*Pixel Panel Construction Procedure For PC-3*

![](media/image1.jpeg){width="6.160416666666666in"
height="3.9402777777777778in"}

Documented by: S.V. Greene, & J. Fellenstein

Written by: K. Adcox, & D. Borland

October, 1999

## **Table of Contents**

## **Day One: Frame Construction**

## 

## Preparation of Parts

Tooling/Table Arrangement

Board Alignment

Dry Layout

Taping of Center Seam

## Applying Epoxy to Frame

Securing Frame

**Day Two: Completion of Panel/Vacuum Bagging**

Dry Layout

Preparation of Parts

Mixing and Application of Epoxy

Vacuum Bagging of Panel

Clean-Up

**Day Three: Terminal Board Support Blocks**

Preparation of Parts

Dry Layout

Application of Epoxy

Securing Wire Support Blocks

## **Day 1: Frame Construction**

**Preparation of Parts**

*Pixel Circuit Boards \# 382,383:*

-   Using the notes from the laboratory logbook, verify that all
    plated-through-holes were correctly repaired.

-   Ensure that all plated-through-holes are sealed from the spider side
    by testing each hole with the conductive rubber clip, test pin, and
    buzzer.

-   Measure the distance from the outer edge of the guard ring to the
    outer edge of the board. The distance should be 111.25 mm. If it is
    not, trim accordingly with a file.

-   File down any solder/epoxy protrusions located at the seam beam edge
    on the pixel boards.

-   Clean the entire board with methanol, especially those areas of the
    board that will directly touch the frame.

    *Fiberglass Beams:*

-   Select the necessary parts (9 pieces) and inspect them for any
    obvious damage or imperfections.

-   Using methanol and Kimwipes, clean each piece. Use gloves while
    wiping down the parts since they are made of fiberglass and can
    easily send tiny shards into the skin.

-   All seam beams and panel heads will have been pre-tested for gas
    leaks.

**Tooling/Table Arrangement:**

-   Using a file, remove any dried epoxy from all fixtures and tooling
    plate edges.

-   Apply mold release to a 4" wide strip around the edge, a 12" wide
    strip down the center of the tooling plate (where the seam-beam
    sits), and all fixtures.

-   Place a 4" wide Mylar strip around the edge of the tooling plate, as
    well as down the center of the panel.

-   Corner #1 and side fixture #2 are fixed. All other fixtures are
    initially loose.

-   Placement order of fixtures is shown in the logbook, beginning with
    1 and ending in 10. No toggle clamps will be set until all fixtures
    are secured to table.

-   To verify that the plates are aligned, secure fixture \# 1 to table.
    Then secure fixture \# 2 to table. Use fixture \# 7 to align edges.
    When aligned, the divots on each tooling plate should form a perfect
    circle.

**Board Alignment:**

-   Place boards on tooling plate with panel head at side A.

-   Put panel-head end rail and pocket-beam end rail into position.

-   Place corner fixtures \# 3,4,6 into position.

-   Screws should have more than 3 threads and should not protrude from
    fixtures.

-   Verify that the small holes in the panel-head end rail face down
    toward the table.

-   Place the appropriate shim between both boards . This will set the
    spacing between boards.

-   Center boards in frame by measuring from the fixture to the pixels.

-   Locate board along Z axis by having boards touch the panel-head end
    rail. If necessary, trim by filing.

-   Check alignment of pixels and adjust accordingly.

-   Check all dimensions and adjust if necessary.

-   Apply sandbags.

-   Remove tooling except #1,2.

-   Remove pocket-beam end rail.

**Dry Layout:**

#### Order of parts

-   Panel-head end rail (already in place)

-   Side rail.

-   Panel head and square face plate

-   Seam beam

-   Pocket-beam face plate

-   Pocket beam

-   Side rail

-   Pocket-beam end rail

#### Inspection

-   Add tooling in the order indicated in the logbook.

-   Check that gaps exist between parts to accommodate the glue.

-   Make sure the end rail is flat against the fixtures and not on top
    of the boards.

-   Verify that the panel head is oriented correctly. All counter bores
    should be up and at outer most edges.

-   Remove all beams and tooling except \# 1, 2.

**Taping of Center Seam**:

-   Use a ½" diameter rod to raise one of the center edges on the panel.

-   Lay a 2" wide strip of kapton tape on the table and underneath the
    raised edge.

-   Remove rod slowly and allow edge to drop onto tape.

-   Raise the other edge above the remainder of the tape.

-   Drop edge in place and roll seam to ensure good contact between tape
    and board.

**Applying Epoxy to Frame**

-   Use DP-460 Epoxy.

-   Check that Mylar is in place and not extending over or under the
    edge of the tooling plate.

-   Visually inspect gluing surfaces.

-   *Center Seam* - Put bead of epoxy along seam. Do not roll.

-   *Panel Head End Rail* - Roll a light coat on the inner surface. With
    HOLES DOWN, put into place, making sure it is flat against the
    fixtures.

-   *Side Rail* - Roll epoxy onto bottom surface, ends, and 5" along
    inner edge.

-   *Panel Head* - Roll epoxy onto bottom surface, outer edge, ends,
    ring around gas hole (both sides) and a few inches on the inner edge
    center. Hold in location and drop down into place.

-   *End plate* - Apply epoxy to faces and ring around the hole. Put
    into place. To clean the hole, twist paper towel into rod or use a
    Q-Tip.

