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Stellarator Core Metrology issues. What are we measuring? When? How do we take the measurements? How do we correlate to CAD data?. NCSX WBS-1 Meeting April 2, 2003. What are we measuring?. Primary component measurements include: In-vessel components - PowerPoint PPT Presentation
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Stellarator Core Metrology issues
NCSX WBS-1 Meeting
April 2, 2003
•What are we measuring?
•When?
•How do we take the measurements?
•How do we correlate to CAD data?
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What are we measuring?
< R0 > = 1.4 m, Btor = 2 T, A = 4.3, Ip < 350 kA
Primary component measurements include:
In-vessel components Limiter surfaces, internal liner contour, internal coil current center
position, magnetic loops, etc. Vacuum Vessel
Shell surface, flange locations, port locations, support points, etc. Conventional coils
winding dimensions, current center locations, etc. Modular coils
winding dimensions, current center locations, flange locations, support points etc.
We also must measure the magnetic field surfaces, and reference these back to the coil set geometry
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Winding form tolerances Tolerances must be divided among various elements:
Baseline winding concept assumes winding form will be used as-is and not be custom shimmed or adjusted
Element Tolerance budget
Comment
Winding form +/- 0.01 in. Baseline on drawing
Copper cladding TBD Could be used to improve winding form tolerance if shims are allowed
Insulated conductor size +/- 0.01 in. Based on NEEWC input
VPI process TBD Assumed to be small, but not known
Assembly of coil in field period
+/- 0.020 in Adjusted to best fit, coil-to-coil with custom shims
Assembly of field periods +/- 0.020 in Adjusted to best fit with custom shims
Total tolerance +/- 0.06 in.
(+/- 1.5 mm)
Minimum value, may be relaxed according to location around winding
Winding
Winding form
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When do we make the measurements?
< R0 > = 1.4 m, Btor = 2 T, A = 4.3, Ip < 350 kA
During component fabrication e.g. Mod coil winding form inspection at vendor site
During component subassembly e.g. Individual conductor location on modular coils during winding,
net current center estimate for completed coil, etc.
During field period assembly e.g. measure flanges to determine required shim dimensions
between coils in a 3 coil pack, track the 3-coil assembly position as it is maneuvered over the vacuum vessel
During final assembly e.g. determine shim dimensions for mod coil flange connections, VV
spacer dimensions, port locations, etc.
And keep track of everything during machine operation
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We need to track the mod coil location during field period assembly and locate the ports
PortExtension
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How do we take the measurements?
< R0 > = 1.4 m, Btor = 2 T, A = 4.3, Ip < 350 kA
We need one or more metrology systems that include:
Measurement instruments These could include portable CMMs, such as a FARO arm, a laser tracker, a laser scanner, theodolites, etc. and would include any data acquisition hardware or computers needed to record data from the measurement instruments
Measurement software This would include the software needed to manipulate the measured data and perform optimization and best fit calculations.
Measurement standards This would include any calibration equipment or standards needed to maintain and verify accuracy of the instruments.
Measurement targets and monuments This would include the set of tooling balls, reference marks, holes, countersinks or other features required on the various components to establish the frame of reference for transferring data between measurement sets or for establishing the rigid body location of an object relative to other objects.
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How do we take the measurements? (2)
Scanning laser that attaches to 7-axis Faro arm (PPPL has one)
Integrated video camera takes points along scanned line @ 23,000 points/sec
Software determines part profile along line, “paints” image on CRT for operator and compares directly to CAD surface data
Accuracy is a function of the Faro arm only: ~ .003” for 6 foot arm, < .001” for 4 foot arm.
One interesting system is from 3D Scanners (http://www.3dscanners.com/)
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How do we take the measurements? (3)
NSTX has targets on vacuum vessel that can be seen from inside or outside
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How do we correlate to CAD data?
This is major QA issue
Most systems have this capability built into software
We also need optimization software to “best-fit” part contours and features with theoretical part, and correlate targets/monuments with global coordinate system
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Maybe we need a measurement matrix
Think through the fab/assy/operating steps List what needs to be measured, when, and how
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Some issues
Accuracy of measurements vs speed Can we take our measurement system to
vendors to verify their measurements? Distortion of parts during assembly or during
operation (moves the targets/monuments relative to each other and part)
Targets disappear Comparison of measurements to CAD data Optimization / “best fit” of part to data How / when do we measure magnetic surfaces? $$$$
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What do we do next?
Form a task force to:
Develop measurement matrix for all components (what, when, how) with help of WBS managers
Determine best set of tools (hardware/software)
Develop plan for any needed R&D
Work with WBS managers to determine type and locations of targets/monuments that will provide continuity of measurements throughout fabrication/assembly/operation phases
Data needed soon for modular coils and vacuum vessel!