Minutes of the Tracker Technical Meeting
March 21, 2001
Tom reported that there are conflicts on the week of the 16th for Tom and Robert to go to Italy. Tom, Robert, Ossie, possibly Bill Althouse, plus Erik and Steve plan to go. The week of April 23rd looks OK, although the 25th is an Italian holiday. The decision was to arrive the morning of April 24th in Milan and visit Plyform the same day. We will drive the next day to Pisa.
Sandro reported on work in progress at Plyform. They have some problems with the 3M glue for edge gluing. It cures adequately at room temperature only after several days. Sandro sent out drawings of the clips for his corner-clip concept. He will continue to study this option. Gwelen asked him to check for interference with the handling fixture for trays (handles, MCM covers, etc).
Tom asked if Hytec can make dxf files of their drawings, for transfer to Pisa. Erik said yes, but he is worried about the impact on drawing control. Gwelen commented that he thought Pisa should have the complete 3-D tracker model to use for designing their assembly fixtures. Robert would like for Hytec to provide the dxf files to facilitate the work in Pisa but insisted that any changes should be fed back to Hytec, and the final drawings for any production (prototype, engineering model, or flight) should be derived from the controlled Hytec drawing set.
Robert, Tom, and Hytec are not happy with the machinability and strength of the SGL CC material, while Sandro and Ronaldo are not comfortable that Alcomp will deliver their material on schedule at a cost we can afford. Robert said that a major action item from the previous week’s meeting at SLAC was for Erik and Tom to begin serious discussions with Alcomp on price and schedule.
Tom asked Erik to ship samples of the Alcomp CC material to Pisa for their own evaluation of the machinability. He could ship some samples to Italy this week, along with the face-sheets that just arrived.
Erik talked to Alcomp yesterday about delivery of the CC material for production. They claim to be very comfortable with a 4 month schedule for the E/M, which is consistent with their past performance. For the flight hardware they would want a staggered delivery with one shipment per month. That means 100 pieces/month arriving after an initial 4-months lead-time, or 7 months total. Tom wants to start the order in November of this year to have all material ready for machining by June ’02.
There was a long discussion on tolerances. All agreed that the removable corner-clip concept looks attractive and could reduce tolerance requirements on the closeout machining. Hytec will try it out on the first 5-tray prototype stackup, in addition to the corner-pin concept.
Pisa requested faster feedback from Hytec on drawings. Tom is getting the web-based virtual meeting going to help out with that. He is also interested in an instant messaging system, but there is a problem of time difference between California and Italy.
Erik reported that he received the face-sheet material this week. They also received the graphite assembly tooling and ten closeout test pieces (without all machining details).
Gwelen reported that UCSC received the MCM layout for review. Several problems are apparent. In addition to some small detailed problems, the layer order was incorrect, and there are issues with some analog traces wrapping around the digital bus. Robert will visit SLAC tomorrow and will meet with the designers. Sergei and Gwelen finished the design for the pitch adapter. The 1st quote was very expensive, so they are looking at other vendors. Gwelen will send the gerber file to Sandro to fab some prototypes at CERN.
Action Items: