Minutes of the Tracker Meeting
May 22, 2003
Sandro is in G&A tomorrow to begin gluing ladders on EM mid trays.
The trays have been cleaned.† Vacuum tests at Alenia started with 3 trays.† They will do this with all trays.† They have finished the holographic tests on EM mid trays.
Plyform is machining tray assembly tools to correct them for top/bottom trays.
They are ready to put inserts into top tray closeouts.
Bottom-tray inserts are of 4 types; they are making them in an outside machine shop, and they should be ready by the end of next week.
Closeout walls shipped from COI yesterday to SLAC.† They will leave SLAC tomorrow by DHL to Pisa.† There are 9 pieces (1 extra).
Luca requests that SLAC include an MCM with new chips in the shipment.† Hartmut will take the MCM back to SLAC for shipment to Pisa (note: it turns out that Gunther Haller needs all the spare MCMs to do a readout test with a full string of 9 MCMs).
Top/bottom face sheets are at Plyform
Tom will bring corner brackets with him on the 4th and then be at Plyform on the 6th for assembly.† We need the inserts in and sandwiches done before then.
Tom asked for confirmation whether Plyform will do finish machining on the short panels.
Pisa is close to freezing the drawings for the tower assembly fixture.† They have ordered some parts.† G&A will machine it.
It was suggested that we could take the UCSC-assembled MCMs to Teledyne to encapsulate them.
Tom reported that the Teledyne SOW is being looked at by procurement and is at the directorís office for signature.† Tom making a list of values of all the government furnished equipment.
Jeff reported that he is still working on getting an order out for the Tantalum capacitors.
July 8 is the delivery date for most of the resistors.
Eduardo asked that Robert look at the data from the funny MCM in the mini-tower, which seems to be a mixture of F and G chips.† (MCM 77 is definitely 100% G chips.)
Monday, May 26, 2003, phone meeting with Sandro:
G&A is producing the encapsulation dam, which should be ready the 1st week of June.
Ladders are going on before MCMs for the EM.
5 tools are ready for ladder installation, so Sandro believes that they can catch up with the schedule.† G&A has started 2 trays.† For the MCMs they will use the new tool (in production).† For pins they will not drill out the closeouts but will probably use screws with threads removed.† However, the bottom trays need the full-size pins.† There was a discussion about what to make the pins out of.† The conclusion was to use brass.† The existing screws are A286 stainless steel.† Sandro will send the brass type to Tom to put on the materials list.
Robert described problems and delays with the new MCM production.† The PWB vendor did a sloppy job of putting on the raised strip and machining the radius.† We tried to recover all but 4 of them by machining them down further a little bit.† The other 4 were judged to be good enough.† However, a slight discontinuity in some places between layers along the wire-bonding edge appears to have cracked some traces.† The PWB vendor was supposed to put on the edge oversized and then precision machine the whole thing down, but instead they cut the board to size and then tried to add the strip.† Furthermore, they did not machine the complete 90-degree radius (they didnít bring the bit in close enough).† We remachined the radius on all boards to 1mm before even going to Teledyne.†† For future production we will have them put the strip on oversized, and then we will machine them.† Some of the reworked parts caused problems when trying to trim the pitch adapter, because they did not fit properly into the cutting jig.† Tom will fly to LA tomorrow to review what has been done and make a tally of how many parts are usable for going on with electronics mounting.† Most likely some of the parts will have to be reworked by removing entirely the raised edge and bonding on a new one.† However, only 2 unused pitch adapters remain, so more may have to be produced.† The good news is that the pitch adapter looks good on boards that have a smoothly machined radius.† The clear lesson is that even small discontinuities or bumps in the glue cause cracking in the traces (the nickel plating is brittle), so the machining has to be done very carefully and seems to be beyond the means of PWB houses.† For this production we are looking at a delay of 1 to 2 weeks because of this.