Minutes of the Tracker Meeting
May 13, 2004
- Dave: discuss with Jack whether a carbon filter is enough in the bakeout vacuum chamber.
- Mike: send correct vibe fixture drawing out for release
- Arthur: send the updated cone installation and alignment plan to Italy
- Jeff: procure Aeroglaze 9929 primer
- Riccardo: send redlines of tray-panel drawings to SLAC for as-built condition, as discussed in Pisa
- Sandro: send redlines of tray-assembly (G&A) drawings to SLAC to conform to the actual procedure
Aluminum: Jeff has 7075-T73 bars arriving from LA tomorrow. ½” bar is kind of large. Martin is looking into other materials. He wants Emilio to check on availability in Italy. He will send Email to Emilio on what materials to look for, including titanium. Ben said that titanium may require an anti-gall coating. Paul Baird noted that GSFC can get titanium rod for cones in 4 days.
Emilio reported that the bakeout procedure will be ready on Saturday. He said that a cold trap is not possible but the pump has a carbon filter to prevent oil from entering the chamber. Dave will discuss with Jack Goodman whether this is an issue for such a vacuum chamber (not high vacuum).
Mike reported on the lifting fixture design. Not all insert locations are available because of the cables. John Ku did some stress analysis and thought it was okay, but Emilio wanted more margin for handling stresses. Mike is now developing an alternate concept.
Mike also reported on the cable holder design. He wants the cable to go halfway and loop back. Some concern was expressed about bending the cables, so Mike will do an experiment. He recommends using connector savers.
Vibe fixture drawings were sent to Natalie yesterday for approval. Mike forgot to remove “check print” from the drawings, so he will fix that.
Mike expressed an urgent need for INFN to write a procedure for installation of a tower or bottom tray onto a fixture, using the cones. Arthur nearly has an update for the assembly plan draft, which he will send soon to Italy.
Arthur is working on tool design. The highest priority tool is the cone extraction tool. The second priority tool is a spanner wrench. Another 2 tools are for setting alignment---less priority.
Chris asked about the status of software for alignment. Dave said that he met this week with Tom Borden. The AI&T tower simulator will be used alignment trailblazing. All necessary features can be put into that simulator. Robert Ruland’s team will use it for development of software and procedures. The test is scheduled for the first week of June.
There was some discussion of using the EM tower for practicing the alignment procedure in Italy.
Cable clips: John is doing the stress analysis now. They are made of aluminum and will be installed onto a completed tower. Custom nests are used for tooling balls. The nests stay there during vibration but are removed before the ACD is mounted. The assembly sequence is to prebend the cable and install. Then put on sidewalls. Then turn the tower right side up and slip the bracket under the cable.
Cable bending tools: Arthur is working on the S bending tool for cactus arms: it will be procured this week. He has a concept for the bending tool used at the Grid interface. Nothing has been done yet on the top tray bend. Arthur will do it.
Pisa needs to check out the EM-2 EGSE using the newly released procedure. Robert will send the documents to Luca. Dave Nelson and Hiro are working on a breakout board to allow currents to be measured.
In a discussion of primers for the black paint it became evident that we need an NCR written. The 9924 primer has been used instead of the 9929 called out on the drawings. Jeff needs to procure the 9929 primer immediately. The 9924 is suitable for aluminum but is not ideal for carbon composites. Test at Pisa indicated a need to use primer on the carbon-carbon. The paint peels without primer. With the 9924 primer it does not peel. Jeff will ask the manufacturer about experience with 9924 on graphite, as opposed to carbon composite.
Flex cables: Martin reported that they are updating the flight drawings now following his redlines. Final check prints may be available as early as tomorrow. He expects to start the release cycle middle of next week. First we need a final check against electrical layouts.
Sidewall prepreg material will ship next week to Plyform. Plyform may have to start their job in parallel with COI testing, due to a long time lag in the testing. Nanda requested that we get Ben involved with COI to get an early indication of success in the testing.
Jeff is ordering nuts for the vibration test. The static test can use standard stainless nuts with a lubricant. There was a discussion about contamination and it was resolved that we just have to clean the flight tray after testing, in case some lubricant gets onto the flexure.
Jeff reported that the static-test Grid simulator will arrive the 17th or 18th, then will be CMM’ed at SLAC. There is no coating on the first one. The second one will have a black anodized surface.