iigdt - gd&t & measurement uncertainty - measurement uncertainty.pdf · 2018. 10. 20. · b89.7 –...
TRANSCRIPT
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
International Institute of GD&TInternational Institute of GD&T
2 Loring Road, Hopkins, MN 553052 Loring Road, Hopkins, MN 55305
www.iigdt.comwww.iigdt.com
GD&T & Measurement Uncertainty
International Institute of GD&TInternational Institute of GD&T
IIGDT
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
Global Simplification of GD&T
ÂÂÂÂ
‰‰‰‰
Profile of a
Surface
Profile of a
Line
3D Surface
Control
2D Surface
Control
Axis Control
ÍÍÍÍPosition
····Flatness
ÈÈÈÈËËËËÁÁÁÁAngularity
Perpendicularity
Parallelism
ÈÈÈÈËËËËÁÁÁÁAngularity
Perpendicularity
Parallelism
‡‡‡‡Straightness
‡‡‡‡Straightness
‚‚‚‚Circularity
„„„„Cylindricity
ÏÏÏÏCircular Runout
ÌÌÌÌTotal Runout
ÓÓÓÓSymmetry
ÓÓÓÓSymmetryÎÎÎÎConcentricity
ÎÎÎÎConcentricity
IIGDT IIGDT
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
Measurement
Eyeball: L=Lest ± 1 inch
Tape: L=Lest ± 1/16 inch
Micrometer: L=Lest ± 0.001inch
Gage block comparator: L=Lest ± 1 microinch
Uncertainty
Cost of metrology
Profit
Target U
Dollars
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
Coordinate Measuring Machines
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
•Correlating Physical Measurements to Functional Parameters
-Input for FEA Models and Experimental Validation
•3D Characterization of Tooling & Product Components
-Standardized Software for Programming Efficiency & Analysis)
-Extraction of Surface Roughness, Waviness, Form
•Maintaining Commodity Plans with Key Measurement Suppliers
•CMMs, Vision Systems, Laser Sensors
Fly Height
Uc
Pitch Torque
2
++
2Roll
Torque
2TotalGramVar
2Slider's
ABSVar+
+P-SA P-StiffxGram Var(2)
POffsetxR-SA R-Stiffx +
Gram Var(2)
R Offsetx
P-LPtCust. SBO+R-LPt
CustSBO+
GramVar(1)
Cust.ZHV
SpringRate x +( ( () ) ) ) )( (
DriveDyn
Functional
Etched Tower Formed DimplePhysical-Suspension
Physical-
Tooling
U1=Mat'l Thickness at bend area
U2=Width at bend area
U3=Length at bend area
U1=Datums
U2=Clamp Force
U3=Clamp Reference Location
U4=B.P. position at assembly
U5=B.P. edge break
U6=B.P. Flatness
U7=B.P. Squareness
U1=Tongue Flantess
U2=Loadbeam Profile
U3=Welding
U4=Heat Treat
U5=Dimple Location
U6=Dimple Height
U1=Flexure Mat'l Thickness
U2=Arm Length
U3=Arm WidthU1=Loadbeam profile under load
U2=Diameter
U3=Position of Tower
U4=Datums
U1=Loadbeam profile under load
U2=Apex Location
U3=Apex Shape
U1 + U2 + U32 22
U1 + U2 + ... + U72 22
U1 + U2 + ... + U62 22
U1 + U2 + U32 22
U1 + U2 + ... + U42 22
U1 + U2 + U32 22
U1=Datums
U2=Dimple Punch Location
U3=Dimple Punch Shape
U1 + U2 + U32 22
FHSTG
2FHSRT
2FHPT
2
12 Contact
CMMs170 Non-Contact
Coordinate Meas. Systems
15+ Other Meas. Systems
(Orbotech, Cognex VM)Micro-Scale CMM
(Contact)
Micro-Scale CMM
(Non-Contact)
Open-Loop Scanning
Geometric Error Analysis
Thermal Modeling
Surface Analysis
3D Analysis
Non-Contact CMM’s
Other Meas. Systems
3D Measurement
Worcester Polytechnic Institute
Center for Holographic Studies and Laser micro-mechaTronics
LOAD BEAM DYNAMICSLOAD BEAM DYNAMICSOEH AND FEM RESULTS OEH AND FEM RESULTS -- MODE 2 AT 2,582 Hz MODE 2 AT 2,582 Hz
Contact
CMM’s
Physical to Functional Characteristic Hierarchy
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
ASME B89 Committee on “Metrology”
Comprised of “7” Divisions:
• B89.1 – Length
• B89.2 – Angles
• B89.3 – Geometry
• B89.4 – Coordinate Measuring Technology
• B89.5 – General Principles and Definitions
• B89.6 – Environment
• B89.7 – Measurement Uncertainty
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
B89.7 – Measurement Uncertainty
“Motivations”
• Need for a uniform approach (GUM) to the treatment of
uncertainty in ASME B89 document
• Need for simplified guidance documents as GUM moves into
industrial arena
• General dissatisfaction with quality of existing written
standards produced by ISO
Design
MeasurementMfg
GD&T
&
Uncertainty
ASME Y14.5M–1994 GUMASME Y14.5.1M–1994
