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**Procurement Plan for the ATLAS Pixel Detector Disk Support Ring**

**William O. Miller, W. K Miller**

September 19,2001

  ------------- --------------- ------------------------- ----------------
                Name:           Phone & E-Mail            Signature:

  Main Author:  William O.                                
                Miller                                    

  Approved:     William O.                                
                Miller                                    
  ------------- --------------- ------------------------- ----------------

**Abstract**

This document outlines the procurement plan for the subject composite
ring, which is used to support an array of 8-pixel disk sectors. This
plan covers the fabrication and inspection tasks, as well as the
fixed-price cost associated with each discrete phase.

Revision Log

  ---------- --------------- --------------- -----------------------------------
  **Rev.**   **Date**        **Author(s)**   **Summary of Revisions/Comments**

  \-         Month date,                     Initial release.
             year                            

                                             
  ---------- --------------- --------------- -----------------------------------

Table of Contents

***1. Introduction [4](#introduction)***

2\. Work Statement [4](#work-statement)

2.1 Phase 1-*Fabrication of Qualified C-Channels for Phase 2*
[4](#phase-1-fabrication-of-qualified-c-channels-for-phase-2)

2.2 Phase 2-*Fabrication of Ring Component Parts and Qualification of
Pre-Production Ring*
[4](#phase-2-fabrication-of-ring-component-parts-and-qualification-of-pre-production-ring)

2.3 Phase 3- *ATLAS Pixel Detector Production Disk Support Rings*
[5](#phase-3--atlas-pixel-detector-production-disk-support-rings)

3\. Costs [5](#costs)

4\. Preliminary Assembly and Inspection Procedure
[5](#preliminary-assembly-and-inspection-procedure)

4.1 Inspection Figures [9](#inspection-figures)

5\. References [12](#references)

# Introduction

It is desired that the ATLAS Pixel Detector Disk Support Ring XXX
production be accomplished in three phases. The first phase is concerned
with setting the appropriate "toe-in" dimensions for the matched metal
mold used to fabricate the ring C-Channels. The second phase is the
assembly of a pre-production ring, which is used to qualify part
acceptance. This phase confirms the quality of all tooling to be used in
the final production of 6-disk support rings. Phase 3 is concerned with
the production of 6-rings, which are delivered to the ATLAS Pixel
Detector Project

# Work Statement

## Phase 1-*Fabrication of Qualified C-Channels for Phase 2*

The vendor shall: (1) procure the necessary materials, and (2) fabricate
the matched metal molds for producing the C-Channels segments, inner and
outer, 2-each. Prior to molding the C-Channels, the molds will be
inspected by the vendor and the inspection records submitted to LBNL[^1]
for production approval. Vendor shall then mold and final machine sets
of 2-each C-Channels, 2 inner and 2 outer. The vendor shall: (1) inspect
the C-Channels, (2) recommend mold rework, if necessary, and (3) submit
this information with recommendations to LBNL. Based on concurrence with
LBNL the vendor shall modify, as required, the inner and outer mold
inserts to eliminate "toe-out" of the C-Channel skirts (within "toe"
limits prescribed in drawing ###).

After tool modifications have been accepted by LBNL, the vendor shall
produce once again 2-inner and 2-outer C-Channels for final evaluation.
After receiving approval from LBNL, vendor shall mold and final machine
complete sets of inner (4) and outer (4) C-Channels for the Phase 2,
pre-production ring.

## Phase 2-*Fabrication of Ring Component Parts and Qualification of Pre-Production Ring*

This phase consists of several parts: (1) fabrication of precision
bonding tooling and alignment jigs, (2) procurement of piece parts for
7-rings (exclusive of C-Channels), and (3) the assembly of one
pre-production ring. Procurement of ring piece parts is limited to
machining of the carbon-carbon ring face(s), and fabricating the sector
bushings and ring mount tabs. Vendor shall procure all piece parts in
phase 2 and thereby secure quantity pricing.

One pre-production ring shall be assembled using the C-Channels produced
in Phase 1. The vendor shall inspect the ring and submit the ring and
inspection records to LBNL for review. The vendor shall document all
modifications and or deviations to the assembly procedure that were
utilized in producing the pre-production ring.

## Phase 3- *ATLAS Pixel Detector Production Disk Support Rings* 

Vendor shall: (1) mold C-Channel sets for 6 rings, and (2) assemble
6-production rings using piece parts produced in phase 2, using the
assembly and QC procedures approved in Phase 2.

