1 Temperature Measurement for Precise Dimensional Metrology Anusorn Tonmueanwai Department of Dimensional Metrology National Institute of Metrology (Thailand) 2 3 Contents - Background and Concept of temperature effect to length and dimension measurement - Case Study : - Micrometer for external measurement calibration using Gauge Block - Vernier caliper using Gauge Block using gauge block/caliper checker - Gauge block calibration by comparison method - How NMI can be reduce the uncertainty of measurement by temperature effects - Summary
Transcript
1
Temperature Measurementfor
Precise Dimensional Metrology
Anusorn TonmueanwaiDepartment of Dimensional Metrology
National Institute of Metrology (Thailand)
2
3
Contents
- Background and Concept of temperature effect to length and
dimension measurement
- Case Study :
- Micrometer for external measurement calibration using
Gauge Block
- Vernier caliper using Gauge Block using gauge
block/caliper checker
- Gauge block calibration by comparison method
- How NMI can be reduce the uncertainty of measurement by
temperature effects
- Summary
4
ISO 1
• ISO 1 is an international standard that specifies the standard reference temperature for geometrical product specification and verification.
• The temperature is fixed at 20 oC, which is equal to 293.15 Kelvin's and 68 degrees Fahrenheit.
• Due to thermal expansion, precision length measurements need to be made at (or converted to) a defined temperature.
• ISO 1 helps in comparing measurements by defining such a reference temperature.
• The reference temperature of 20 °C was adopted by the CIPM on
15 April 1931, and became ISO recommendation number 1 in 1951.
5
6
Effects of Temperature on Dimensional Gageswww.tangentlabs.com
We would like to know temperature and coefficient thermal expansion
77
Temperature Effects on Length Measurement ?
www.ptb.de
8
Temperature Effect on Manufacturer SpecificationMitutoyo Catalog
9
Temperature Effect on Manufacturer SpecificationMitutoyo Catalog
10
Temperature Effect on Manufacturer SpecificationMitutoyo Catalog
11
Temperature Effect on Manufacturer SpecificationMitutoyo Catalog
Influence due to varying coefficients of thermal expansion on the measurement results. This graph shows the highest difference between the reference gauge and the gauge block to be calibrated made of steel as per ISO 3650.
Influence due to varying coefficients of thermal expansion on the measurement results. Difference between steel and ceramic gauge blocks [(11,5 ±1,0).10-6 K-1 and (10,0±1,0) . 10-6 K-1 respectively].
http://www.tesabs.ch/FlipBook/EN_flip/index.html
23
Gauge Block with Calibrated Coefficient of Thermal ExpansionMitutoyo, Catalog No.E4334
2424
Stabilized temperature
The gauge block which is expanded by handling is kept on a
measurement stage until it reaches the same temperature as
room temperature.
The procedure of deciding on keeping time:
(1) A standard gauge block is set on a measurement stage. It is kept
until it reaches room temperature.
(2) The work GB which carried out the usual handling（cleaning, checking) is set on a measurement stage.
(3) Measurement is started and
it measures at several
minutes intervals.
(4) A measurement result
is shown in graph and the
time by which the size was
stabilized is found.
