Jacks and wave-guide couplers for Linac4, meeting 8/9 March 2011 at RRCAT, Indore, India

1. Introductory presentation by F. Gerigk
2. Jacks
3. Wave-guide coupler

1. Introduction

The possibility of producing the Linac4 jacks and wave-guide couplers was discussed and the construction details were discussed on the specification drawings. It is likely that the jacks can be produced at the "Indo-German Tool Room", a company which has already produced all of the LHC jacks. The wave-guide couplers would be produced directly at RRCAT, with the support of local sub-contractors. P.D. Gupta, the director of RRCAT was very supportive and is ready to give a certain priority to this project.

2. Jacks

A discussion was held with C.S. Sharma, the director of the "Indo-German Tool Room", a local company in Indore, which would produce the jacks.

Questions and answers and actions:

action institute/person status/result completed
clarify which pieces are commercially procured CERN, F. Gerigk done see Figure 1,2 2011-03-22
Can AL 6060 be replaced with 6063 CERN, F. Gerigk done yes 2011-03-22
Propose a replacement for AL 6082 IGTR, C.S. Sharma done 6082 can be procured in India 2011-03-25
Piece No.4: can surface hardened (with electroless Nickel plating) EN19 be used, as it was done for the LHC jacks? CERN, F. Gerigk confirmed  
Prepare delivery of commercial pieces for a pre-series of 3 CERN done ready for shipping 2011-03-22
Replace any plastic pieces with viton CERN pending  

*Figure 1:* commercial pieces of the jacks: alignment mechanism + bearings

*Figure 2:* pieces of the jacks: commercial pieces are encircled

3. Wave-guide Coupler

During the visit a prototype wave-guide coupler was shown, which was constructed according to the previous design of the Linac4 couplers. The overall impression was very good, but the piece still needs to be cleaned and vacuum tested.

The revised design was discussed and the following questions need to be clarified:

action institute/person status/result completed
send drawings of the electrode used for copper plating at CERN CERN done SPLACDTW0010.pdf, Cuivrage_T_guide_donde.pdf, L4-COOPERINGT.pdf, Tooling, picture 1, picture 4  
describe machining procedure for flange surfaces, which carry Helicoflex joints CERN done the surfaces are first fine machined and then finished by hand with scotch brite in the direction of the joints 2011-03-22
Can TIG welding be used instead of EBW for the race-track shaped welding of the coupling iris? CERN yes, but the surfaces of the flanges need to be fine-machined after the weldings. The process needs to be verified on a prototype. 2011-03-22
Can 316 L be used for the flanges instead of 316 LN? CERN done no, 316 LN is mandatory, CERN will send the flange material 2011-03-22
Should we consider to make 2 prototypes: i) according to drawings with bent sheets, ii) one with 4 welds CERN done version i) should be retained because this makes it easier to have vacuum tight welds and it minimises the risk of trapping chemicals (from the Cu plating process) in small volumes. 2011-03-22
Which pieces can be sent by CERN? CERN done CERN will send all raw material 2011-03-22
Can the tolerances of the interior length and height be increased from -+ 0.5 mm to -+ 0.7 mm? CERN done this might be acceptable for the interior but not for the flanges, the difficulty is how to do the welding of the large wave-guide flange when the tolerances are relaxed on the interior. For the time being we keep these tolerances and see what can be achieved on the prototype. 2011-03-22
Are the long weldings on the bent pieces done from the inside? Can these be done with 5 mm penetration from the inside + a closing weld (1 mm) from the outside? CERN done at CERN these welds were done as plasma welds with full penetration from the outside. Closing welds should not be used because they still carry a risk to develop small volumes which may trap chemicals from the Cu plating process. 2011-03-22
Can RRCAT use plasma welding? RRCAT done RRCAT is considering to procure the equipment 2011-03-25
Is it reasonable to first do all port weldings, then the large L-shaped pieces, and then the fine machining of the flanges? CERN done yes, this is the preferred procedure 2011-03-23
Are the welds on the circular flanges done with or without filler? CERN done welds were done at CERN without filler 2011-03-23
Provide documents for cleaning procedures, which are mentioned in the drawings CERN done  
Are the thin welds (3 mm) done from the outside? CERN done yes, full penetration from the outside 2011-03-23
Description of welding parameters CERN done
* For vacuum applications we can only accept full-penetration welds.
* For 6 mm thick steel sheets, the only techniques which are suitable are plasma welding (PW) or electron beam welding (EBW).
* At CERN these thick welds have been done via EBW, so we cannot give any advice on parameters for plasma welding.
* The plasma welding equipment at CERN has evolved over many years and comes from a mixture of suppliers, and it will not be very helpful to you if we give you this list.
* The process of plasma welding is apparently very delicate and finding the correct welding parameters is a process that has to be developed for each type of weld. The parameters will also depend on the type of equipment which you have available. At CERN the welders who do plasma welds are regularly sent to training sessions, because apparently it is a very specialised operation that cannot be done by someone who is only familiar with TIG welding.
* If RRCAT considers to procure plasma welding equipment, then also a specialist is needed to handle the equipment.
* Another option would be if you find a subcontractor who can do either EBW or PW.

-- FrankGerigk - 22-Mar-2011

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf Cuivrage_T_guide_donde.pdf r1 manage 78.6 K 2011-04-12 - 19:51 FrankGerigk  
PDFpdf Gerigk-CERN-Indore.pdf r1 manage 876.2 K 2011-03-22 - 10:44 FrankGerigk  
JPEGjpg Jacks_01.jpg r1 manage 229.2 K 2011-03-22 - 10:58 FrankGerigk  
PDFpdf L4-COOPERINGT.pdf r1 manage 40.4 K 2011-04-12 - 19:51 FrankGerigk  
JPEGjpg Outillage_cuivrage-2.jpg r1 manage 70.6 K 2011-04-12 - 19:52 FrankGerigk  
JPEGjpg Picture_001.jpg r1 manage 398.3 K 2011-04-12 - 19:53 FrankGerigk  
JPEGjpg Picture_003a.jpg r1 manage 449.5 K 2011-04-12 - 19:54 FrankGerigk  
JPEGjpg Picture_004b.jpg r1 manage 445.5 K 2011-04-12 - 19:54 FrankGerigk  
PDFpdf SPLACDTW0010.pdf r1 manage 151.8 K 2011-04-12 - 19:50 FrankGerigk  
JPEGjpg photo.JPG r1 manage 873.6 K 2011-03-22 - 10:52 FrankGerigk  
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Topic revision: r5 - 2011-05-20 - FrankGerigk
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