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3. Production and control of Bakelite 3.1 Definition and standards

3. Production and control of Bakelite 3.1 Definition and standards. Standard bakelite electrodes are composed by a bulk made of phenolic resin a surface made of melaminic/phenolic resin In the following: Melaminic = bulk phenolic and surface melaminic

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3. Production and control of Bakelite 3.1 Definition and standards

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  1. 3. Production and control of Bakelite3.1 Definition and standards • Standard bakelite electrodes are composed by • a bulk made of phenolic resin • a surface made of melaminic/phenolic resin • In the following: • Melaminic = bulkphenolic and surfacemelaminic • Phenolic = bulk and surfacephenolic SURFACE BULK

  2. 3. Production and control of Bakelite3.2 Quality control data flow Decide limits for accepting a given bakelite sheet on the basis of measurements Bulk resistivityr Determines the time constant of an elementary RPC cell, t = e0(er+ 2 ) r Average roughnessRa It is related to the quality of the surface. A small Ra reduces spontaneous discharges which might affect the RPC rate capability Dielectric constanter It is related to t and to the average fast charge qe of a single avalanche Production Data acquisition Measurement Protocol Out of range Storage

  3. 3. Production and control of Bakelite3.3 Production requirements • Resistivity range : • 2/3 of production in the range r20= 2-5 1010W cm • 100% of production in the range r20= 1-6 1010W cm • Size (thickness = 2 mm): • 1.3 m x 2.8 m “small” slabs • 1.3 m x 3.2 m “large” slabs • Needs: • 3000 (+150) “small” slabs (11466 m2) • 500 (+ 25) “large” slabs (2184 m2) • Total 3675 Slabs (13650 m2) • Average Roughness range : • Ra =< 0.2 mm

  4. Relate the factory parameters to the bulk resistivity How much the resin spreads out on the paper foil Percentage of resin in the paper • Type of Paper • Flow • Resin • Volatile • Heating Temperature • Pressing Temperature • Resin Reactivity Percentage of additives 3. Production and control of Bakelite3.4 Resistivity control Factory Main Parameters: Up Resin GOES r Up Up Volatile GOES r Down

  5. 3. Production and control of Bakelite3.5.1 Temperature dependence The resistivity depends on the temperature T r20/r = exp( a (20-T) ) A measured r value has to be multiplied for a multiplicative factor (r20/r) to obtain r20 ( i.e. r at T=20 C ) r20/r To define a common production protocol we usually quote a resistivity value at T = 20 0C using as normalisation the following experimental curve. T (0C)

  6. Here temp starts to decrease while Then also r starts to increase 3. Production and control of Bakelite3.5.2 Resistivity and Temperature Note also the ``inertia” of the bakelite in following the temperature change T (C) r is still constant r (x 1011) W cm

  7. r20 (x 1010) W cm Slabs 3. Production and control of Bakelite3.6 Resisitivity range Bulk resistivity measurements - melaminic: production is able to reproduce the useful resistivity range

  8. 3. Production and control of Bakelite3.7.1 Roughness range X 600 magnification Roughness Quality Pixel Greyscale Value X (Pixels) Y (Pixels) Qualitative view of the surfaceimproved bakelite. Pixel matrix greyscale of a micro-picture of the surface

  9. 3. Production and control of Bakelite3.7.2 Roughness range Ra (mm) Ra Vertical deviation of the surface from its average profile Measurements points on the surface

  10. 3. Production and control of Bakelite3.8.1 Resistivity measurement Needs good electrical contact between electrodes and bakelite • Brass Electrodes • Upper 5 cm • Lower 10 cm for • guard ring option • We tried several options • for the contact - among others: • sponge with water • antistatic foam (with and without • water) • conductive gel • conductive rubber

  11. V0 V 3. Production and control of Bakelite3.8.2 Resistivity measurement How to measure r ~ 1010 - 1011Wcm r = kV0/(V/R) k = geometrical factor R V0= 500 Volts R= 10 W,100 kW, 1MW Constant pressure (3 atm) on the electrodes

  12. 3. Production and control of Bakelite3.8.3 Resistivity measurement Upper electrode Lower electrode

  13. 3. Production and control of Bakelite3.9.1 Systematic A piston with conductive rubber is continuously measuring the resistivity of a bakelite sample; after a predetermined set of measurements the piston moves up for a fixed time and back down on the sample for the next cycle of measures. Number of cycles, number of measurements within a cycle, time between cycles and time between measurements are supplied by the user. Automatic reading of Temperature and Humidity is provided.

