1. Crab Cavities: In-house Production Extremities
R. Claret, M. Garlaschè
…J-P. Brachet, P. Freijedo, L. Giordanino, R. Leuxe, L. Prever-Loiri, T. Tardy…

2. Extremities TO DO List: 4x Extremities HOM & FPC 2x Extremities Beam
1x Extruded extremity Pick-up
NbTi Plate
316LN 3Df
Nb Sheet
Nb Plate
ر0.1
Ref. LHCACFCA0014
Ref. LHCACFCA0001

3. Extremities TO DO List: 4x Extremities HOM & FPC 2x Extremities Beam
1x Extruded extremity Pick-up
Interfacing with other Jobs. WHERE?
F.E. Welds
Shaping: Thickness/Shape & Length
Collar
Ref. LHCACFCA0001

4. Extremities: Critical points
thckDESIGN=3mm
#1) Precision of Nb Sheet for Brazed subassembly
WHY?
Usual tolerances (DIN & DOUT) =0.01
+0.5
+0.5
ACTIONS:
Starting with 4mm Nb sheet, instead of 3mm.
Remachining minimum to comply with tolerance
Ref. LHCACFCA0001

5. Extremities: Critical points
#2) Size & Thickness of interface to cavity
WHY? addressable only after feedback from shaping
+0.5mm
+~0.5mm
+>0.5mm
ACTIONS:
Launch rough components
Overthickness on Nb plate (& sheet)
Only Collar launched following forming
CASE Smaller extrusion
CASE Bigger extrusion
Ref. LHCACFCA0001

6. Extremities: Critical points
#3) Assembly Steps: Extremities VS. EB Welding
Matter being addressed
Change welding sequence on lunette
Adding one intermediate collar 1 2

7. Extremities: Critical points
#4) Nb Extrusion
WHY?
On Collar addressable only after feedback from shaping
ACTIONS: Not deemed highly critical
Eventual test, Intermediate extrusion tool

8. Planning Extremities End April WK3 End July 2016 DESIGN MANUF.
Long Delay Mat. ordered
End July
CERN
Extremities
2016
Final Welding
Tool Weld Tests
Tooling for
weld Test
Tool Weld
Tool Extrusion
Weld Qualif
Brazing
Welding (rough parts)
Interface Collar
Remach. Rough parts
(Nb, NbTi, Flange)
Extrusion
Shaping Input:
Thickness & Length of extremities
Extremity Design ready < WK3
DESIGN
Launch:
Cimblot
Ebauche brides
Nb & NbTi Coronas
Pieces for Qualif
MANUF.
Overlength and overthickness on Nb corona
30.03 pour HOM/FPC
06.05 pour Diabolo
ASSEMBLY

9. Conclusion
Foreseen deadline not critical for Extremities, provided input is obtained on time
Watch OUT for deadlines needed on:
Design of extremities Deadline
Shaping: dimension and wall thickness of interfaces
Extremity weldability (geometrical access for E.B) on Lunette may change requirements on welding sequence