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PACMAN, CERN, Geneva, 20-22 March 2017
Metrology toolbox
for
mechanical design & alignment
(Alain LESTRADE, Synchrotron SOLEIL)
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PACMAN, CERN, Geneva, 20-22 March 2017
SOLEIL Project
Synchrotron source: 2.75 GeV SR: ø110m
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PACMAN, CERN, Geneva, 20-22 March 2017
SOLEIL Project
Ex: phase contrast microtomography on PSICHE beamline
of a 320M y/o grasshopper hosting an acarid
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Magnet & magnetic bench Stages for scanning Opto-mechanical component
PACMAN, CERN, Geneva, 20-22 March 2017
Frame of the lecture
Full SR alignment procedure from the rotating coil
to the beam based alignment
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Practical tools for Metrology & Mechanical engineering in the field of the instrumentation
Examples are oriented “Synchrotron facility”
Metrology toolbox
PACMAN, CERN, Geneva, 20-22 March 2017
Nothing is specially new in this toolbox
It is just a formalization of well known rules of good use and good design,
a way to a global point of view, to reorganize.
Metrology toolbox: a “checklist” which allows a
Spatial layout analysis of dimensional measurement systems
- Mechanical units under beam
- Metrology setup for their qualification
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PACMAN, CERN, Geneva, 20-22 March 2017
Dimensional Metrology
Measure Time
SpaceMechanics
Means: Point of view:
Stability Time Constant
Vibrations
Sensors & instruments:
Random & Bias Errors
Mechanical units:
Random & Bias Errors
Degrees of freedom
Metrology loop
Lever arms & effective length
Error Separation Layout
Affine & vector spaces
Sensitive direction
Differential measurements
Not exhaustive6
PACMAN, CERN, Geneva, 20-22 March 2017
The main question
• How to link these notions from each other in order to analyze stability,
accuracy, etc, in a qualitative (& quantitative) way?
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PACMAN, CERN, Geneva, 20-22 March 2017
Measure Time
SpaceMechanics
Means: Point of view:
Metrology loop
Lever arms
Error Separation Layout
Not exhaustive
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PACMAN, CERN, Geneva, 20-22 March 2017
Metrology loopMeasure Time
SpaceMechanics
CMM (Hennebelle, ENSAM)
Metrology loop
Sensor
𝑇𝑍
Object
𝑇𝑋
𝑇𝑌
Support
Wobble, straightness
& backlash
Encoders errors
Encoder errors
?
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• Any system dedicated to positioning or requiring a positioning operation, consists of a stack of mechanical parts and/or of sensors, the metrology loop.
𝑆𝑋
Support 𝑆𝑌
𝑆𝑍
Sensor
Measuring loop
Kinematic loop
PACMAN, CERN, Geneva, 20-22 March 2017
Metrology loop: partial dissociationMeasure Time
SpaceMechanics
(Hennebelle, ENSAM)
h
W
𝑒𝑥=W.h
B
𝑇𝑌
h
Fixed
𝑇𝑌
W
B
Movable
Support
Sen
sor
B: backlash
W: wobble
h: lever arm
e: error
Encoder
Wobble
rotation axis
X
𝑇𝑋
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PACMAN, CERN, Geneva, 20-22 March 2017
Each point of interest for the analysis
Quantitatively:
the corresponding transfer function:
sin-cos error, random error,
optics function, torsor, etc.
Qualitatively:
the sources of errors
Sources of errors Transfer function
….
….
….
Metrology loop
Measure Time
SpaceMechanics
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Lever arms & effective length
PACMAN, CERN, Geneva, 20-22 March 2017
Measure Time
SpaceMechanics
The effective length (EL) is the smaller lever arm on the metrology loop
Lever arms applied to parasitic rotation (sine-cosine errors)
𝐸𝐿 ≈ 10𝑚𝑚
𝑀𝑒𝑐ℎ. 𝑐𝑜𝑛𝑡𝑎𝑐𝑡 ≈ 80𝑚𝑚
4-quad cellDiode
Support
Contact 80mm
Body
Sensor 10mm
𝑔
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W
(Hennebelle, ENSAM)
ℎ𝑧
ℎ𝑦
ℎ𝑖: Encoder / object (sample)
ℎ𝑥
PACMAN, CERN, Geneva, 20-22 March 2017
Error Separation LayoutMeasure Time
SpaceMechanics
1st reversal
2nd reversal
Reversal of a
centring system
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Multiprobe method for
rotation stage SOC
n-points rotation of a coil
ESLCone
𝑇𝑟𝑖𝑏𝑎𝑐𝑘
Target
𝑃1
𝑃2
𝑃1
𝑃2
Monument𝑖 =𝑙1 ± 𝑙2
2
𝑒 =𝑙1 ∓ 𝑙2
2
ESL
Sphere
To collect both measurement & bias error:
offset, excentricity, SOC, cylinder circularity, etc.
PACMAN, CERN, Geneva, 20-22 March 2017
Measure Time
SpaceMechanics
Means: Point of view:
Stability Time Constant
Not exhaustive
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• The stability of the set “Instrument-Object” should be better than the measurement accuracy target .
• STC is the acceptable duration t during which we do not want less than a parasitic displacement
quantity d :
• STC = (d, t)
• Whatever the origin of the disturbance of the system: mechanical, electronic, etc.
