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Reconfigurable Inspection Machine (RIM). Overview. The RIM and the inspection methodology What can the RIM measure and how? Comparison of measurement results Conclusion and future work. Reconfigurable Inspection Machine (RIM). Engine cylinder head. Vision system. Laser probes. - PowerPoint PPT Presentation
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Reconfigurable Inspection Machine(RIM)
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
2
Overview
• The RIM and the inspection methodology
• What can the RIM measure and how?
• Comparison of measurement results
• Conclusion and future work
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
3
Reconfigurable Inspection Machine (RIM)
Laser probes
Slide system
Engine cylinder headVision system
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
4
General Measurement Capabilities of the RIM
• Dimensional:
Distance between edges, between surfaces or between holes
Dimensions of holes and inclination angles of chamfers
• Geometrical:
Flatness of surfaces
Parallelism between surfaces
• Surface Texture:
Porosity defects on a surface
Surface roughness (ongoing research)
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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• Different measurements due to contact probe radius.
• Different point densities.
• Different flatness calculation algorithms.
• Device dependant characteristics.
RIM and Conventional CMM Measurements Differ. Why?
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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Interpretation Is Required for Contact Probe. Why?
P
)( *jxo
*jx
*jz
R
)( *jxz
Interpreted measurement point
Actual surface point
*je
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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The “Virtual Ball” Algorithm
*jx
ix
RxxRx *ji
*j
),(max)( **
** jiRxxRx
j xxHxojij
Ball contact point
i*ji
*ji zxxRxxH 22 )(),(
Rxo j )( *Interpreted height:
R
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
8
Measurement example with Virtual Ball interpretation
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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Flatness Calculation by RIM
Flatness
2 planesParallel to best fit planeThat confine the Measured points
LSQ fit plane toMeasured points
Filter outliers outside 3 zoneLaser measured points
“Virtual ball” interpreted points
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
10
Width and Parallelism Calculation by RIM
Width
Point confining planesparallel to datum
Daturm, LSQ fit plane tojoint face measured points
Filter outliers outside 3 zoneLaser measurements joint face
“Virtual ball” interpreted pointsjoint & cover faces
Laser measurements cover face
Best fit plane of cover faceparallel to datum
-
+Parallelism
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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Measurement Results
• Parts were measured by Inspec using a CMM.• Results compared RIM measurements:
– Distance between joint and cover face– Parallelism between joint and cover face– Flatness of joint and cover face– Hole diameter– Distance between holes centers
• Manual measurements serve as additional reference
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
12
Result Comparison
Laser measurements
Simulated contact probe
measurements
RIM
Interpretation using the
“Virtual ball”
CMM measurements
Inspec
reference measurements
Manual Inspection
Vision measurements
ComparisonPart
RIM
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
13
• Measurements were obtained in two methods:• Point on 3 lines (yellow)• Point spread (yellow + blue)
Inspec Measurements
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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• Parts width was measured manually with 25µm accuracy.
• Part width was measured in 8 points and parallelism was deduced.
• Hole diameters were measured twice.
Manual Measurements
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
15
values for filtered data (outliers outside 3 zone removed after virtual ball interpretation)
Allowed Tolerance : 119 0.2
Part WidthInspec(mm)
RIM (mm)
Difference (mm)
Part 1 119.550 119.531 0.019
Part 3 118.975 119.106 -0.131
Part 4 118.332 119.011 -0.679
Part 5 119.140 119.132 0.008
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
16
values for filtered data (outliers outside 3 zone removed after virtual ball interpretation)
Allowed Tolerance : 119 0.2
Part Width - DetailedInspec
(mm)
RIM mean (mm)
RIM Plus tolerance
(mm)
RIM Minus tolerance
(mm)
Manual (mm)
Part 1 119.550 119.531 0.060 -0.092
Part 3 118.975 119.106 0.038 -0.038 119.115
Part 4 118.332 119.011 0.630 -0.635 118.934
Part 5 119.140 119.132 0.407 -0.396 119.095
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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values for filtered data (outliers outside 3 zone removed after virtual ball interpretation)
Allowed Tolerance : 0.100
Parallelism Between Joint and Cover Faces
Inspec(mm)
RIM (mm)
Difference (mm)
Manual (mm)
Part 1 0.063 0.116 -0.053
Part 3 0.975 0.035 0.940 0.030
Part 4 0.306 1.229 -0.923 0.870
Part 5 0.653 0.758 -0.105 0.480
//
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
18
values for filtered data (outliers outside 3 zone removed after virtual ball interpretation)
Allowed Tolerance : 100 µm
Flatness of Joint FaceInspec(µm)
RIM (µm)
Difference (µm)
Part 1 22 35 -13
Part 3 37 41 -4
Part 4 65 37 28
Part 5 48 46 2
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
19
values for filtered data (outliers outside 3 zone removed after virtual ball interpretation)
Allowed Tolerance : 100 µm
Flatness of Cover FaceInspec(µm)
RIM (µm)
Difference (µm)
Part 1 20 74 -54
Part 3 40 22 18
Part 4 27 44 -17
Part 5 22 22 0
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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Allowed Tolerance : 16.2 0.2 mm
Hole DiameterInspec(mm)
RIM (mm)
Difference (mm)
Manual (mm)
Part 1 - 1 16.032 16.128 -0.096 15.964
Part 4 - 1 16.103 15.966 0.137 16.027
Part 5 - 1 16.304 16.138 0.166 16.147
Part 1 - 2 16.022 16.036 -0.014 15.976
Part 4 - 2 16.031 16.043 -0.012 16.147
Part 5 - 2 16.248 16.193 0.055 16.147
12
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
21
Allowed Tolerance : 306 0.1 mm
Distance Between HolesInspec(mm)
RIM (mm)
Difference (mm)
Part 1 305.991 305.768 0.223
Part 4 305.981 305.752 0.229
Part 5 305.984 305.803 0.181
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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values for filtered data (outliers outside 3 zone removed after virtual ball interpretation)
Maximum deviation : 6 µm
Different number of probesRIM
3 scan lines(µm)
RIM 2 scan lines
(µm)
Difference (µm)
Part 1 35 31 4
Part 3 41 39 -2
Part 4 37 31 6
Part 5 46 46 0
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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Conclusions• Overall, laser measurements are in the same range
• The RIM may be used for process monitoring with a backup CMM.
• Differences may result from:– Different measurement methods– Different measurement environment– Different algorithms– Measurement uncertainties (imperfect calibration)– Human error (further testing required)
• Different number of probes per face (2 or 3) had negligible effect on the results
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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Future Work
• Further result analysis.
• Repeating CMM measurements for additional reference.
• Testing for repeatability and reliability.
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
25
Acknowledgements
• This research was supported in part by the NSF Engineering Research Center for Reconfigurable Machining Systems under the grant EEC95-92125.
• The RIM project team.
• Dr. G. Sirat from Optimet.
• Cummins metrology department.
NFS Engineering Research Center for Reconfigurable Manufacturing SystemsCollege of engineering, University of Michigan
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RIM Team
Project Team:
ERC: Dr. Reuven Katz ERC Dr. Steve Segall ERCDr. Jacob Barhak ERC
Students: Anuj Gupta EECS Avinash Kalyanaraman EECSGlenny Tjahjadi EECS Yoou-Soon Kim ME
Industrial partners:
Ashish Kachru Cummins Robert J. Hogarth GM Tim Lock Vision Solutions, Inc.