Engineering meeting #3 - Implementation of disizing in magnet frabrication

Wednesday 24 Sept 2025, 09:00 → 10:00 Europe/Zurich

927/1-B23 (CERN)

Attendees: Daphne Vassilena Beaujoint, Pavan Chaganti, Arnaud Pascal Foussat, Mikko Karppinen, Javier Osuna, Ignacio Perez De Lazarraga Viguri, Francois-Olivier Pincot, Nicolas Peray, Roland Piccin, Nicola Sala, Ezio Todesco, Dimitrios Tolis.

During this meeting, we started from the assumption that we want to de-size the glass fiber present in the coil and we covered the 2 main techniques. Proof of principle of both techniques exist and electrical tests validated the non-impact on the strand superconducting behavior. About the implementation:

• Desizing by heat treatment by including an oxygen step during reaction
• test to define best temperature and time with minimum impact on reaction cycle (450C, 1h)
• the type of sizing is important: 633 is designed to be removed, however 933 is less problematic, electrically speaking as insulation remains better
• History point: de-sizing has been applied directly on yarns and the sizing was replaced by phenolic acid, more volatile.
• main problem: only 1cm penetration in a coil representative stack. Hard to imagine a 15m mold where we assure the penetration of oxygen and the expulsion of the residues everywhere 
• secondary issue: oxidation of reaction tooling
• De-sizing by plasma directly on the cable prior to winding
• typical nozzles are covering 5-10 mm, rotating nozzles reach 30 mm
• unknown: braiding is more fragile afterwards, to be tested during a real winding
• when: can be applied right after braiding in the same line or during re-spooling. Not easy to use during winding due to the lack of continuity of this process. 
• What about the impact on the Mica? Unknown
• Conclusions:
• For FG layers, the heat treatment remains the best option in terms of feasibility and efficiency
• For FG braiding around cable, the plasma is the preferred option with a plasma unit to put in line during re-spooling
• Plan:
• Few meters of BOX cable are being de-sized at the company and will give first impression/results in a BOX.
• Action: the double, rotating nozzles machine will be leased for a year to be installed on the re-spooling line in the winding workshop. It will be used to de-sized 1 UL of SMC MQXF.