-   *Seam Beam* - Roll epoxy onto bottom surface. Apply epoxy very
    generously to ends. Drop into place (on center of seam). Raise beam
    up and add epoxy to dry spots. Drop into place again. Add seam beam
    spacers (square) with Mylar epoxy shield.

-   *End Plate* - Apply epoxy to both faces and put into place at end of
    seam beam.

-   *Pocket beam* - Roll epoxy onto bottom surface, outer edge (pocket
    side), ends and a few inches on inner edge center. Put into place.

-   *Side Rail* - Roll epoxy onto bottom surface, ends, and inner edge
    ends. Put into place.

-   *End Rail* - Roll epoxy onto inner edge and put into place.

    **Securing Frame**

-   Add fixtures in correct order (see "Dry Layout").

-   Add C-clamps (not too tight) and then fixtures. Release clamp,
    retighten clamp, and iterate.

-   Add metal corners and shims (using Mylar underneath) until fixtures
    exert appropriate pressure on the frame.

-   Use a screwdriver to push end rail down (pocket beam side).

-   Set the side toggle until end rail *barely* clears the tooling plate
    (\~ 0.0005"). You should see a slight reflection.

-   Add sandbags along seam beam. Release and reset side toggle.

-   Check the seals around the seam beam ends and the edge of the pixel
    boards.

    **Day Two: Completion of Panel/Vacuum Bagging**

    **Dry Layout (one side at a time)**

-   Put the plastic covers on all the kapton cables, making sure to use
    a loop of tape between the cables and the cover to reduce risk of
    cover slipping off.

-   Lay one large rod and one small rod between each row of cables.

-   Place the honeycomb (cut and blown out) on top of the rods.

-   Remove large rods one by one, guiding cables into holes as honeycomb
    lowers.

-   Remove small rods, letting honeycomb drop into place, being very
    careful not to pull the plastic cable covers loose.

-   Check that the honeycomb is level with frame. If not, cut a bevel on
    the honeycomb edge.

-   Lay large and small rods on top of honeycomb and between cables
    again.

-   Place motherboard on top of the rods.

-   Remove rods one at a time, guiding the cables through the holes. Pay
    careful attention again to the cable covers as the motherboard drops
    into place.

-   Check the fit of the motherboard. It should sit inside the lip. If
    it doesn't fit, then file it until it does.

    **Preparation of Parts**

-   Remove all excess glue from frame, especially from ledge where
    motherboard rests.

-   If the seam has solder bumps underneath, taper the joint between the
    seam beam and panel head and between the seam beam and pocket beam.

-   Clean copper side of motherboard with methanol.

-   Clean spider side of the pixel board with methanol.

-   Place paper protectors around connectors.

    **Mixing and Application of Epoxy**

-   Use 3M Scotchcast Electrical Resin 8; pot life is 1 hour and 15
    minutes.

-   Measure 750 grams of each part into separate containers (A and B).

-   Measure an extra 200 grams of each part and set aside to be used if
    needed.

-   Gently and slowly, roll epoxy onto back of pixel board, being
    careful not to spray epoxy everywhere.

-   Roll epoxy on back of honeycomb (stay \~ 3/4" away from holes).

-   Roll epoxy on inside of beams.

-   Brush epoxy on inner seams between board and frame corners.

-   Use syringe on area behind innermost connectors.

-   Remove paper protectors around connectors.

-   Put honeycomb in place (as in dry layout), being extremely careful
    with the plastic cable covers.

-   Roll epoxy on surface of honeycomb.

-   Roll epoxy on copper side of motherboard, staying away from the
    holes.

-   Put motherboard in place and check fit.

-   Clean excess epoxy with methanol.

-   Repeat for the other side.

    **Vacuum Bagging**

-   Put wood blocks over the holes and cables in the motherboard.

-   Put blue Mylar over seam beam.

-   Add wood blocks to cover the gas fittings so the vacuum bag doesn't
    implode.

-   Add vacuum fitting above seam beam.

-   Cover with 2 sheets blue Mylar, 2 sheets breather cloth, 1 sheet
    plastic vacuum bag (with edges folded in).

-   Put chromate tape around perimeter of table.

-   Remove top paper from tape.

-   Attach plastic to tape everywhere *except* at the corners.

-   Add extra tape to corners and compress.

-   Check all tape for possible leak paths.

-   Place a sandbag in each corner to keep bag taut.

-   Apply vacuum.

-   Work bag over breather cloth.

-   Manually apply pressure to motherboard/side rail

    **Clean-Up and Preparation**

-   Scrub pixels and motherboard with emery paper to clean excess
    oxidation from the copper.

-   Clean all surfaces with methanol.

-   Remove excess epoxy from center of motherboard with a razor blade.

**Day 3: Terminal Board Support Blocks**

**Preparation of Parts**

-   Clean panel head and pocket beam, removing any epoxy.

-   Raise panel off table.

-   Drill all holes along pocket side (z = 0) and panel head to 7.3 mm.

    **Dry Layout**

-   Position both wire support blocks and all o-ring spacer beams.

-   Ensure that all o-ring grooves are properly aligned.

**Application of Epoxy**

-   Roll the glue (DP-460) on terminal block.

-   Roll a light coat of glue on panel head and pocket beam.

-   Put support blocks in place.

**Securing Wire Support Blocks**

-   Tap teflon rods into place, being careful not to break wire support
    rim.

-   Put release film over terminal block.

-   Add sandbags.