1. Mechanical design and tests of the new X-band flange
EDMS №
Mechanical design and tests
of the new X-band flange
A. Samochkine

2. Pre-series production
Contents
Aim and Testing
Requirements
Features in 3D model
Drawings
Tolerances
Configurations
Pre-series production
Mechanical test results and comparison with simulations
Mechanical test results
Proposal on configuration
Knife  “Squared shape"
Gasket  1 mm thick
Ref. :
CLIAVACU0189 ST

3. International Universal X-Band Flange (IUWR90)
Mechanical design aim
Develop WR90 common RF vacuum flange design in collaboration with different laboratories.
PM Testing
Tests on gaskets
Assembly and disassembly;
Leak tightness tests;
Mechanical measurements;
Baking.

4. Set of required flange features
(Recommendation of committee. KEK collaboration meeting - May 2012)
1. Rectangular flange with 8 bolts
2. Precision outside dimensions for easy assembly verification
3. Grooves from gasket to outside of flange for leak test
4. Corners of gasket seat to be made circular for ease of gasket removal
5. No guide pins, study external alignment jig
6. Internal radius on corners of flange gasket knife to be made a big as reasonably possible
7. Simple rectangular copper gasket 1mm thick, completely annealed
8. Threaded hole on flange side for mounting
9. Minimize length of the RF part of flange (in case if used without copper plating).
10. Consider brazed side with round pockets near waveguide edges (like in KEK flange or Haimson's WR62).

5. Features in 3D model
1. Rectangular flange with 8 bolts
2. Precision outside dimensions for easy assembly verification
3. Grooves from gasket to outside of flange for leak test
4. Corners of gasket seat to be made circular for ease of gasket removal
5. No guide pins, study external alignment jig
6. Internal radius on corners of flange gasket knife to be made a big as reasonably possible
7. Simple rectangular copper gasket 1mm thick, completely annealed
8. Threaded hole on flange side for mounting
9. Minimize length of the RF part of flange (in case if used without copper plating).
10. Consider brazed side with round pockets near waveguide edges (like in KEK flange or Haimson's WR62). 1 3
2, 5 4 6 7 8 9 10

6. Flange drawing (CLIAVACU0189)

7. 12 versions Design iterations 2 main knife parameters: 0.5 mm 0.75 mm
1. Flat knife edge width
0.5 mm
0.75 mm
1 mm
2. Gasket compression
0.2 mm
0.3 mm
0.4 mm 12
versions

8. Flange drawing (CLIAVACU0189)
Reference  External surfaces

9. Machining dimensions before copper coating
Requirement 9
Machining dimensions before copper coating

10. Gasket drawings (CLIAVACU0190 & …191)
CLIAVACU0191, Interference fit
CLIAVACU0190, clearance fit 20
-0.02
-0.04
+0.03
+0.01
32.7

11. Pre-series - procurement of 48 flanges
(12 configurations x 2 sets of 2 flanges each);     - 50 gaskets with a clearance fit and 50 with interference fit
First series of 150 sets of the most successful configuration chosen through the pre-series phase.

12. Test on gasket compression (EDMS 1289259)
Testing
Test on gasket compression (EDMS )
Dimensional control of gaskets after use (EDMS )
Thermal test of copper coating quality
920 °C
250 °C (according to ASTM B571-97)
Test on multiple usage of flange
Leak test (EDMS )
High power test at SLAC

13. Test on gasket compression (EDMS N1289259) [part1]

14. Conclusions after gasket compression test
Two gaskets were inspected after use in assemblies of IUWR90 flanges.
The expansion of gasket into waveguide zone observed in case of flanges “4 – 4 1EM” is about 0.15 mm all around.
The expansion of gasket into waveguide zone observed in case of flanges “9 – 9 1EM” is about 0.1 mm all around.
The vacuum sealing is equally successful in both cases.
The use of flanges “9 – 9 1EM” is preferable because of smaller expansion into RF zone.

15. Gasket deformations after use (EDMS 1303470) [part2]
• 10 different flange pairs of different designs (variation of “pressure width” “a” and “pressure depth” “b)
• Every gasket has same initial dimensions
• Assemblies are screwed together until stainless steel parts are in contact
• After 48 hours, assemblies are dismounted and the deformed gaskets openings were measured.
 The aim is to assess how deep the gasket penetrates into RF volume after mounting as a function of “a” and “b”
Openings measured in two ways:
X₀ as reference opening
Flange
X₁ as initial verification
New gasket
Tested gasket
X as final opening
Ceramic gauge block set
Optical Stereo microscope
-> accuracy depends on user: ~0.02 mm
suitable and fast way
of assessing the opening
new gaskets
tested gaskets and flanges
Measurements by M. Rissanen

16. Conclusions after dimensional control of used gaskets
a \ b
0.25
0.30
0.35
0.40
0.50
0.227 X
0.124
0.079
0.75
0.280
0.224
0.114
1.00
0.295
0.210
0.214
0.143
The expansion of gasket into waveguide into the RF volume for design 12
(highest “a” and smallest “b“) is biggest mm
The expansion of gasket into waveguide into the RF volume for design 7
(smallest “a” and biggest “b“) is smallest mm
For further reduction of the protrusion length “a” should be further decreased below 0.5 and “b” should be further increased above 0.4. The limit is represented only by the leak tightness, which is yet to be assessed.

