Panel components and construction Roma Pavia Saclay CERN MM mechanics meeting, H. Danielsson CERN
Vacuum bag method in Roma 1 Roma 1 / 14-4-2014 5 panelsfor M2 In the twosteps the gluedpcbis on the granite table: thisprovides the goodplanarity. The thicknessis 10.949 ± 16 μm in panels 1,3,4,5. Panel 2 isexpected 0.16 mm thickerbecause of a thickerpcbused.
Two more panels 60 x 100 cm²werepreparedto test the effectof the delay 6 h vs 24 h • in the twostepsapproach. Betterresults are foundfor 24 hours. • To improve the correctthicknessalso in the frame regionsa last panel, 60 x 68 • cm² large and with 6 mm Al honeycomb, hasbeenbuiltwith slices of honeycomb inside the Al frame. • Results: • The method and the measurementsof the panels are reported in: • ATL-COM-MUON-2014-024 • Wedecidedtobuilt a full size SM1 withthistechniquebeforethis MMM Workshop but • wehad some delay in the procurementof the components.
As an alternative to the insertionof the honeycomb in the frame we are nowtesting the useof a stiffback inside the vacuum bag whilegluing the secondpanel. Thisshouldbettergarantee the samethickness in the frame and in the honeycombregion. A smallpanel 60 x 60 cm²isready and willbemeasuredMondayApril 14th.
Inserts placed with the Rasmasks tooling method in a previous stage l ε α Stiffback mounted with short reference pins (L=30mm - ø 16mm) to guide PCB STIFFBACK V shaped block to get precise and high repeatibility system L α Precision shims ε α ml, ε’ On the issue of panel assembly and detector assembly (Alan) If the assembly is done using long pins (let’s say more than 50mm long) than the error if the base of the pin is not flat in contact with the marble leads to an innaccuracy of more than 60 microns... and this is just the theory - we can add a good 20 microns operator error to that!! The case of a pin long of 100mm with a diameter of 10mm leads to 100 microns sway!!! ε’=L ε/l (for α small ) best case l=L (square) if L increases ε’ as well Therefore proposition MM mechanics meeting, H. Danielsson CERN
PLANS (CERN) • NSW1 • Glue the frame • Test gluing of the mesh on a test panel • Measure thickness • NSW2 • New stiff-back with low CTE • Possibly with foam • New gas inlet • Simplified frame pieces • Module 0 • Design started • FEM calculations stiff-back. The stiff-back is the key. MM mechanics meeting, H. Danielsson CERN
Assembly • NSW 1 • Stiff-back prototype for NSW2 and module 0 under construction • Material carbon fibre, honey comb core. Carbon fibre in closeouts MM mechanics meeting, H. Danielsson CERN
NSW 1 MM mechanics meeting, H. Danielsson CERN
Module 0 design MM mechanics meeting, H. Danielsson CERN
FEM Calculations of stiff-back (preliminary) • From experience low CTE required MM mechanics meeting, H. Danielsson CERN
Preliminary Results • 100 mm thickness • Max deflection 30-40 mm (center) • Weight 87kg • We are studying 200 mm thickness • Max deflection 20-30 mm (center) • Weight 120 kg (!) MM mechanics meeting, H. Danielsson CERN