Minutes of the Tracker Meeting
- Arthur: write and send out a summary of the baseplate deformation issue.
- Arthur: contact QA people at Nyloc.
- Jeff: get the remaining studs dycronited asap.
- Jeff: procure a better socket wrench for stud installation.† It needs to be longer with a tighter fit.
Peter: get more extraction tools to
- Dave: set up a meeting on the baseplate deformation issue.
- Sandro: update the 1584 procedure with references to the new procedures.
- Dave: set up a call-in for a G&A MRB at Wednesday.
Luca: hand carry MCMs to
††††† - Dave: get a high-level meeting going to push Parlex to perform.
††††† - Jeff: get 10 spare square nuts for test work at Nytemp.
††††† - Jeff: expedite an order for new cable clips for the cable holding fixture.
††††† - Status of tests on tray test articles.
††††† - Status of GSFC etching process.
††††† - Status of preparations for resuming flight production.
††††† - Status of alignment work.† Discussion of issue with re-inserting studs.
††††† - Tower-interface nut/bolt design
††††† - MCM inspection and delivery for Tower A.
††††† - Status of other parts for Tower A:
††††††††††† - cables
††††††††††† - corner brackets
††††††††††† - shipping container
††††† - Tungsten reorder?
††††† - A.O.B.
Action Items from Last Week:
- Ben: weigh the tungsten foils before and after etch.
- Sandro: measure tile electrical isolation with a Keithley.
- Sandro: send a dimensioned sketch of his O-ring idea.
- Arthur: send photos of the cable clip fit problems.
- Martin: extract the clearance of the cable clip screw from the model.
- Sandro: send drawings next week of the ideas for resolving the connector clearance problem.
- Travelers to SLAC: bring shipping cases back.
- SLAC: ship cables with connector savers attached.
Ben sent the following information on the GSFC etching:
††††† We have completed testing of the T-peel and practice
††††† We are now thinking that the tungsten is flexing during the T-peel and causing the BR-127 to separate.† Note that BR-127 is more rigid than the 2216.† The fact that it is very thin makes it act even more rigidly.† This line of thinking would explain why the lap shear tests on pieces from the 700-micron showed the BR-127 with adhesion sufficient to result in 2216 cohesive failure (failure within the 2216), since the thick tungsten adherends did not flex during the lap shear tests.† I am counting on seeing good results this afternoon when we test the thick and thin tungsten using a flatwise tension configuration, which again does not flex the tungsten.
††††† As an aside, the Plyform peel test (
(Note added following the meeting: the flatwise tension test was highly successful.)
Sandro gave the status of
the tray test articles in
Arthur reported that the
alignment work has gone very well.†
However, there is an issue with the locking mechanism: the first test
worked very well, with good running torque.†
But none of subsequent studs have behaved similarly, and they have had very
high running torques. They were able to get 5 or 6 to work by running them
in/out a few sides.† The problem is on
the Grid side as well as the nut side, even though with the EM test there was
no problem on the Grid side.† We need to
talk to Nyloc about the tests they did and demand
more testing.† Also, Arthur proposed to
do thorough tests at SLAC on 100% of the parts and match them with the grid
simulator square nuts.† Also, Arthur said
that 1 square nut had some thread damage but was okay after running a stud in
and out.† 36 studs are presently in
Arthur asked Jeff to get the remaining studs dycronited.†
He also said that we need custom tooling for a longer, better fitting socket for driving the studs.
Arthur said that one inner cone came out of the outer cone when the stud was removed.† They dithered it back in place and kept the alignment intact, so that actually was a good sign.
Arthur still needs to take photos of the clip issues.
There is an issue with the
alignment work.† Repeatability of
measurements of the Grid simulator are not good to better
130 microns, due to changes with how it is held or clamped.† Arthur also said that if you remove a stud
and immediately replace it, it is fine.†
But if you take a stud out and put some weight on the Grid simulator,
then the position is lost and the stud won't go back in.† In general there is a feeling in
Sandro is preparing summary of the test article work.† The flight production baseline will be etched, primed tiles and curing at 35C.† No grounding of tiles will be done.† We will rely on the fact that the resistivity of the glue is such that the time constant for discharge is the order of a second, in which case there is no way the tiles could be charged up by cosmic-ray flux.
The Plyform tent will be
installed by Monday.† INFN will pick up
etched tiles on Monday from the
The MRR is scheduled for tomorrow.
We decided to have an MRB for the G&A production issues Wednesday.† The topics are how to validate trays with no-encapsulation from MCM to SSD and the G&A solution to keep connectors below the surface.† SLAC needs to modify the tray assembly drawings to remove encapsulation and to correct the tolerances for MCM installation.† Sandro sent out a Word file describing the proposed solution.
SLAC needs redlines for the assembly drawing tolerances from Sandro.
Inspection of conformal
coating of MCMs is starting today.† The
pitch adapter traces have been inspected.†
Marcus will execute electrical tests to weed out MCMs with poor margin
with respect to clock duty cycle.† Jeff
will support the shipping.† The goal is
SLAC will send 3 nonflight MCMs to support the cable testing.
Sandro wants 6 MCMs at least to work with at G&A in fixing the MCM bonding procedure.† SLAC will send 6 functional preproduction units (Version 6 GTRC) for this purpose.† There is no stock of nonfunctional MCMs (we generally donít accept them from Teledyne).
Arthur suggested making another
cable bending tool in the
Corner brackets: new ones will be alodyned.† They are now going into the plating shop.† We should have them at SLAC next week.† There is still a need to resolve the clip fit issues.† Arthur said that the top bend will be done Monday on Tower-0, so will know more then.† So far we only have info from the mockup.
Dave reported on the flex-circuit cable procurement.† His blood is boiling, and he needs a meeting between Lowell and the CEO of Parlex; he is planning to threaten to cancel payment to Parlex of the expediting fee in the procurement contract (about $160,000).
Jeff will check the ETA of the outer shipping container.† It is in fabrication.
Arthur wants Jeff to get 10 spare square nuts to send to Nytemp.
Dave wants to send another
cable holding plate and clips to