Minutes of the Tracker
Meeting
February 12, 2004
Action Items:
Agenda:
1. Grounding tube and tray assembly drawings
2. Bias circuit issues
3. Status of sidewall prepreg specs
4. Progress report on bottom tray and I/F drawings
5. MCM PRR results and status of actions needed to get
materials to Teledyne for flight MCM fab.
6. Status of specs for tray bakeout
7. A.O.B.
Ben reported on some tables
of specifications agreed to with COI and YLA, for prepreg material, including
some cost estimate. Ben had talked to
COI this morning and also confirmed that COI WILL guarantee the mechanical
properties quoted. Plyform now needs to
put the info into their purchasing document.
COI said that they would stand by these values for a buy from Italy. Ben will send the COI info alone to Nanda
and Sandro. He emphasized that there is
no ITAR problem to be concerned about.
Test data generated by COI would be available to Plyform (but they would
not tell Plyform exactly how they do the tests). We will get a clear status from Nanda next Thursday, including a
date when the prepreg will be ordered.
Sandro wants to be sent the
requirements for testing the laminate.
Ben will write down a test matrix, which will be essentially what was
done in the past, minus the conductivity and insert tests. Ben said that he had asked Plyform to redo
their calculation of the modulus for their tensile test. Also he wants them to describe the failure
modes of their test coupons using ASTM nomenclature. He is waiting for that information.
Ben said that he is
satisfied with the Plyform face sheet prepreg spec and the ESPI method for
evaluation of the sandwich.
Sandro reported that he and
Jerry agreed on using Sandro’s method for the grounding tube assembly. Assembly drawings will be rev’ed to correct
the grounding tube drawings. Jeff Tice will
pass that by Mike Foss and will run down the action to revise the drawings and
submit them again for sign-off.
Mike reported on several
items:
1.
In
Pisa they spent time discussing the tower assembly fixture and concerns about
the countersink screws negating the alignment initially achieved with
pins. They concluded in belief that
with the 120 screws the centering force is small and the tower will hold the
initial alignment.
2.
They
discussed in detail the Ti parts drawings.
Martin has been making small dimensional and tolerance changes. They also fixed the specifications and
tolerances on the alignment holes used to position the inserts in
closeouts. They also added a tapped
hole in the corner brackets to hold a grounding wire, since the grounding tubes
won’t work on the bottom tray (the M55J doesn’t conduct well enough).
3.
They
discussed assembly of flexures to brackets and indexing of the cone. They believe that if they can hold the
tolerances specified on the Ti parts, then at 3 points the tower can be mounted
on single concentric cones. This is the
preferred integration strategy, to be replaced by all dual cones only if a Grid
bay or bottom tray comes in out of tolerance.
4.
Mike
emphasized the need to send an engineer to the machine shop to go over the
drawings and also to be present when they CMM the first articles.
5.
Mike
proposed for a repeat vibe test to put dual cones at all 12 places, to qualify
that worst-case configuration.
6.
Shipping
containers: INFN will provide SLAC a sketch of what they want. The same also for the lifting fixture.
7.
Thermal
strap: INFN will redline the thermal strap drawings to reduce the risk of the
mounting screw threads producing copper shavings. We also need to verify with Jack Goodman the need for RTV on them
on the Tracker side in assembly.
Mike Foss need to mail pdf
files of the completed prints for Martin to check on the way home.
The plan is to release
drawings on Tuesday. It is urgent to
get a PO in place, which requires a requote to the new drawings (the biggest
change is the new requirement to assemble the flexures to corner brackets and
drill the conical holes.
Martin expressed concern
about the tight profile tolerances on the flexure blades and whether the shop
could accept the drawings. In fact,
those drawings were quoted to by Advanced Machining. Also, the same tolerances were in the drawings used by
Continental Machining to make the EM flexures.
(Later Erik reported that Continental Machining claimed to be within
tolerance on the flexure profile requirements, according to their inspection
reports, but the LAT did not do an independent verification.)
Mike and Martin discussed
with Sandro the impact on Tower A if we do repeat vibe test with the new
interface configuration. Robert
emphasized that schedule exigencies may dictate using the second bottom tray
for the vibration test (with the first going to Tower A). There was discussion of the Ti
schedule. Robert said that Advanced
Machining gave Tom Borden a verbal estimate of 4 weeks to get the first
articles out. The 8 to 10 weeks
estimate is for the entire flight lot.
We need to keep in mind,
when finalizing the PO, the need for one extra set of parts for the EM tower
and parts for joint qualification testing.
Sandro asked for
confirmation that we will not do T/V cycles following the thermal-balance
test. There seems to be agreement among
everybody to strike the cycles from the test plan.
Sandro reported that the
honeycomb will be at INFN tomorrow morning.
Also, Pisa will deliver 7 MCMs to G&A tomorrow.
Sidewalls will go to Terni
tomorrow for thermal testing.
Erik reported that the
static test fixture is still in Los Alamos.
There is snow, so he was skeptical that the truck would make the pickup
(late-breaking news: it did get picked up).
Erik is putting together a
report on how to do the static test.
After that we will re-evaluate the need for Erik to travel to Italy to
transfer knowledge of the test procedure.
Sandro needs to identify
somebody in Italy who owns responsibility for the test. Mike also felt that we need to identify
somebody at SLAC to take ownership of the test and the specifications.
Robert reported that the MCM
PRR was a success on Tuesday at Teledyne.
The onus is on SLAC to get the parts down there to start flight production
next week, in which case Tower-A MCMs could be done and burned in by the end of
March. The long poles are screening of
the pitch adapters, testing of the PWB coupons for already machined boards and/or
machining of boards from panels already tested, and receipt of new connectors
from Omnetics.
We will meeting Friday at
8:00 by phone between SLAC and Pisa for an update.