25
Source of Uncertainties
26
Calibration and MeasurementCapabilities in the context of the CIPM,MRA
27
Guideline for Uncertainty of Measurement
28
Examplefor Difference Uncertainties
of Micrometer (External measurement)
Range: 0-25 mm to 475-500 mm
Calibration using Gauge Block
Difference temperature during measurement A) 5 degreeB) 3 degreeC) 2 degreeD) 1 degree
E) 0.1 degree
29
Source of Uncertaintyfor Micrometer Calibration using Gauge Block
29
ls
lds
lfxlpx
lmx
lx
lws
lix
lx x x x tx
ls x s x ts
lpslfs
30
3131
Uncertainty calculation on difference temperature; u(t)
mm 00299.0
3
C 3
C
1105.11mm 150
3
3)(
o
o6
0
sx
i
ttl
tctu
32
Difference Uncertainty Comparision with Difference Temperature
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
2.5
0
5.1
0
7.7
0
10
.30
12
.90
15
.00
17
.60
20
.20
22
.80
25
.00
50
.00
75
.00
10
0.0
0
12
5.0
0
15
0.0
0
17
5.0
0
20
0.0
0
25
0.0
0
30
0.0
0
40
0.0
0
50
0.0
0
Nominal Value (mm)
Un
ce
rta
inty
(m
icro
me
ter)
Diff Temp 5 degree
Diff Temp 3 degree
Diff Temp 2 degree
Diff Temp 1 degree
Diff Temp 0.1 degree
33
Examplefor Difference Uncertainties
of Vernier Caliper (External measurement)
Range: 0-1000 mm
Calibration using Gauge Block
Difference temperature during measurement A) 5 degreeB) 3 degreeC) 2 degreeD) 1 degree
E) 0.1 degree
343434
Source of Uncertaintyfor Vernier Caliper Calibration using Gauge Block
Standard Value (GB) = Unknown Value (Vernier Caliper)
Difference temperature during measurement A) 1 degree
B) 0.1 degreeC) 0.05 degree
39
Example of Gauge Block Calibration
referencegauge block
sts
xtx
ParallelismLos
to= 20 oC
0
Temperature ts, tx
Flatness
Resolution 0.01 m
Loxgauge block under test Length Laboratory; NIMT
Gauge Block Calibration
by 2 probes Comparator
40
Corrections due to materials
Recommended values for flattening compensation when calibrating gauge blocks made of deferent materials
41
Gauge Block with Calibrated Coefficient of Thermal ExpansionMitutoyo, Catalog No.E4334
4242
Corrections due to temperature
Influence due to varying coefficients of thermal expansion on the measurement results. This graph shows the highest difference between the reference gauge and the gauge block to be calibrated made of steel as per ISO 3650.
Influence due to varying coefficients of thermal expansion on the measurement results. Difference between steel and ceramic gauge blocks [(11,5 ±1,0).10-6 K-1 and (10,0±1,0) . 10-6 K-1 respectively].
TESA Catalog
4343
Common Gauge Block Material Property
4444
Stabilized temperature
The gauge block which is expanded by handling is kept on a
measurement stage until it reaches the same temperature as
room temperature.
The procedure of deciding on keeping time:
(1) A standard gauge block is set on a measurement stage. It is kept
until it reaches room temperature.
(2) The work GB which carried out the usual handling（cleaning, checking) is set on a measurement stage.
(3) Measurement is started and
it measures at several
minutes intervals.
(4) A measurement result
is shown in graph and the
time by which the size was
stabilized is found.
45
46
47
48
49
Uncertainty form temperature correction,
Base on the reference steel gauge block set (112 pcs.) grade 00, Mitutoyo,
which have been calibrated by PTB, Germany, give the data of linear thermal
expansion coefficient (as) is (10.91)10-6 K-1 and that rectangular probability
distribution (as) can be assumed. The under test steel gauge block set, grade
0, Mitutoyo base on the calibration certificate and Inspection of the
manufacturer’s data the linear thermal expansion coefficient (x) is
(10.91)10-6 K-1, and that rectangular probability distribution (x) can be
assumed.
Combining the two rectangular distributions the average of linear thermal
expansion coefficient is triangular distributed within the limits 210-6 K-1.
)()[( ttl
50
Calculate the average of Linear thermal expansion (s & x)
1,6109.10
2
)6109.10()6109.10(
K
2XS
1,610408.0
6
)6101()6101(
)()()(
K
uuu
6
xs
51
Calculate the difference temperature a gauging points between gauge blocks (t)
C
C
xtstt
,0
),00.2000.20(
C
C
tuk
;015.0
;00.2
03.0
)(00.2
nty UncertaiExpanded
Upper probe
Lower probe
Reference gauge block
Unknown gauge block
52
Calculate the difference Linear Thermal Expansion ()
1,0
1),6109.10()6109.10(
K
K
xs
1,610816.0
1,6
6102
)(6
LTE ofError ePermissibl Maximum
K
K
u
53
Calculate the difference Temperature at gauging points and ambient temperature ( )
C
C
txtstt
,0
,00.202
)00.20()00.20(
02
C
C
tu
,29.0
,3
5.0
)(3
mperatureambient te ofStability
t
54
Reference to EA-4/02:1996 paragraph S4.13, equation (S4.3), page 38 of 79
xuxuxuxxux)x(xu 2
2
1
2
2
22
11
22
2212
Approximate 1 : x1 = av u(x1) = u(av)
x2 = t u(x2) = u(t)
Approximate: 2 : x1 = u(x1) = u()
x2 = tav u(x2) = u(tav)
)()(
)]()[(
tLtL
ttL
xx11 xx22 xx11 xx22
55
Uncertainty budget for Steel gauge block, grade 0s = 1/oC t s = 20.00 oC
x = 1/oC t x = 20.00 oC
av = 1/oC t o = 20.00 oC
u (av) = 1/oC t = 0.00 oC
= 1/oC tav = 0.00 oC
u ( = 1/oC u (t) = 0.015 oC
u (tav = 0.29 oC
Quantity
l s 100.00002 mm 0.011 m 9.00E-08 l Normal 1 0.011 m 9.00E-08 l l D 0 mm 0.012 m 1.44E-07 l Rectangular 1 0.012 m 1.44E-07 l
l vs 0 mm 0.0022 m - Rectangular 1 0.002 m l IND -0.000083 mm 0.0058 m - Normal 1 0.006 m l c 0 mm 0.0185 m - Rectangular 1 0.018 m
0 - 1.73E-07 l Special -1 1.73E-07 l
0 - 2.36E-07 l Special -1 2.36E-07 l
l vx 0 mm 0.0038 m - Rectangular -1 0.0038 m -
u 2 ( l x ) 0.0006 m2 1.14E-13 l 2
u ( l x ) 0.0253 m 3.38E-07 ll x 99.999937 mm Normal k = 2 0.05 m 6.8E-07 l
l =100 mm0.118 m
Estimate
x iX i
Uncertainty Contribution,Standard Uncertainty
u(x i )
Absolute Relative
Effective degree of freedom
Probability Distribution
Sensitivity Coefficient
c i Absolute Relative
0.00E+00
8.16E-07
1.15E-05
1.15E-05
1.15E-05
4.08E-07
56
Uncertainty budget for Steel gauge block, grade 0s = 1/oC t s = 20.00 oC
x = 1/oC t x = 20.50 oC
av = 1/oC t o = 20.00 oC
u (av) = 1/oC t = 0.50 oC
= 1/oC tav = 0.25 oC
u ( = 1/oC u (t) = 0.1 oC
u (tav = 0.50 oC
Quantity
l s 100.00002 mm 0.011 m 9.00E-08 l Normal 1 0.011 m 9.00E-08 l l D 0 mm 0.012 m 1.44E-07 l Rectangular 1 0.012 m 1.44E-07 l l vs 0 mm 0.0022 m - Rectangular 1 0.002 m l IND -0.000083 mm 0.0058 m - Normal 1 0.006 m l c 0 mm 0.0185 m - Rectangular 1 0.018 m
0 - 1.17E-06 l Special -1 1.17E-06 l
0 - 4.56E-07 l Special -1 4.56E-07 l l vx 0 mm 0.0038 m - Rectangular -1 0.0038 m -
u 2 ( l x ) 0.0006 m2 1.60E-12 l 2
u ( l x ) 0.0253 m 1.27E-06 ll x 99.999937 mm Normal k = 2 0.05 m 2.5E-06 l
l =100 mm0.304 m
0.00E+00
8.16E-07
1.15E-05
1.15E-05
1.15E-05
4.08E-07
Estimate
x iX i
Uncertainty Contribution,Standard Uncertainty
u(x i )
Absolute Relative
Effective degree of freedom
Probability Distribution
Sensitivity Coefficient
c i Absolute Relative
57
Uncertainty budget for Steel gauge block, grade 0s = 1/oC t s = 20.00 oC
x = 1/oC t x = 21.00 oC
av = 1/oC t o = 20.00 oC
u (av) = 1/oC t = 1.00 oC
= 1/oC tav = 0.50 oC
u ( = 1/oC u (t) = 0.5 oC
u (tav = 1.00 oC
Quantity
l s 100.00002 mm 0.011 m 9.00E-08 l Normal 1 0.011 m 9.00E-08 l l D 0 mm 0.012 m 1.44E-07 l Rectangular 1 0.012 m 1.44E-07 l l vs 0 mm 0.0022 m - Rectangular 1 0.002 m l IND -0.000083 mm 0.0058 m - Normal 1 0.006 m l c 0 mm 0.0185 m - Rectangular 1 0.018 m
0 - 5.77E-06 l Special -1 5.77E-06 l
