TF 8 - Mesh tension / specifications - Summary on mesh stretching options - Fabian Kuger 1, Esther Ferrer-Ribas 2, Mauro Iodice 3 1 Julius-Maximilians-Universitä.

TF 8 - Mesh tension / specifications

- Summary on mesh stretching options -

Fabian Kuger1, Esther Ferrer-Ribas2, Mauro Iodice3

1Julius-Maximilians-Universitä̈" t Würzburg (Germany) / CERN, 2 IRFU/SEDI - Saclay (France), 3 Roma Tre (Italy)

April 14th 2014MM Mechanics Meeting - CERN

Mesh stretching in labs or industries?(Options)

Main factors to be considered:

2Mesh TF - reportApril 14, 2014

Logistics Cost Quality

Stretching externally in industries

Stretching externally in industries

Stretching ourselves on production site

Stretching ourselves on production site

One centralized supplier

One centralized supplier

Individual supplier per production siteIndividual supplier per production site

One or two ‘stretching sites’

One or two ‘stretching sites’

Stretching in each production site

Stretching in each production site

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

A logistics model for each option will be briefly discussed

Overview – logistics structure

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Logistics

Stretching externally in industries

Stretching externally in industriesOne centralized

supplierOne centralized

supplierIndividual supplier per production siteIndividual supplier per production site

Stretching ourselves on production site

Stretching ourselves on production siteOne or two

‘stretching sites’One or two

‘stretching sites’Stretching in each

production siteStretching in each

production site

Centralized stretching site

‘Drift panel’ siteAssembly site

‘Drift panel’ site+ in-lab stretching

Assembly site

centralized supplier

‘Drift panel’ site

mesh delivery (2)

frame return (1)local supplier‘Drift panel’ site

‘regular’ delivery and pick-up by company

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)

Adds ONE extra logistic step for each (batch of) panel(s). NO extra logistics at all!

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Overview – main cost itemsCosts

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

Size(Module)

2.30 x 2.50 m2

(LM1)1.60 x 2.50 m2

(LM2)1.50 x 2.50 m2

(SM1)1.60 x 2.00 m2

(SM2)

frame (CHF/piece) 220 (176€) 193 (154€) 188 (150€) 1.23 (98€)

Stretching Service: Only stretching - no mesh cleaning or frame preparation included! Huge variance dependent on company.

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Example – centralized industrial stretching

Module LM1France

LM2Italy

SM1Greece Russia

SM2Gemany

Frames (kCHF / 64)1. 14.0 12.4 12.0 8.0

Stretching (kCHF/128)2. 6.8 6.8 6.8 6.8

Logistics (kCHF)3. 5 6 10 6

TOTAL 25.8 25.2 28.8 20.8

Mesh fabric not included!

Option 1: Industrial stretching by one supplierHigh 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)

Costs

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!

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

6Mesh TF - reportApril 14, 2014

Quality

Stretching externally in industries

Stretching externally in industries

Stretching ourselves on production site

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 setup2 pneumatic setup

company dependent

?

Mesh stretching in labs or industries?(Discussion input)

7Mesh TF - reportApril 14, 2014

Costs Logistics QualityStretching externally

in industriesStretching externally

in industries

Stretching ourselves on production site

Stretching ourselves on production site

Choose & quality one supplier

Choose & quality one supplier

Individual supplier per production siteIndividual supplier per production site

Identify one or two ‘stretching sites’

Identify one or two ‘stretching sites’

Stretching in each production site

Stretching in each production site

+

more suppliers to be qualified

Quality assurance seems feasible.

Doing it our self enables us to include

relaxing time improve quality

20-30 kCHF / construction site

23 – 34 kCHF/ stretching site

+ extra logistics

≤ 23 – 34 kCHF / construction site

e.g. 2 deliveries + 1 frame return

transport solutions by the local companies

No logistic issues

Adds one extra transport step

< 20-30 kCHF/ c.s. (lower frames number,

less transport)

Backup

8Mesh TF - reportApril 14, 2014

Backup - Industrial stretched meshes

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Quality

MSW meshes - CERN Prototype meshes - LMU

- 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

Thanks to Elias & Ralf!

Backup - Self stretching - Visit @ GRÜNIG

10Mesh TF - reportApril 14, 2014

Backup - Self stretching - Visit @ GRÜNIG

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Backup - Self stretching @ GRÜNIG - results

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- ± 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

Quality

Notice: Measurements done on the machine, not after gluing!

Self stretching - summary

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!

13Mesh TF - reportMarch 3, 2014

Quality

Backup ‘read-to-use’ setups by Grünig

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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)

Backup – Tension results MSW – Seritec stretching

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Backup – Tension results MSW – Seritec – time stability

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17

REUSE OF TRANSFER FRAME WITHOUT GLUE Mesh Transfer: Standard technique•Transfer frames rise from below•Fast-Glue is applied from the top•Reuse of frame: -Easy twice -More times: Cleaning glue on frame surface

Mesh Transfer: Standard technique•Transfer frames rise from below•Fast-Glue is applied from the top•Reuse of frame: -Easy twice -More times: Cleaning glue on frame surface

Double-screwed transfer frame: •Two coupled frames with

surfaces with grooves and

rubber to act as clamps

•One frame is placed below the

stretched mesh

•The companion frame is

positioned from the top with

correponding holes for

screwing

•Screwing in subsequent steps

making one hole per step in

the mesh

•When all screwed, cut the

mesh and transportCan be reused many times

Can be built in parts

-> easy to transport

Double-screwed transfer frame: •Two coupled frames with

surfaces with grooves and

rubber to act as clamps

•One frame is placed below the

stretched mesh

•The companion frame is

positioned from the top with

correponding holes for

screwing

•Screwing in subsequent steps

making one hole per step in

the mesh

•When all screwed, cut the

mesh and transportCan be reused many times

Can be built in parts

-> easy to transport

stretched mesh

Top frame

Bottom frame

Screw

Tests in progress in RomaTre