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Flex attachment to the stave Glue selection: preliminary tests. 30/08/2011 Maxence CURDY François-Xavier Nuiry. CERN PH/DT/PO. Flex to stave assembly. Genova flex. Goal : Realise a reliable and accurate fixation between the flex and the omega carbon skin Accuracy / omega:.
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Flex attachment to the staveGlue selection: preliminary tests 30/08/2011 Maxence CURDY François-Xavier Nuiry CERN PH/DT/PO
Flex to stave assembly Genova flex Goal: Realise a reliable and accurate fixation between the flex and the omega carbon skin Accuracy / omega: Better than +/-0.3mm About +/-0.1mm Technology used: Glued joint Stress in the glue: Currently tested (through several shear tests) and also under calculus The total force considered : Flex Glued over ~350mm Max stress Max stress F F 2F=(ES)/L * (thermal contraction)= (11500*0.6*11.5)/350 * 0.55 = 125N F~62.5N, If the flex young modulus is 11.5GPa
Flex to stave assembly Genova& Bonn flex 65 test samples manufactured Cleaning at surface treatment workshop Surface activation with Plasma Shear tests Glue selection
Plasma set upPolymer lab at CERN Displacement in X with the handle
Preliminary information on Kapton surface activation • Speed and Distance between the BLASTER nozzle to substrate surface (Kapton) have to be determined in order to stay under 120⁰C. ( given by Rui) • But tests show that we need to heat a bit to activate the surface. • So we must find a compromise between speed, height and number of run.
Plasma Tests Performed on KaptonCleaning with ACETONE -->ETHANOL
Wettability control on Kapton sample LF 7001 (13μm) The effect of plasma treatment can be controlled by a wetting test. But this is just a visual check, it’s not precise. Not activated surface Activated surface When the nozzle is adjusted at 8 mm and no displacement T⁰C max about 160⁰C
Treatment control The treatment can also be controlled with test ink. When the surface tension is high the surface became wettable and it’s easier to glue it. 42mN/m We control the surface tension to 70mN/m. The control of the surface tension shows that from 4 run, the number of run doesn’t influence activation. Kapton 70mN/m Kapton after 4 run, 8mm and 8cm/s 70mN/m Kapton after 6 run, 8mm and 8cm/s
Procedure for glued samples • Glue preparation • Series of 5 Kapton specimens are activated (4 runs) directly between two foils of 0.6mm (no time lost for gluing). • Put glue on the Kapton (4*4mm) and calibrate glue with foils (10μm of glue). • Position carbon fibre specimens on a levelling pad. • Glue the Kapton on carbon fibre specimens. 2 3 Glue Activation 4 5 Kapton + Carbon Fibre specimen
Glued samples Thermal cycling 100 cycles Temp ˚C +50 -40 Time, min 50 minutes