TF 8 - Mesh tension / specifications - Summary on mesh stretching options -

1. TF 8 - Mesh tension / specifications- Summary on mesh stretching options - Fabian Kuger1, Esther Ferrer-Ribas2, Mauro Iodice3 1Julius-Maximilians-Universitä̈t Würzburg (Germany) / CERN, 2 IRFU/SEDI - Saclay (France), 3 Roma Tre (Italy) April 14th 2014 MM Mechanics Meeting - CERN

2. Mesh stretching in labs or industries?(Options) Main factors to be considered: Stretching externally in industries Stretching ourselves on production site One centralized supplier Individual supplier per production site One or two ‘stretching sites’ Stretching in each production site Logistics Cost Quality A logistics model for each option will be briefly discussed • Depend strongly on logistics • Varies a lot with the supplier • Example calculation will be given, not to be considered as final  Intensively discussed in the weekly meetings. Today only short summary, More detailed results in backup Mesh TF - report

3. Logistics Overview – logistics structure Stretching externally in industries One centralized supplier Individual supplier per production site ‘regular’ delivery and pick-up by company mesh delivery (2) frame return (1) centralized supplier local supplier ‘Drift panel’ site ‘Drift panel’ site Large number of frames, to be reused only one or two times to reduce logistics(-costs).(1000 – 3000 CHF per transport) Smaller number of frames in two batches, one at site and one at supplier, to be exchanged. (few 100 CHF per transport) Stretching ourselves on production site One or two ‘stretching sites’ Stretching in each production site ‘Drift panel’ site+ in-lab stretching ‘Drift panel’ site Centralized stretching site Assembly site Assembly site Adds ONE extra logistic step for each (batch of) panel(s). NO extra logistics at all! Mesh TF - report

4. Costs Overview – main cost items Frames: Each stretching in industries solution requires an amount of (reusable) frames to pre-stretch and transport the meshes. Buying directly from producer saves up ≈ 50% compared to stretching companies. Exact numbers depend on logistics e.g. 2x 16 frames  8 logistic steps; 2x 8 frames  16 logistic steps Stretching Service: Only stretching - no mesh cleaning or frame preparation included! Huge variance dependent on company. Mesh TF - report

5. Costs Example – centralized industrial stretching • Option 1: Industrial stretching by one supplier • High number of frames and less reusing will be cheaper than many transports – e.g.: • Buying half of the frames (64) and reusing them once • 3 transport steps with full truck (2x company  site, 1x site  company) Mesh fabric not included! 1.based on Hurtz offer 2. based on Pröll offer 3. Based on 3 transports, e.g. from CERN to ‘drift panel’ site Option 2: Industrial stretching by local supplier • Lower number of frames sufficient • More logistics steps, but each one much cheaper • BUT: Prices for stretching might differ significantly! Mesh TF - report

6. Quality Summary • Quality highly depends on supplier  Individual qualification and QC necessary with each supplier • Time for relaxing the mesh on the stretching setup before gluing is very expensive in industries  difficult adjustment to nominal value • Best Quality delivered so far ±3N/cm over 110x150cm Stretching externally in industries Stretching ourselves on production site • First tests have been performed with satisfying results: • < ±2N/cm over 100x100cm1 • < ±1N/cm over 80x100cm2 • Improving our handling of the tools should improve this further • But: Neither full size, nor gluing process have been tested! • Workload is reasonably small(< 30 min per mesh) • 1 Mechanical setup2pneumatic setup Mesh TF - report

7. Mesh stretching in labs or industries?(Discussion input) Costs Logistics Quality Stretching externally in industries Choose & quality one supplier company dependent e.g. 2 deliveries + 1 frame return 20-30 kCHF / construction site ? Individual supplier per production site transport solutions by the local companies more suppliers to be qualified < 20-30 kCHF/ c.s. (lower frames number, less transport) Stretching ourselves on production site + 23 – 34 kCHF/ stretching site + extra logistics Identify one or two ‘stretching sites’ Quality assurance seems feasible. Doing it our self enables us to include relaxing time  improve quality Adds one extra transport step Stretching in each production site ≤ 23 – 34 kCHF / construction site No logistic issues Mesh TF - report

8. Backup Mesh TF - report

9. Backup - Industrial stretched meshes Quality MSW meshes - CERN Prototype meshes - LMU Thanks to Elias & Ralf! • 7 – 21 N/cm (min-max), 10 N/cm nominal • Systematic inhomogeneity, huge difference between meshes • time stability (4 Months) proven: • temperature depended deviation observed, • otherwise deviation ≤ accuracy of measurement results in backup slides • 12 – 17 N/cm (min-max), 13 N/cm nominal Mesh TF - report

10. Backup - Self stretching - Visit @ GRÜNIG Mesh TF - report

11. Backup - Self stretching - Visit @ GRÜNIG Mesh TF - report

12. Backup - Self stretching @ GRÜNIG - results Quality • ± 2 N/cm (max) • ‘pre-stretching’ of the mesh is important! • quality is skill dependent • larger size might increase difficulties • ± 1 N/cm (max) • Individual clamp movement improves homogeneity • good repeatability • no concerns about larger size Notice: Measurements done on the machine, not after gluing! Mesh TF - report

13. Self stretching - summary Quality Stretching the meshes our self with professional tooling… … seams quiet easy to learn, … doesn’t create a huge workload, (<15 min to install & stretch the mesh, 2 persons required) … and yields satisfying quality in terms of homogeneity … but does not come cheap! (23-34kCHF) (renting / reselling the tool tbd…) Stretching with self made setups (INFN, Class12) … … is much cheaper … seems to yield satisfying results as well … but requires more work and additional R&D With self stretching, we have the quality of the product in our hands and decrease dependence from industries! Mesh TF - report

14. Backup ‘read-to-use’ setups by Grünig offers ‘read-to-use’ setups capable to stretch up to 2500x2500 mm2 with ≤ 50 N/cm. • Mechanical tensioning setup (G-Stretch 210) • fast and continuously adoptable to smaller frame sizes • pre-tensioning of the frame • no frame-mesh contact during tensioning • clean room capable • costs: 23.000 CHF • Pneumatic tensioning setup (G-Stretch 215) • individual movement of the clamps •  compensation of clamping uncertainties possible • costs: 33.800 CHF • Automatic pneumatic tensioning setup (G-Stretch 215A) • very simple to use (click here for demonstration video) • automatic compensation of clamping uncertainties •  higher homogeneity of the mesh tensioning • costs: 43.000 CHF Show-room setups can be visited and tested. (Schwarzenburg – 170km, <2h by car from CERN) Mesh TF - report

15. Backup – Tension results MSW – Seritec stretching Mesh TF - report

16. Backup – Tension results MSW – Seritec – time stability Mesh TF - report

17. Reuse of Transfer Frame without glue Top frame • Mesh Transfer: Standard technique • Transfer frames rise from below • Fast-Glueisapplied from the top • Reuse of frame: • Easy twice • More times: Cleaningglue on frame surface • Double-screwed transfer frame: • Twocoupledframes with surfaces with grooves and rubberto actasclamps • One frame isplacedbelow the stretchedmesh • The companion frame ispositioned from the top with correpondingholes for screwing • Screwing in subsequentstepsmakingonehole per step in the mesh • Whenallscrewed, cut the mesh and transport • Can be reusedmanytimes • Can be built in parts • -> easy to transport stretched mesh Bottom frame Screw Tests in progress in RomaTre