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
ASME B89.7 Committee
“Measurement Uncertainty”
• B89.7.1 - Guidelines for B89 Doc’s
• B89.7.2 - Inspection Planning
• B89.7.3 - Decision Rules
• B89.7.4 - General Principles
• B89.7.5 - Communications
• B89.7.6 - Uncertainty Considerations in Tolerancing
• B89.7.7 - Advanced Uncertainty Concepts
• B89.7.8 - Traceability
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
expansion
bending
temperature
systematic effects
r
φ
∆r
random effects
probingprocess
long term stabilitykinematic anddynamic effects
∆x
x
measurement task
& strategy
basic axis geometry
x
z
y
∑ ∑∑= +=
−
= ∂∂
∂∂
+
∂∂
=N
i
ji
j
N
ij i
N
i
i
i
c xxux
f
x
fxu
x
fu
1 1
1
1
2
2
2 ),(2)(
Variances Covariances
software forevaluation ofmeasurement
[ ]∑ −⋅= 2(),( xxaaxJ iObjective Function:
)(),,()( xxaaxxdxdd iiii −⋅===Distance Equation:
Uncertainty
Management
Physical-to-
Functional
Hierarchies
Dimensional
Management
Design of
Experiments
Reliability
Analysis
Regression
AnalysisHistograms
Fishbone
Diagrams
Repeatability
Gage R&R
ANOVA
Control
Charts
Cp, Cpk
Scientific Approach
Current Approach
HTI Chassis Arm Model
Phase 3 HTI_p3.vsl, May 16, 2000
Session: 20000517-141912
sae14_r 5000 samples
-> Slider/Bond Pad SAE Assembly Method [A|F|0.12] deg
Nominal : 0.645211
Mean : 0.634629
Standard Deviation : 1.660454
Lower Spec Limit : N/A
Upper Spec Limit : 0.050000
Cp : N/A
Cpk : -0.126553
Distribution : Tested Normal
Sample Est Sample Est*
% < Low Limit N/A N/A Low -5.426040 -4.346695
% > High Limit 63.780000 63.761454 High 6.822226 5.615953
% Out of Spec 63.780000 63.761454 Range 12.248265 9.962649
95% C.I. for % Out of Spec : 62.447744 to 65.112256 * Est Range : 99.7300%
F
R
E
Q
0
100
200
300
400
500
600
700
-5.500000 2.500000
USL
-3S +3S
Nominal at Median : 0.645211 HLM Study
HLM Variance : 3.748766
Tolerance Effect
weld_base_p3_FEAT_44_GTP 39.90%-> Comp: weld_base_p3 Feat: weld_base_p3_FEAT_44-> (BONUS 0.00) CompPos(DIA) 0.1270(M)[A|B|C]
load_beam_st_FEAT_1_GTL 15.55%-> Comp: load_beam_st Feat: load_beam_st_FEAT_1-> Position(DIA) 0.0800[A|P]
slider_FEAT_2_GTS 15.55%-> Comp: slider Feat: slider_FEAT_2-> Size +- 0.0400
flex_cu_up___hti_p3_GM4 8.27%-> flex_cu_up___hti_p3 assembleop float
load_beam_st_FEAT_4_GTL 3.89%-> Comp: load_beam_st Feat: load_beam_st_FEAT_4-> Position(DIA) 0.0200(S)[A|B|C]
slider_pos_err 3.89%-> Slider Position Error zone 0.020
weld_base_p3_FEAT_12_GTL 3.82%-> Comp: weld_base_p3 Feat: weld_base_p3_FEAT_12-> (BONUS 0.00) Position(DIA) 0.0076(M)[A|D]
load_beam_st_FEAT_26_GTL 2.78%-> Comp: load_beam_st Feat: load_beam_st_FEAT_26-> Position(DIA) 0.0500[A|B|C]
weld_base_p3_FEAT_7_GTL 2.75%-> Comp: weld_base_p3 Feat: weld_base_p3_FEAT_7-> (BONUS 0.00) Position(DIA) 0.0076(M)[A|D]
96.41%
1 additional contributor(s)
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
expansion
bending
temperature
systematic effects
r
φ
∆r
random effects
probingprocess
long term stabilitykinematic anddynamic effects
∆x
x
measurement task
& strategy
basic axis geometry
x
z
y
∑ ∑∑= +=
−
= ∂∂
∂∂
+
∂∂
=N
i
ji
j
N
ij i
N
i
i
i
c xxux
f
x
fxu
x
fu
1 1
1
1
2
2
2 ),(2)(
Variances Covariances
software forevaluation ofmeasurement
[ ]∑ −⋅= 2(),( xxaaxJ iObjective Function:
)(),,()( xxaaxxdxdd iiii −⋅===Distance Equation:
Analytic Solutions
Graphic courtesy of Dr. Trapet - PTB
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
U95 Estimates Distribution of Multiple
Measurement Systems Over a Period of Time
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
1. Environment
2. Reference Element for Measurement Equipment
3. Measurement Equipment
4. Measurement Setup
5. Software & Calculations
6. Metrologist / Operator
7. Measurement Object
8. Definition of the Characteristic
9. Measuring Procedure
10.Physical Constants & Conversion Factors
Sources of Error / Contributors toMeasurement Uncertainty
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
1. Environment for the measurement
• Temperature: absolute temperature, time variance, spatial variance
