Coil head locking during RHT Work Group on

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Coil head locking during RHT Work Group on Methods and Procedures F. Lackner, July

Coil head locking during RHT Work Group on Methods and Procedures F. Lackner, July 5 th, 2019 logo area

Content § Observed NC during RHT of CR 204 § Indentification of similar observations

Content § Observed NC during RHT of CR 204 § Indentification of similar observations during the MQXFB coil fabrication § QC procedure, current steps § How to reduce risks (Reproducability, fatigue, friction) § Further improvements § Alternative by removing clamp ? § Proposal § Conclusion logo area F. Lackner, 1 st Work Group Meeting on Methods and Procedures 2

NC of coil CR 204: 6. Plastic deformation: Guide screws (both extremities !), large

NC of coil CR 204: 6. Plastic deformation: Guide screws (both extremities !), large thermal expansion and stress 5. Surface damage & cable deformation: surface damage on cable, insufficient length of mica. Lead end 7. Friction marks: pole and centring pin 1. Damage: strand/cable 2. Damage: strand/cable 3. Large between Vamas block and end-spacer due to wrong positioning prior RHT. logo area 4. Positioning error: Vamas block to filler wegde contact at pos. 100 mm F. Lackner, 1 st Work Group Meeting on Methods and Procedures

History based on available information: Coil id Visual observation from picture Screw position w.

History based on available information: Coil id Visual observation from picture Screw position w. r. to end spacer CR 101 Deformed screw NCS no contact CR 102 conform in contact CR 103 NC RHT in contact, change of screw length CR 104 conform in contact, change of screw length CR 105 - no info, change of screw length CR 106 NC winding no info CR 107 conform in contact CR 108 conform in contact, change of screw length CR 109 conform, NC ceramic coating in contact, change of screw length CR 201 conform, NC ceramic coating in contact CR 202 conform, NC ceramic coating in contact CR 203 conform, NC ceramic coating in contact CR 204 NC – RHT & Deformed screw NC & NCS no contact CR 101 CR 103, long screws ? CR 204 F. Lackner, 1 st Work Group Meeting on Methods and Procedures

From procedure, EDMS 1726017 R 4: 6. 12 Mise en place des outils de

From procedure, EDMS 1726017 R 4: 6. 12 Mise en place des outils de fixation des têtes Mettre en place dans la rainure, le 1 er outillage côté opposé connexion (RS) : LHCMQXFT 0643. Mettre en place dans la rainure, le 2ème outillage côté connexion (LS) : LHCMQXFT 0643. 7. 3 Centrage de la bobine Approcher l’ensemble au-dessus du moule de réaction. Se centrer par rapport au côté Connexions (LS), le bout du dernier espaceur de tête doit être aligné avec le bloc mandrin LHCMQXFT 061415001 (16001 pour l’outil n° 2). La précision de mise en place est de +/- 1 mm ! ATTENTION : VEILLEZ à ce que le dernier espaceur de tête (couche interne ou couche externe) ne dépasse pas du premier bloc mandrin LHCMQXFT 1321! Risque de non fermeture du moule ! logo area F. Lackner, 1 st Work Group Meeting on Methods and Procedures

Open questions and further improvements: Reproducibility: § Allowing a repetitive positioning of the sliding

Open questions and further improvements: Reproducibility: § Allowing a repetitive positioning of the sliding tool (hole position), add picture to the procedure; § Requires adding QC step; § Use same screw dimensions and distance (end spacer support); § Requires adding QC step. Fatigue: § Replacement of screws obligatory; § Indication in QA procedure required; § Vertical support should be exchanged after n RHT cycles; § Indication in QA procedure required. logo area F. Lackner, 1 st Work Group Meeting on Methods and Procedures

Open questions and further improvements: Friction and axial load: § Sliding needs to be

Open questions and further improvements: Friction and axial load: § Sliding needs to be guaranteed throughout the RHT process to minimize risks of clamping/diffusion bonding: Surface treatment, e. g. coating, mica ? § Which forces are acting on the support due to fixture closure at RT, and during RHT; § Can forces on the tooling be assumed uniaxial; Design: § Implement e. g. belleville washer, spring, flexural guide with optimized cross section/stiffness; § Machine the bar to gain additional clearance; § Chamfer to provoke rupture in case of overstress. logo area F. Lackner, 1 st Work Group Meeting on Methods and Procedures

Could one alternatively leave out the clamps ? § MQXFS & MQXFA are relying

Could one alternatively leave out the clamps ? § MQXFS & MQXFA are relying on the clamping § In a recent exchange with Au. P underlined that the clamping provides an important support to the coil end during the RHT; § § § In 11 T the end-spacer is not axially supported during RHT; Interchanged after RHT with G 11 spacer; No experience with mentioned concern of coil head deformations during RHT. In case of MQXFB the interchange was never tested; Could nevertheless allow to correct/exchange S 2 layer after RHT between cable and end-spacer. Furthermore also the RHT end-spacer could be replaced with the new component. logo area F. Lackner, 1 st Work Group Meeting on Methods and Procedures 8

Proposals: Continue with current procedure: § Add identified QC steps; § Proceed with the

Proposals: Continue with current procedure: § Add identified QC steps; § Proceed with the RHT preparation once all pre-constraints are fulfilled; § Launch RHT of CR 205 (In case no show stopper regarding RHT of 11 T GE 17). Removal of guiding: § Perform RHT of CR 205 without presence of clamping system; § Would allow to observe mentioned deformations due to non-supported coil head; § Lack of statistics in case of no specific findings. In parallel: § Study potential improvements of the design (avoid deterioration of current performance !); CR 03: Test coil § Proposed modifications in the design shall be tested on the CR 03 coil prior considering the design implementation in the RHT procedure for CR 110. logo area F. Lackner, 1 st Work Group Meeting on Methods and Procedures 9

Conclusions § QC was not applied during prototyping phase § Improve towards reproducibility, component

Conclusions § QC was not applied during prototyping phase § Improve towards reproducibility, component fatigue, friction aspects § Adding QC steps § Exchange of critical components exposed to fatigue § Further study parameters and propose design optimization: § In order to allow reducing the friction, adding “buffer” to avoid compressive stress in the coil ends in case of mechanical constraints during RHT § Reduce friction between bar and mandrel block by e. g. surface sputtering § In case the identified further measures are implemented the proposal would be not to diverge from the existing procedure. logo area F. Lackner, 1 st Work Group Meeting on Methods and Procedures 10