  14. 3. Production and control of Bakelite3.9.2 Systematic 400 cycles of measurements, 10 meas./cycle, 10 sec after each measurements (~13 hours). The resistivity (at T= 20 °C) of a melaminic sample as a function of time is plotted (left hand scale- purple). The recorded value of the Humidity is also shown (right hand scale - blue) 13 hours

  15. 3. Production and control of Bakelite3.9.3 Systematic Frequency distribution of r20/<r20> s = 5,2 % We can measure rat a level of5 %

  16. BAKELITE 3. Production and control of Bakelite3.10.1 Station for resistivity measurement Fixed frame Transverse beams supporting the upper electrodes system Pistons Lifting belt- conveyors bed

  17. 3. Production and control of Bakelite3.10.2 Station for resistivity measurement Upper position of the belt conveyors bed for bakelite loading and unloading Pistons integral to the upper beam of the fixed frame Lateral guide Conveyors belts Fixed frame Mobile frame integral to the belt conveyors bed B Position of the lower electrodes integral to the lower beam of the fixed frame Rectified cylinder B Lower position of the belt conveyors bed for measurements Pneumatic piston for belt conveyors lifting Adjustable feet

  18. 3. Production and control of Bakelite3.10.3 Station for resistivity measurement Side view lengths in mm 1135.0 1135.0 567.5 567.5 1384.8 1316.0 1042.0 position A position B

  19. 3. Production and control of Bakelite3.10.4 Station for resistivity measurement Front view (lengths in mm) 2050.0 520.0 505.0 505.0 520.0 position A position B Bakelite

  20. 3. Production and control of Bakelite3.10.5 Station for resistivity measurement Top view (lengths in mm) 2050.0 1840.0

  21. 3. Production and control of Bakelite3.10.6 Station for resistivity measurement Setup for DAQ and measurements bench-tests

  22. 3. Production and control of Bakelite3.10.7 Station for resistivity measurement 8 Ch, SPST Relays Module 8 Ch, 12 Bit Analog Input Modules RS-232 Network Module 8 ch Universal Discrete Input Module Electronics: modular distributed I/O architecture FIELDPOINT (Nat. Instr.) with analog and discrete I/O modules, terminal bases and network communication module (RS232) DAQ: Labview 5.0x

  23. 3. Production and control of Bakelite3.10.8 Station for resistivity measurement Pre-production Resistivity measurements at the factory Manual Measurements

  24. 3. Production and control of Bakelite3.10.9 Station for resistivity measurement Manual Prototype Pre-production Resistivity measurements at the factory

  25. Slabs at rest for a week • Slab in position • Pistons down • Measurements • Pistons up • Slab is moving out 6 hours / (4 min/slab) ~ 90 slabs/day ~ 1800 slabs/month 3. Production and control of Bakelite3.11.1 Quality control time schedule production Manual Automatic Manual loading measurements unloading stacking 15 sec 4 min 15 sec

  26. Bakelite Production Measurement 3. Production and control of Bakelite3.11.2 Quality control time schedule 1999 2000 Jul Aug Sept Oct Nov Dec TASK Jan Feb Mar Apr May Jun Table delivery Setup Ready to measure at firm 1/10 4/10 5/10

  27. 10 y LHC 3. Production and control of Bakelite3.12.1 Ageing Gamma (137Cs) Irradiation Facility A (A)r vs Temp. (0 C) (B)r20 vs Integrated Dose (Gy) B Source ON Source OFF Melaminic sample

  28. 10 y LHC 3. Production and control of Bakelite3.12.2 Ageing Gamma (137Cs) Irradiation Facility A (A) r vs Temp. (0 C) (B)r20 vs Integrated Dose (Gy) B Source ON Source OFF Phenolic sample

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