WP4 cooling update RAL 6 th Oct 2011 -

1. WP4 cooling update RAL 6th Oct 2011 - Welding – high repeatability statistics Bending – 2.275mm OD trials in Titanium with comparison of 1.8” OD bend tests Database – how it is starting to shape up Plans for AUW

2. Plans for AUW • Welding next to electronics • 2nd weld system purchased and delivered to RAL (still in boot of car but on site) • JM to run tests on FEI4 130nm structure – still waiting for readout. • May use simpler test on FEI4 but struggling to get test structures. • Still looks possible to get data and written up for presentation at AUW • Need representative test structure as still outstanding • Welding of tube • Stainless stats – present at AUW • Ti stats should be done in 1/8” OD for AUW (same as SS but some of the testing results may not be returned in ti me) • Will aim to get images on slides of 2mm bore Ti welds – used flared end to bring extra material to joint but get bulbous weld bead • I also will need to take a holiday this year so need to factor this in after AUW looks like most of Dec/early Jan.

3. Welding repeatability statistics 14/9 • Alterations to process and conclusions: • Lab rats: Using 2x mech workshop techs I gave one demonstration of welding & zero instruction other than follow my flow/process chart and press go. It took both 8 – 10 welds to get the hang of the alignment until we repositioned the fixture block collets. I then used tech 2 to press go with zero instruction , followed chart & perfect welds every time. • Why the early failures? = Old electrode used for unknown number of welds. • Why does the machine bring up the weld fail warning consecutively – the machine senses the wear on the electrode and fails to start- this can be repeated twice only before holes appear in the tube • The tubes were even lenghtsto enable the setting of the gas pressure once only – this was not the case, the gas pressure varied throughout the day. The flow meter was poor and replaced, the internal flow/pressure gauge is not so accurate. Borrowing a automatic pressure valve led to exact setting of the gas pressure at the joint – will now implement as may aid purge gas measurement in large volume systems.

4. Weld stats 26/9 to 03/10/11 • Electrode life understood – gas purge and pressure fixed , operators familiar with kit, • 360 perfect welds in a row, zero failures. Took 2 sessions to iron glitches out before highly repeatable process. • Repeat welds every time and now at 489welds without failure on 5th Oct 2011. Going for 500.

5. Early weld statistics conclusions • Early results so still a few to go. • Once glitches in system worked out, 2 people with minimal training have now produced 360 consecutive welds in 316L stainless steel without a single failure. Will stop at 500 consecutive welds as only enough material for 511. • It took 119 welds to fully refine the process to very high repeatability, roughly 2 sessions looking at the problems. • Electrode life is now safely set at 30 uses. Each electrode is £6.05 so £0.20 per weld. • Gas purge system • Accurate pressure measurement needs to be permanently implemented - borrowed automatic pressure valve and sensor – delivers constant pressure to sensor at joint. Only problem is that have to disconnect tee piece for weld. Might try and work out pressure at end of x mm gives x pressure at joint. Not so easy as need to normalise with temperature. • OUTSTANDING WORK ON 316L Tube • NDT results not returned yet. DT results not returned. Still struggling for a reliable tensile test due to problematic mounting of the tube on the strain jigs – universal • Writing up – publication. • Titanium • Will repeat for 3.175mm OD titanium. Have enough material for 700 welds.

6. Titanium Bend Tests RAL. 6th October, 2011 Ian Mercer & Richard French

9. 1/8” Titanium Tube The Tube bent quite nicely with little spring back as you can see in the graph the min out of roundness gets better at 8mm radius the max out of roundness will not change much because it is captured in the radius of the tooling. On visual inspection the tube has creases and signs of flattening on the outside of the radius for the 5,6,and 7mm radius, and then at 8mm and above the bend looks fine. Summary Good tube to bend has little spring back which makes it easier to bend to dimensions, the smallest bend radius that we can bend without defects is 8mm. 2.275mm Titanium Tube This tube is fairly difficult to bend due to the spring back, this makes it harder to bend to the radius and dimensions, in the graph the min out of roundness gets better at 9mm radius as with the other tube the max out of roundness will not change much as it is captured in the tooling radius. On visual inspection the tube has creases and flattening on the 5,6, and 7mm radius, on 8mm and above there are no visual defects. Summary Difficult tube to bend with the large spring back, bending to the dimensions is a lot harder, but can be done with experience on how much to compensate for with the spring back, smallest radius we can bend without defects is 9mm.

10. Atlas Upgrade Construction DB 3 sites: Development Test Production Progressing with the “admin” interface Test users have access to system Alex Owen, Alex Martin, Martin Gibson http://aucdbtest.ph.qmul.ac.uk/admin/