17. Thermal test of copper coating quality
The copper plating on three flanges CLICAVACU0027 where tested according to the ATMS procedure “B TEST D’ADHESION INOX CUIVRE” chapter 9, Heat-Quench Test.
The procedure or testing the adhesion of copper coating to stainless steel:
heat up the copper coated stainless steel part to 250 °C and keep for 10 minutes (for being sure the whole part has uniform temperature)
rapid cooling in demineralised water at room temperature (20 °C).
If the copper plating doesn’t crack or start to peel of the coating is good.
Equipment:
The furnace used was a VENTICELL 222 with air filter class S DIN and a forced ventilation.
Brazing cycle was used to see if the copper coated flange sustains the heating (baking).
The good copper adhesion is proved by both tests.

18. Test on multiple usage of fully copper coated flange
The goal for these tests is to learn how the copper coating of the knife zone of the RF vacuum flange is affected during several assemblies with gaskets. The flange used was CLIAVACU0189 version 1, 6 and 12 The gaskets used were CLIAVACU0191 and CLIAVACU0190.
First all combinations where assembled and studied. The combination with the biggest deformation on the gasket was chosen for the tests to be repeated. The greater the deformation of the gasket is, the bigger the impact on the knife was expected. After repeated assemblies more and more scratches appear.
Small additional scratches appear after each assembly. The deformation of the gasket is also the biggest in shown zone.
Assembled 4 times
Assembled 9 times
Inspection by F. Smeds

19. Conclusions after several assemblies
The whole flange copper coating is more cost effective.
The micro scratches observed on the knife surface after ten assemblies are negligible. That must be confirmed by deeper analysis (measurements). Most probably the annealed gasket will fill the cracks and scratches created during previous assembly.
Proposal for next steps
Vacuum leak tightness tests with plated flanges and repeated assemblies.
SEM pictures for deeper knowledge on the coating and the scratches.

20. Simulation of the gasket compression
The aim:
Evaluate the deformations of the gasket compressed between two flanges
Evaluate the torque required to tighten the screws
12 gasket versions with varying flange knife dimensions
FLANGE
GASKET

21. Simulation of the gasket compression
Gasket deformation under compression
Version
3D model (µm)
Exp. measurements (µm) 1
188
114 (-39 %) 6
300
210 (-30 %) 7 86
79 (-8 %) 12
373
295 (-21 %)
Study by L. Kortelainen

22. Sub-assemblies for high power test at SLAC
CLIATLRF0128
CLIATLRF0129
Inlet inspection of 8 units of IUX Test setup assembly. (EDMS )

23. Sub-assemblies for high power test

24. Leak test (EDMS # 1290515) Leak detector type: ASM 121 h
Reference leak rate: 6.2±15% ×10⁻⁷ mbar•l/s Minimum detectable leak rate: 2×10⁻¹⁰ mbar•l/s
Tracer gas: Helium 99%
System pressure: 1×10⁻³ mbar
Test temperature: ̊C
Max. measured leak rate: Version 12/12 1EM & 1/1 1EM: 4.0 x 10⁻¹⁰ mbar•l/s Version 4/4 1EM & 9/9 1EM: 7.0 x 10⁻¹⁰ mbar•l/s

25. Shipping to SLAC for high power test
24-May-2013

26. From PM fabrication, inspection and tests:
Conclusions
From PM fabrication, inspection and tests:
Fully coated flange is recommended
Version 7 is recommended as it gives the smallest deformation
Waiting for High Power test results at SLAC to launch the series production

27. SPARE SLIDES

28. Alignment & fixation for example Clamping tool. Schematic view.
Specially sized cantilever clamp with cylindrical grips to be designed. The self-adjustment in both, horizontal and vertical directions, as well as fixation before and during the bolts tightening is provided by pushing against the V-shaped grooves.

29. Knife  “Improved" & optimized
Two configurations
Option 1
Option 2
Knife  “Squared shape"
Gasket  1 mm thick
Knife  “Improved" & optimized
Gasket  2 mm thick

30. Minor friction keeps the gasket in place in any angular position
Gasket retention
Minor friction keeps the gasket in place in any angular position