interchangeably, they could be distinguished as accuracy being the measure of the approach to a true value, while precision is a measure of consist- ency or repeatability. (See Harris in Background References.) Repeatability is often used to describe measure- ment variation obtained when one person meas— ures the same dimension or characteristic several times with the same gage or test equipment (some? times referred-to as "equipment variation"). Reproducibility is a term popularized in the auto- motive industry as representing the variation in measurement averages when more than one per— son measures the same dimension or characteristic using the same measuring instrument. Stability refers to the variation in-the measure» ment averages when the measuring instrument values are recorded over a Specified time interval. Other terms used to describe certain properties of gages include: sensitivity, resolution, calibration accuracy and amplifieaeion, and others. See sources such as Farago twisted in the background references for additional explanations of'terms. When referring to gage capability. we are getter ally looking at the accuracy, repeatability, reproa ducibility and stability combined into a single value. These capability elements have been depicted graphically by Charbonneau and Webster. (See Background References). At the left is shown the repeatability or the ex- pected variation in one person's readings The_av- gages fig three different people are shown as XA, X“, and Xr, and the reproducibility distribution represents the average variation. Accuracy would be calculated by averaging 33“, in, 32c, and taking the difference between [this figure and the true value. Stability appears as a distribution in the second time period and again is represented as a variation in average values. The capability is de— picted as the diafiference between the extremes en- countered over the‘time period. Chapter 9 D. Gage Capability Studies (cont’d) 2. Formal Gage Study A more comprehensive gage study can identify the proportion of variation contributed by both the gage repeatability and reproductibility, commonly referred to as a gage R & R study. For example, poor reproducibility would indicate a need for operator training in use ofthe gage or a requirement for better readability A lack of re— peatability would suggest the need for gage main- tenance, gage redesign or selection ofanother type of measuring device. Thisrcomplete gage study couldbe performed with several different operators‘tinspecwrs or testers) each performing several different mea— surement trials. To illustrate, we can use a form similar to that presented by Charhonneau and Webster for up to three trials for each of three different operators, The average range (R) is used to estimate the equipment variation (repeatability), and the ap— praiser variation (reproducibility) is derived from the differences in averages (inn). Measurement System and Gage Capability For both repeatability and ceproducibility, varia— tion is based on 2575 standard deviations (99% t the normal distribution). The combined variabil- ity is determiaed by adding the variance of both and the R & R is determined. Using this. method, the generayll y recognized critt ria for gage acceptability aod‘capability (R & R divided by the specification tolerance) is: ' Under l0%: acceptable gage - I0% to 30%: may be acceptable ' Over 30%; gauge is anncceplable and should ‘ be correctedror'replaced Chuplcr 9 Measurement System and-Gage Capability Variable Gage Study (Shun Method) Inspeclur A InSpectoar 8 Range (A ~13) Sum M Ranges: (All numbers in lcnlhs ohm inch). " ‘ .7, 1 Average Range (fl) 3 g = ___i._ = 4L : Gage Emu : 4.33 ('fi) = 4'53 [‘4 1 # Gage Errur I H 41/ 7 [572.5/9}. Specificmiun 'l‘ulcruncc 40 . H > l 40 [42 Chapter 9 ‘ Measurement System and Gage Capability Measurement System/Gage Capability Calculation Worksheet ' PallIASm‘ Name Jhdff Gage Name Mtcrnmt far _em Madam "em-mm SpedficaIiou .375 5 . I202. Gage type / [he/'1 Zevo Equals , J7 g); Parmo 1’15 5’56 Operalm A B C SamplaNo (s1 Tiial 2nd Ttial 3rd Tn'al Range Isl Trial 2011 Trial and Ttial ' Range 15! Thal 2nd Tvial 3rd Trial I Ranga ' JL I5 57 .z A 57 5? 56 2 5e, 57 5:, l 2 L3 5.2 4,2 / a, 1/ £4! 6 ’r’ 0 a 1—] 44,! 4 1/ ,1 3 £6 54 55 9.2 57 55 5c, :2 15 5; 55 a 4 .57 65 5L ,2. 5c .57 I5 01 5‘ .57 55 .2 5 5) .53. .57 I 59 (,0 Lo 1 57 an 60. 3 6 54 55 52.1 .2 40 .57 J7 J .55 .57 5s; ,2 7 a 5; 54 / 5! 5: 5!: -z if 55 57- ,2 a .57 67 66 / 57 5f 57 I ‘57 527 J7 ' r _9 7 50’ 5.5 54 / 7 £4 if 7 4,5 7_/_ 5‘?” 5+! 45 / "J 55’ _ .57 £7 / 5/ pa £0 / 5.? 57 40 7 0L 'I'olals 5X2 673 571/ I51 5931 59/ if; Af 5 74 5);; 535' /g n. m! i a“ 43’ 7— a - M: N—v—x Sum I71 9 Sum / 7 70 Sum /7.;/_7 R. 57.45 I 2.. L590 if éxgg 3:33:33me {Lfi J‘fifux , £5 , _37 Y7 # Metefiisumeaverageolfi. . E . fit /.4 __‘ / 5- + 1.; V ._. 4/75 ,7 [:2 D. , 327lol2lrialsov25316r3tfials ' 3 ll any individual range exceeds this Hunt. the measwemerdl 0: reading should be reviewed. repealed. corrected Mdiscarded as appropnale. and new averages and ranges should be computed, Measurement SyslemIGage Capabitil y Analysis : Equipment Variation ("Repealabflily") , Kfi — J‘05 x A a I 4- 5‘? 'Flepoalauihly when: K. " 456lov2llialSOrBflSlotSlriais. ,2 7 / 3 7 .....7~» ‘0 . 7 OperalorVanaliaM Reproduclblllly l 7 K,X.... , fl 1: —__ — Repmducihility where: K, : 3.65lor20peralors or 2770 loraoperalors. i... is Ihe dlflerence between lhe max; and min; To1al"fiepealabilily" and “Hepwducibillly” Variation (Ra-RI r V lFlepeatabililyF + (Reproducmiliwr Gage Capahmly :Wllff l"( 3.7 )2=\/Jo,91 + [3-5? =Jiél: 59 Gage flammability Delermlnallun: . rcialeageCauaWY‘F‘Lm : flag-5'7 = W m .004 ~'—— Nulas i Analysts perimmed by: Dale ...
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