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

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

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

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

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

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!

2S inserts Z positions: Z- side (module mounting surfaces) Mean -12.805 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: 3.851 – (-12.805) = 16.66 Target was 16.44 +/- 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

Next: thermal measurements! N. Lumb