preferred principal axis of inertia spheres for john conklin · preferred principal axis of inertia...
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Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Preferred Principal Axis of Inertia Spheres for John Conklin
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Overview • Background of LISA program and customer requirements
• Sphere manufacturing
– Three parts
– Two parts
• Sphere joining
• Iterative lapping
• Iterative metrology
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Sphere Manufacturing Approaches
Two
Piece
Method
Three
Piece
Method
Geometry Requirements: ~ 50mm diameter
k1 > 0.1
Density loss < 20%
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Manufacturing Times
Three Piece Two PieceFixture manufacturing time 12 hours 1 hour
Fixtures made 1 4
Cap (2 per sphere) 5 hours
Core (1 per sphere) 9 hours
Hemisphere (2 per sphere) 2.5 hours
Total manufacturing time per sphere 19 hours 5 hours
Total spheres made 2 10
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Design for 3-piece Method
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Manufacturing
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
From Hex to Round
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Cap Manufacture
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Cap Fixturing
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Core Manufacture
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Core Fixturing
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Completed 3-part Sphere
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Design for 2-piece Method
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Internal Geometry Modification
Sharp internal features
Filleted internal features
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Critical Internal Features
– Tapped hole for 6-32
machine screw
– Fixture alignment surfaces
– Sphere alignment post and
hole
– Well for silver braze wire
preform
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Internal Geometry Machining
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Fixturing for Second Operation
Internal fixture alignment geometry
machined in, and seen through,
a cast acrylic block.
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Hemispherical Surface Machining
• Spherical surface cutting
– Roughing
– Surfacing
• Face tolerance set to +0.005” and +0.0005”
(0.127 mm and 0.0127 mm)
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Joining Operations for Sphere Halves
Process Selection and Joining Procedure
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Joining Operations • Adhesive
• Interference fit
• Mechanical fastening
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Joining Operations
• Heat Operations
– Solder
– Braze
– Weld
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Laser Welding
• Brass alloys are
not good
candidates
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
E-Beam Welding
• Fixturing
• Waitlist
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Brazing
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Joint clearances of .001" and .005" (0.076 to 0.126mm)
25 ksi (172 MPa) typical shear strength
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Brazing Possibilities
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Brazing Process
Method Braze Material Braze Object Results
Oven Soft solder paste Blocks
Oven Silver solder paste Blocks
Rosebud Silver solder paste Blocks
Mapp Torch Soft solder Blocks
Rosebud Silver solder preform Blocks
Rosebud Silver solder preform Extra halves
Rosebud Silver solder preform Spheres
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Spheres Joined
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Lapping and Polishing
• Flat lap and spherical lap
• Lubricants may improve
performance
• Wet vs. dry method
• Dry lapping: Lap must be soft
relative to part
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Spherical Lap • Self aligning geometry
• Naturally removes high points on sphere
• Two phases
– Phenolic lap rough cutting brass parts
– Cast iron lap final cutting and polishing brass parts
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Practice Lapping
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Lapping Glass Marbles • Paint removal is easy!
• Large scale material removal is slow.
• Approximately 24 hours of total lapping time:
– Removal rate ≈0.03mm (0.0012”) per hour on diameter
– Highly dependent on grit quality and water content
• 60 grit aluminum oxide
• 2-3 hour grit life-span
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Marble Results • Slow but measurable convergence to sphericity
• No “eggs” or ellipsoids
• Valuable lessons about grit and lubricant
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Track Wear
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Lapping Brass Parts
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
The Phenolic Lap
2.5 Hours
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
6 Hours
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Brass Lapping Process • 30 hours in phenolic lap with 60 grit
• 10 hours in cast iron lap with 150 grit
6 Hours
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Brass Lapping Status • A work in progress
• Rough cutting works well
• Next steps:
– Fine grits
– Polishing
• Stay tuned for current metrology data
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Metrology
spheres or eggs?
keeping track of diameter and roundness
• Kinematic 3 point mount for repeatable and stable positioning
• Gage 2000 CMM (Coordinate Measuring Machine)
- Repeatable accuracy ~5 micrometer
- About 18 hits per (hemi-) sphere measurement
- Internal software algorithm and backtalk + external MATLAB algorithm for
data analysis
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Measurement Principle
• Measurement results dependant on orientation of the sphere on
mounting bracket
– Brazing joint
– Difference in single parts of sphere
• Each sphere measured in 3 orientations for meaningful information
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Tuesday Wednesday Thursday Friday
Brass Lapping History
Phenolic Lap,
60 Grit, 12
Hours
Cast Iron Lap,
150 Grit, 6
Hours
Phenolic Lap,
60 Grit, 5
Hours
Phenolic Lap,
1000 Grit, 1.5
Hours
Cast Iron Lap,
150 Grit, 7
hoursPhenolic Lap,
60 Grit, 9
Hours
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Evolution of a 2 Part Sphere
Orientation Diameter [mm]
I 50.774 50.722 50.635 50.677
III 50.407 50.324 50.109 50.123
Deviation of roundness [mm]
I 0.055 0.023 0.036 0.033
III 0.255 0.153 0.215 0.192
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Orientation Diameter [mm]
I 50.897 50.673 50.782 50.610
III 51.058 50.889 50.810 50.669
Deviation of roundness [mm]
I 0.136 0.0525 0.084 0.055
III 0.207 0.0681 0.100 0.089
Evolution of a 3 Part Sphere
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Results / Summary
• Average reduction of diameter : ~ 0.195 mm / 0.39 %
• Average of material removed : ~ 781 mm3 / 1.15 %
• Best reduction of roundness deviation : ~ 47.3%
• Avg. reduction of roundness deviation : ~ 25.7 %
• Best achieved roundness dev. : 0.031 mm
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Future
• Iterative process to final LISA test mass
– Measurement of mass center offset and moment of inertia
distribution
– Iteration of fabrication process based on the gained experience
– Adapt the experiences to final material of test mass
Detect Gravitational Waves!
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Thanks and Acknowledgments
• John Conklin
• Richard Peattie at Surface Engineering
• Craig Milroy of the Product Realization Lab
• Karlheinz Merkle of the Varian Machine Shop
• PRL Shop TAs
• Materials Science Shop
• Dave Beach and Dan DeBra
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
Questions?
Please join us up front to look at some of our parts.
Daniel Clark | Mike Dolphin | Marlo Dreissigacker | Martin Trittler | John Ulmen
ME324: Precision Engineering David Beach, Dan DeBra Spring 2007
References • http://www.aladdin3in1.com/solder.htm
• //www.silvaloy.com/brazing_table.php
• http://laser-industrial.com/laser_welding4.html
• http://hussle.harvard.edu/~gabrielse/gabrielse/papers/2001/TheRoadtoAntihydrogen.pdf
• http://www-group.slac.stanford.edu/mfd/ebeam.html
• http://www-group.slac.stanford.edu/mfd/lightms.html