1. Réunion service Instrumentation Activités CMS-Traces
Nick Lumb
Institut de Physique Nucléaire de Lyon
22/02/2018

2. Laser scan results +3.5mm -3.5mm +3.5mm -3.5mm -0.4mm +0.4mm +0.4mm

3. 1 Final machining Brand new large area 5 axis CNC machine
2S inserts: machined to correct level in Z, nipple, fixation holes
PS inserts: machining to correct level in Z (flush with CF skin), fixation holes

4. Measurement of insert positions
Romer measurement arm with φ3mm ruby tip
Prototype constrained by vacuum on pre-machined platform
Points compared directly with imported CAD model of ideal object

5. XY positions (screw holes)
Mean
-0.004
RMS
0.013
Mean
0.014
RMS
0.012
Mean
0.000
RMS
0.005
Mean
0.003
RMS
0.010
Well within spec. of +/-50 microns

6. 2S inserts Z positions: Z+ side (module mounting surfaces)
Mean
3.851
RMS
0.014
Outliers correspond to 9 inserts situated above the ‘step’
Binned values correspond to height above arbitrary reference plane defined from calibration measurements of support platform
Module mounting surfaces aligned with RMS of 14 microns!

7. 2S inserts Z positions: Z- side (module mounting surfaces)
Mean
RMS
0.015
~Same RMS for Z- side
Distance between mounting surfaces on the two sides of the prototype should be difference between the means of the distributions: – ( ) = 16.66
Target was /- 0.05mm
There are two complicating factors:
Mistake during CNC programming: assumed 10mm sandwich thickness instead of 9.6!
When prototype is turned to measure the second side, link with measurements of first side is lost, introducing a possible offset

8. Next: thermal measurements!
N. Lumb