• Vibration/noise
• Humidity
• Contamination
• Illumination
• Ambient pressure
• Air composition
• Air flow
• Gravity
• Transients in the power supply
• Pressured air (e.g. air bearings)
• Heat radiation
Sources of Error…
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
2. Reference element of measurement equipment
• Uncertainty of the calibration
• Stability
• Scale mark quality
• Temperature expansion coefficient
• Physical principle: line scale, optical digital scale, magnetic digital
scale, spindle, rack & pinion, interferometer
Sources of Error…
+
+
+
+
+
+
++
+
+
+
++
+
+
+
+
+
+
+
+
+
+
++
+
+
+
++
+
+
+
++
True Center of
Sphere
Incorrect
Center of
Sphere
+++++
+
+
+ +
+
++
+
+
+
+
x+
True Center of
Sphere
Incorrect
Center of
Sphere
+++++
+
+
+ +
+
++
+
+
+
+
x
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
3. Measurement equipment
• Interpretation system
• Magnification-electrical or mechanical - error wavelength!!
• Zero-point stability
• Force stability/absolute force
• Hysteresis
• Guides/slide-ways
• Temperature expansion
• Parallaxes
• Time since last calibration
• Responds characteristic
• Interpolation system - error wavelength
• Interpolation resolution
Sources of Error…
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
4. Measurement setup (excl. the placement and clamping
of the workpiece)
• Cosine errors
• Abbe principle
• Temperature sensitivity
• Stiffness/rigidity
• Tip radius
• Form deviation of tip
• Stiffness of the probe system
• Optical aperture
• Interaction between workpiece and setup
• Warming up
Sources of Error…
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
5. Software and calculations
• Rounding/Quantification
• Algorithms
• Implementation of algorithms
• Number of significant digits in the computation
• Sampling
• Filtering
• Correction of algorithm/Certification of algorithm
• Interpolation extrapolation
Sources of Error…
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
6. Metrologist –operator
• Education
• Experience
• Training
• Physical disadvantages/ability
• Knowledge
• Honest
Sources of Error…
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
7. Measurement Workpiece or Measuring Instrument
• Surface Roughness, Waviness, & Form
• Temperature expansion coefficient
• Weight
• Size
• Shape
• Magnetism
• Cleanliness
• Internal stress
• Creep characteristics
Sources of Error…
0
0.5
1
1.5
2
2.5
3
3.5
0
0.5
1
1.5
2
2.5
3
3.5
-10
0
10
X axis (mm)
Original Surface
Y axis (mm)
Z a
xis
(um
)
0
0.5
1
1.5
2
2.5
3
0
1
2
3
-10
0
10
X axis (mm)
Roughness
Y axis (mm)
Z a
xis
(um
)
0
0.5
1
1.5
2
2.5
3
0
0.5
1
1.5
2
2.5
3
-5
0
5
X axis (mm)
Waviness
Y axis (mm)
Z a
xis
(um
)
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
8. Definition of the Characteristic
• Toleranced feature
• Reference system
• Degree of freedom
• Distance
• Angle
Sources of Error…
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
9. Measuring procedure
• Number of measurements
• Order of measurements
• Duration of measurements
• Choice of principle of measurement
• Reference standard
• Alignment
• Clamping
• Fixturing
• Number of points
• Probing principle
• Drift check
Sources of Error…
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
10. Physical constants and conversion factors
• Lacking knowledge of the correct physical values of e.g. material
properties (workpiece, measuring instrument, ambient air, etc.)
Sources of Error.
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© IIGDT – GD&T: Advanced Applications & Analysis – June 25, 2006
Business Drivers to Support a Decision to
Invest into Aggressive GD&T Training
1. Increased Business due to Increased Capability
2. Increased Profit with Reduced or Eliminated Returns
3. Increased Recognition as a Leading Edge Supplier/Customer
4. Increased Customer Satisfaction Based on Improved Conditions
5. Increased Yield / Reduced Inspection (reduced scrap and rework)
6. Unambiguous and Understood Engineering Requirements
7. Better ability to predict and control processes