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Review MQXFB: preparation for impregnation and impregnation
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Europe/Zurich
180/1-Y01 (CERN)
180/1-Y01
CERN
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10:25
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10:30
Technical outcome Poste 5: Splicing 5m
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10:30
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10:50
Technical Outcome Poste 6: perparation for impregnation 20mSpeaker: Susana Izquierdo Bermudez (CERN)
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10:50
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11:00
Decision on QH layout 10mSpeaker: Paolo Ferracin (CERN)
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11:00
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11:40
Impregnation Process 40mSpeaker: Attilio Milanese (CERN)
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11:40
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11:55
QA Documentation 15mSpeaker: Rosario Principe (CERN)
Minutes also available on EDMS @ 2273382
Attendees: Arnaud Devred (DGL), Paolo Ferracin (WP3 DWPL), Susana Izquierdo Bermudes (MQXFB WPE), Attilio Milanese (SL), Rosario Principe, Frederic Savary (WP11 WPL)0, José-Luis Rudeiros Fernandez.
1. Scope of the Review
Few months ago, due to a number of critical non-conformities during the MQXFB coil production, the MSC group decided to stop the coil fabrication and audit the manufacturing process in order to identify and implement the solutions required to reduce the risk level in the production. This activity, so called “deverminage”, interested the complete coil production cycle, involving the MQXFB QA team, the WPE and PE, and a number of stakeholder in the MSC LMF and MDT sections.
The analysis was performed reorganizing the production in 6 production stages: 1) spooling, 2) winding, 3) curing, 4) reaction, 5) splicing and 6) impregnation.
This specific meeting intends to present the status of art after few months of exercise and close the “deverminage” phase for the stage 6) impregnation.
2. Fabrication Procedure Preparation for Impregnation Poste 6
Susana Izquierdo (MQXFB WPE) presents the outcome of the debugging of the Fabrication Procedure Preparation for Impregnation Poste 6 EDMS 1726065, version 6.0. This version includes the feedback of the activity related to impregnation of coils 204, 003 and 205.
All the main technical points and improvements implemented in the fabrication procedure are reviewed during the meeting. Particular emphasis to:
- Insulation layers of the inner coil diameter;
- The repair technique of the wedge insulation at the outer layer after reaction;
- The repair technique of the wedge gaps with S2 glass;
- The S2 glass filling on the coil ends;
- The insulation of the coil to end saddle;
- Coil protection after reaction;
- Lateral rails;
- Bolting of the impregnation mould;
- Continuity checks;
- Filling material for the pole holes;
- The finishing operations;
- The hole patterns in the OL trace.
Few remarks and recommendations from the panel and attendees.
Concerning the repair technique of the wedge gaps with S2 glass, it is requested to analyse and compare the solution in the 11T fabrication procedure.
During the presentation of the adopted method for the coil protection after reaction, the issue of the clamping of the coil is raised. I t is asked to check and compare the MQXF procedure with the solutions adopted in the 11T fabrication procedure.
An issue related to the measurements of coil length and coil length history during assembly is also raised. Once again it is asked to compare the approach with the one used during the 11T coil production.
For the finishing operation, it is suggested to replace cutter by sand paper. A feedback on the dangers related to the use of a cutter at this phase of the production is given by the 11T WPL. This modification will be annotated on the fabrication procedure version 6.0 and implemented with appropriate pictorials in version 6.1.
A last recommendation concerns the use of new design of QH as soon as the VTaps are not installed. It is suggested to proceed to the purchasing of new design of QH asap.
3. Impregnation machine
Attilio Milanese (LMF SL and PE) presents the status of the art and the main improvements related to the impregnation machine and its use. To be considered that the machine was deeply renovated and today is based on a CERN developed system (hardware and software). This evolution was necessary to better respond to needs of the production and includes the feedback from the users. Future developments, to be operated after S197 completion, are also introduced.
The analysis of the cycle shows that the The temperature near the coil, recently measured, has good uniformity. Today some WIFI thermocouples are used to track the TCPole.
The remote monitoring and operation is in place, through Remote Desktop and all data are today stored and accessible in real time on Timber (CERN wide logging database).
A feedback of the exchange with FNAL and BNL is also presented (Dave Evans and Giorgio Ambrosio). This concerns few aspects including the mixing process and the analysis of the resin batches.
Finally, no critical non-conformities related to the impregnation machine and the cycle were observed. Neither on 11 T nor on MQXFB. The NC on GE-20 is not linked to the impregnation machine (erroneous assembly of mandrels). Furthermore, the related procedure (EDMS 2025156) is mature and common for 11 T and MQXFB.
Few remarks and recommendations from the panel and attendees.
At present two differences in the VPI process between 11 T and MQXF were noticed. The temperature of leak test, not very significant, and the difference in pressure. 2.5 bars for MQXF and 3.5 for 11 T. This is probably due to historical reasons, but it is recommended to check in order to have a better understanding. The issue cannot be rapidly solved, to be considered as an R&D common effort of MDT and LMF.
Concerning the Dave Evans’ comments, it is recommended to pursue the possibility of extracting samples from the mixer unit and to find a method to have chemical analysis of each resin batch to be compared with the results obtained by BNL and Fermi lab.
4. QA QC
Rosario Principe (QAS) provides the information concerning the status of the QA QC documentation related to the impregnation process stage 6.
- Fabrication Procedure (including MIP and follow-up files) ;
- Control procedure;
- Impregnation protocol and injection system manual;
- Competence matrix.
The fabrication procedure “Preparation for Impregnation” Poste 6 EDMS 1726065, version 6.0, was completely revised. In Engineering Check since Tue Nov-19, it will be commented and approved by Wed Nov-20. All modifications are also reflected in the related MIP and follow-up files.
The control procedure EDMS 2156666, version 3.0, is ready for approval too. No relevant changes were identified in this new version.
The same for the Impregnation protocol and injection system manual, version 4.0, EDMS 2025156. The latter is common to 11T and MQXFB.
Both documents will be released by Wed Nov-20.
The competence matrix was completely revised and released.
Nothing pending on Thu Nov-21. Nothing else to add on the QA side.
5. Outer layer quench heater for MQXFBP
Paolo Ferracin (WP03 DWPL) presented the draft of the document “HL-LHC management decision” concerning the Outer layer quench heater position in the MQXFBP2. Finally the MQXFBP2 coils will be fabricated with impregnated QH in the current baseline design.
The proposal is accepted, but the document needs to be iterated and revised in order to reconsider and explicit the differences between 11 T and MQXF magnets. These differences will be illustrate in “the rating of options” section in order to motivate the reasons of a different decision.
6. Conclusions
Although few aspects need to be better defined, nonetheless the review committee expressed global satisfaction for the work provided up to now. A substantial improvement can be observed in terms of quality of the documentation and work organization.
The presented procedures for Post 6 impregnation are considered mature, and ready for the production. For these production stage the “deverminage” can be considered closed and the production can restart, although all documents are continuously analyzed, discussed and updated.
It is agreed to proceed with internal quench heaters, as described in the fabrication procedure version 6.0.
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