0 - 9.13E-07 l Special -1 9.13E-07 l l vx 0 mm 0.0038 m - Rectangular -1 0.0038 m -
u 2 ( l x ) 0.0006 m2 3.41E-11 l 2
u ( l x ) 0.0253 m 5.84E-06 ll x 99.999937 mm Normal k = 2 0.05 m 1.2E-05 l
l =100 mm1.219 m
Estimate
x iX i
Uncertainty Contribution,Standard Uncertainty
u(x i )
Absolute Relative
Effective degree of freedom
Probability Distribution
Sensitivity Coefficient
c i Absolute Relative
0.00E+00
8.16E-07
1.15E-05
1.15E-05
1.15E-05
4.08E-07
5858
How we can report the uncertainty of measurement
U95% = 0.0009mm
EA-4/02
• In calibration certificates the complete
result of the measurement consisting of
the estimate y of the measurand and the
associated expanded uncertainty Ushall be given in the form (y U). To this
an explanatory note must be added
which in the general case should have the following content:
– The reported expanded uncertainty of
measurement is stated as the standard
uncertainty of measurement multiplied by the coverage factor k = 2, which for a
normal distribution corresponds to a
coverage probability of approximately
95%. The standard uncertainty of
measurement has been determined in accordance with EAL Publication EAL-R2.
mm in unitl
lmmU
:
103.20008.0 6%95
mm in unitl
lmmU
:
103.20008.0262
%95
59
Summary
1. Temperature measurements are very importance for
dimension metrology.
2. The uncertainties of length & dimension metrology
can be reduces by precise temperature measurement.
3. The uncertainty claim depending on measurement
method.
4. The uncertainty from temperature measurement not
only display but include the temperature sensor.
60
Dimensional metrology Competition
on May 2013, Thailand
Bi-Tech, Bang Na, Bangkok Thailand
6161
2013: Word Skill InternationalDimension Metrology Competition Demonstration
http://www.worldskills.org
6262
2013: Word Skill International for Dimension Metrology Competition Project
62
Start on May 2013, Bangkok, Thailand
6363
Condition
• The Dimension Metrology Skill Competition:
– November 2012, Bangkok, Thailand
• Term number:
– Not over two term per country
– One term include 1 host and 1 participant (not over 21 year old)
• The Ministry of Labour are support:
– Hotel, transportation in Thailand, food
6464
Condition of competition
1. English language to be used in the project2. Technical conditions:
1. The participants should be applications and calibrations the hand tools (micrometer, vernier caliper, dial gauge, dial test indicator and height gauge) according to international standard or national standard (ISO/DIN/AS/JIS etc.).
2. The participants should be evaluate the calibration certificate of standard (gauge block/ring gauge/surface plate etc.) and compensation the measurement results.
3. The participant should be reading the drawing of artifact(ISO1101: Geometric Dimension and Tolerance (GD&T).
4. The participants should be analysis the measurement results(calculate average and standard deviation (by Calculator).
5. The measurement results should be report according to ISO/IEC 17025.
656565
Example: Artifact for Competition
The concept on Competition:• Outside / Inside / Hole / Step / Distance / measurements.• Every parameter have the measuring position line and tolerances .• The participants should be select the measuring tool are suitable with parameter.• The measurement results should be writing on the worksheet and calculation the average and standard deviation. The final results should be compensation with the calibration certificate of each equipment.