PACMAN, CERN, Geneva, 20-22 March 2017
Stability Time Constant
t (s)
Meas. Duration t
Meas. Accuracy δm
STC
Parasitic slow drift
Max. displ. d
d (µm)
Measure Time
SpaceMechanics
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PACMAN, CERN, Geneva, 20-22 March 2017
Stability Time Constant
• Differential DOF * has to be considered.
• Theodolite: 3.10-4deg accuracy t=4h measurement duration:
Measure Time
SpaceMechanics
* DOF: Degrees OF Freedom
Metrology loop
in 𝑅𝑧 stability
𝑅𝑧 object
𝑅𝑧 intrument
𝑺𝑻𝑪𝑹𝒛= (<3.10-4deg; 4h)
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Fixed
Floor
Tripod
Theodolite
Stand
4ℎ
4ℎ
4ℎ
4ℎ
Mirror
Ref. m
easur.
30′Ref.
meas.30′
Wall
Metrology loops in Storage Ring
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Physics (BBA): STC=(1µm;run)
Alignment: STC=(15µm;survey)
Mechanics Stability:
STC=(15µm;2 surveys)
PACMAN, CERN, Geneva, 20-22 March 2017
Qpole
BPM
GirderStand
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Metrology loop and HLS at NANOSCOPIUM
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BPM1NanoProbe
BPM2 M1Secondary Source
OH5 hutchhallSR tunnelInsertion
device
𝑀1 𝑆𝑆SP
𝑴𝒗(z)
HLS+water
BPMs+beam
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M1 transfer function
𝑴𝒗
𝑴𝒗
HLS+water
M1+beam
HLS+water
SS+beam
PACMAN, CERN, Geneva, 20-22 March 2017
Case study: The Qpole Alignment at SOLEIL
• The following steps are applied:
– Magnetic axis detection
– Fiducialization
– Mechanical alignment on girder
– Checking survey per girder Fiducials
1 X Shims
4 Z Shims
e-
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Case study: The Qpole Alignment at SOLEIL
ESL
ESL
Tool mag axis
Tool stand
Pin
Bench
Tool ext face
Coil rotation axis
Coil mag axis
Ball bearings
Coil stand
months
months
months
months
𝑚𝑛
𝑚𝑛
𝑝𝑒𝑟𝑖𝑜𝑑𝑖𝑐𝑖𝑡𝑦
𝐶𝑀𝑀Pin
Coil mag axis
• The bench for magnetic measurements, calibration tool:
– Link the coil axis to the bench in order to avoid STC = (few µm,months)
• A permanent Qpole tool with 8 faces
• The tool is accurately measured
PACMAN, CERN, Geneva, 20-22 March 2017
Pin
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PACMAN, CERN, Geneva, 20-22 March 2017
Case study: Qpole zero detection
– Each Qpole is measured by the bench: differential measurements
– A set of shims are chosen for having the zero on the axis of the coil
– STC = (few µm, months) for the whole metrology loop
– The weak point is the pin STC = (few µm, months):
– 200 times in contact with 300-500kg!
ESL
Pin
Bench
Coil rotation axis
Coil mag axis
Ball bearings
Coil stand
months
months
months
months
𝑚𝑛
Qpole mag axis
Shim
Pin
months
months
months
Qpole yoke
months
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PACMAN, CERN, Geneva, 20-22 March 2017
Case study: The Qpole Alignment at SOLEIL
• Fiducialization:
– Qpole Comparator: 4 electronic dial gages + 1 inclinometer
– Contact on the coil support in rotation
– Error Separation Layout: for X direction & tilt, not for Z!
– STC = (10µm,30mn) in X thanks to the ESL, STC = (10µm,∞) in Z
– The metrology loop does not include the bench!
Reversal
Qpole comparator
Hz ESLCoil rotation axis
Coil mag axis
Dial gauges zero 1
Inox structure
Dial gauges zero 2
Fiducials
𝑚𝑛
𝑚𝑛
𝑚𝑛
ESL
𝑚𝑜𝑛𝑡ℎ𝑠
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PACMAN, CERN, Geneva, 20-22 March 2017
Laser ecartometry of Qpoles on a girder :
– Qpoles are mechanically aligned by the contact of their shims with the girder
references: X pin & Z surface
– ESL: reversal of the laser position WR to the girder
– Beam stability is easy: STC = (few µm,2mn)
Case study: The Qpole Alignment at SOLEIL
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PACMAN, CERN, Geneva, 20-22 March 2017
Case study: The Qpole Alignment at SOLEIL
Ecart-type: XCM (µm) ZCM (µm) TiltCM (mm/m)
per girder: 15.2 10.6 0.053
for the orbit: 14 9 0.053
Global loop
Girder pins alignment
Zero detection
Fiducialization
Laser ecartometry
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PACMAN, CERN, Geneva, 20-22 March 2017
Metrology report
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PACMAN, CERN, Geneva, 20-22 March 2017
Metrology report: sensitive direction
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PACMAN, CERN, Geneva, 20-22 March 2017
Metrology report: metrology loop
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PACMAN, CERN, Geneva, 20-22 March 2017
Metrology report: STC & lever arms
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PACMAN, CERN, Geneva, 20-22 March 2017
Thank you for your attention!
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