Metrology is science considering measurement

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2 Metrology is science considering measurement Categories: Scientific deals with organization and development of etalons and their conservation(highest level) Industrial deals with function of measuring devices used in industry in manufacturing and testing processes Legal deals with precision of measurement in situations where the exact measurement is necessary for justice of economic transactions, health and security

3 Fields of metrology: Weight Electricity Length Time and frequency Thermometry Ion radiation and radioactivity Volume Acoustic measurements Etc.

4 Continuity Is property of measured value or etalon value that can express the relation to reference on national or international level. This relationship is expressed through an uninterupted chain of relationships between components where the unceratainity is known.

5 Unit definition International etalons National etalons Home national etalons Foreign national etalons Reference etalones Company etalones Etalons are changing with development of science Length etalon - meter 1795 bar made of brass 1799 bar made of platinum and iridium ,73 times the wave length of radiation that is equal to transition of electron from quantum level 2p10 to level 5d5 in Cryptonium distance reached by light in time of 1/ second. Measurement

6 Basic procedure for securing the continuity of measurement is the calibration. Calibration is aquiring metrological characteristics of measuring device. This is made by referencing them to etalones. Reasons for calibration: 1) To secure that the value measured by the device is same as to another device or method 2) To secure the measured value is correct 3) To secure the reliability of measuring device.

7 Direct measuring device measures directly the wanted quantity or property Indirect measuring device measures another quantity or property from that the wanted quantity or property can be calculated or derived

8 Absolute I acquire directly a value of quantity or property Comparatory I acquire the difference between the etalon and the measured value only

9 caliper micrometer block gauges pasameter microskope lengthmeter laserinterferometer CMM (Coordinate measuring machine)

10 basic comunal device - calliper precision: 0,1; 0,05; 0,02 mm (nonius, Vernier scale) 0,01 mm (digital) range mm types: classical(nonius) digital with indicator

11 with nonius (Vernier sc.) outer dimension inner dimension depth

12 digital presentation: display display + output (RS232, USB) solar powered IP66 waterproof cover

13 indicator

14 The most common device: caliper

15 precision: 0,01; 0,005 (mechanical) 0,005 0,0001 (digital) range (0 25) ( ) mm types: mechanical digital

16 measurement outer dim. inner dim. depth

17 special types: plate tubes prizmatic

18 special types: plate tubes prizmatic tolerances thread threetouch holemicrometer

19 micrometer ,24 2, ,51 2,49 0

20 indicator gauge not absolute measurement must watch the hand to see if it did not run the full circle scale division!!!

21 indicator gauge examples

22 accuracy (4 grades): 0,5 0,05 mm (cca 5 mm) 8 4 mm (cca 1 m) range ~ 0, mm types: steel (~ 800 HV) sintered carbide ceramic (~ 1350 HV)

23 properties: ground, polished, lapped no surface protection thin oil film geometric precision primary block accuracy (0,02+0,05.L [m]) mm Ú Sem inář z Tec hnol ogie II. 2. cvič ení

24 dimenstions a set of different dimensions in a box (ex. 32 pcs set) 1,005 mm (1pc) 1,01-1,09 step 0,01 mm (9pcs) 1,1-1,9 mm step 0,1 mm (9pcs) 1-9 mm step 1 mm (9pcs) mm step 10 mm (3pcs) 50 mm (1pc) for specific value = put together parts Handle with care!!!

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26 Together with a two-axis table with micrometric screws it is a universal measuring device The ocular includes the crosshair Two perpendicular lines Three lines rotated 60 Four line rotated 45 Shape lines (thread profiles)

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28 Universal Length Measuring Machine Accuracy 1 0,1 mm Measuring range up to 6 meters

29 Laserinterferometer Accuracy = up to 0,01 mm (depending on measured length) (0,5+1,1.L/1000 ) mm Range: very variable (up to 100 meters)

30 Angle gauges Square for right angle Protractor Sine bar level

31 Like linear block gauges

32 For fast measurements in practical life

33 Mainly 90 Also 45, 60, 120 a 135

34 Rotary arm digital With moving arm

35 Rotary arm digital With moving arm With occular inclinometer

36 Used with block gauges

37 Mechanical hydraulic Gyroscopic - Digital - accelerometer

38 threepin method gauges thread snap gauge microscope Micrometer Problem is that the thread si too complex to be measured. And also that the diameters are not recognizable on the part Nominal diameter (Major and minor diameter)

39 Indirect measurement we measure the Diameter over pins and we can calculate from it the nominal diameter

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41 For pitch measurement Gauge is placed to the thread

42 Thread snap gauge Thread plug gauge

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44 List of tasks: 1. Profile projector measurements (-o-) 2. Cylindrical plug gauge control on microindicator (-o-) 3. Cone measurement on a laboratory microscope 4. Angle measurement with an optical bevel 5. Frontal run-out measurement (-o-) 6. Run-out measurement of a rotary part (-o-) 7. Thread measurement using a three wire method 8. Measurement using a laboratory microscope (-o-) 9. Gear measurement 10. Machine operational accuracy PC evaluated 11. Run-out measurement of a spindle 12. Batch measurement of cylindrical parts

45 Task: Measure the spacing R (distance between center points) of clamping holes in the spring plate. Use the profile projector for the measurement.

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47 Measure and write down the coordinates of tangents of measured holes! Attention! micrometrix thread has two revolutions per milimeter Ring scale division is 50 scales. Carefully read if you see the half-milimeter line on the main scale + add the value from the ring.

48 Hole 1 Coordinate X1.1 X1.2 Y1.1 Y1.2 Center coordinate Diameter value in axis Diameter value Spacing

49 Problem: Decide about the applicability of the GO and NOT GO ends (good and bad ends) of a workshop cylindrical plug gauge for hole diameter control. Use the microindicator for measuring.

50 Deviation with a block gauge (40 mm) = -35 Deviation with a measured part = 12 Total deviation = 12-(-35) = 47 Scale = 0,001 mm Dimension of deviation = 47 scales = 0,047 mm Dimension of measured part = ,047 = 40,047 mm!!! Results discussion!!!

51 Problem: Measure the frontal run out of a universal clamping head used for workpieces clamping in both open and closed state. Write down the values and express them by using a column chart. (measured values in columns, separate columns for different places of measurement).

52 Position [mm] clamp Check no.1 Open -0,02-0,01 0,01-0,01-0,02 Closed -0,04-0,03 0,02 0,01-0, clamp open closed

53 clamp 1 clamp 2 clamp3 clamp 4 open closed MAX MIN Runout = maximum value ex. RUNOUT OF OPEN CLAMP = MAX-MIN

54 Problem: Measure the radial and axial run-out of rotary (spindle) part Express the results with a polar chart and mark the maximum runout value in this chart. deviations for axial runout [mm]

55 Problem: Measure the nominal thread diameter d 2 and the lead (pitch) of a metrical thread on given part. Compare the measured values with nominal values in table. Discuss the results. Thread cross hair 2 1 d 2 movement of crosshair 3

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