# Costs

The fixed costs for the three phases are as follows:

Phase 1: \$19025, limited to the effort described in task 2.1.

Phase 2: \$25276, for one completely assembled and inspected ring

Phase 3: \$63000; vendor reserves the right to re-bid this task if
modifications to ring construction are requested by LBNL following their
evaluation of the Phase 2 ring.

All materials and tooling fabrication are included in these costs with
the exception of the Carbon-Carbon plates necessary for producing the
ring facing. This material shall be provided by LBNL.

# Preliminary Assembly and Inspection Procedure

The vendor shall submit a procedure outlining the plans for assembly and
bonding of the ring prior to initiating the ring assembly in Phase 2.
This procedure will include dimensional inspection steps.

**Bond fixture (see Step 1 on sheet 7)**

1.  A mistress gage (fabricated by LBNL) using 5 pins is used to bond 3
    sector bushings at one time. The following steps are used to set the
    mating bushings in the graphite tooling plate.

2.  Mistress gage installs to the graphite plate from front using two
    3/16" dia. pins; the 3 brass bushings are installed and bonded from
    rear of plate. This is done to critically position the 3-bushing
    pattern to itself, and less critically to the other bushing
    patterns.

3.  Bonding bushings in graphite plate to critical tolerances will be
    done by Allcomp.

4.  *√* CMM Inspection of Graphite Bond Fixture with Bushings will be
    done by HYTEC. Approval required before proceeding.

**Face sheet #1 Alignment (See step 2, sheet 6)**

5.  Prior to bonding -- the graphite plate must be kept on a granite
    table during entire bonding process. Graphite plate inspected --
    dust, lint, dirt wiped and air-blown from surfaces.

6.  Face sheet #1 is placed on graphite plate, sheet 6. *√ A height gage
    will be used to determine that the face sheet is flat on the
    graphite plate --a inspection report will be filled out.*

7.  Face sheet #1 is angularly oriented on graphite plate using four
    0.281" gage pins. Use at least 3-0.281" pins for alignment (see step
    2 on sheet 6).

8.  *√ All C-Channels will be inspected and approved prior to
    incorporating them into a composite ring.*

**C-Channels bonded to Face sheet #1(See step 3, sheet 5)**

9.  Four C-channels are clamped to their aluminum clamping tools (same
    process as used before for the fabrication of earlier rings).

10. The C-Channel/Clamp assemblies are positioned in place using 3/16"
    gage pins. A dry run fit will be done with all C-Channels in place.
    C-Channels should be appropriately marked to match graphite plate
    (so they may be removed and replaced later).

11. *√ When dry run fit is complete, inspect using a height gage,
    measure and record the height of the top flange of all the
    C-Channels; determine that they all are coplanar (and at the correct
    height).*

12. All outer C-Channels and inner C-Channels are bonded in one setup.
    Sequentially place the C-Channels around ring circumference. After
    the Outer C-Channels bond adhesive is finished curing, bond the scab
    plates. This step is repeated for the inner channels. When bonding
    the C-Channels use a Caul plate to apply vertical force to the
    C-Channels. If Allcomp chooses to bond one C-Channel at a time,
    HYTEC requests notification of this change before proceeding.

13. Apply adhesive to both surfaces when bonding C-Channels (pre-test
    procedure to control adhesive overflow: note the face sheet's
    profile now falls short of C-Channel major/minor radius); do not
    remove this assembly from graphite plate to wipe away excess
    adhesive. If necessary use a hot-knife to remove excess adhesive
    after all ring bonding steps are complete.

14. Note there is less clearance between C-Channel flanges in this ring.
    Therefore it is recommended to remove the C-Channels clamp-nuts
    after each set of four are bonded in place - rather than trying to
    remove them all after the C-Channels have been bonded in place
    (remove the clamp nuts, but leave the pinned clamp in place to
    provide external support to C-Channel during bonding). Nuts for
    final channel are carefully removed at bushing scallop area.

**Install Face sheet #2 (see step 4, sheet 4)**

15. Install face sheet #2. Again 4X 0.281" pins angularly orient the
    second face sheet. Use at least 3- 0.281" pins for alignment.
    Control amount of adhesive used to prevent overflow.

16. Use the Caul plate to apply constant pressure on face sheet while
    bonding. \*Care must be taken with excess adhesive flowing out past
    face sheet and adhering to Caul plate.

17. *√ After Face sheet #2 adhesive has cured, run the height gage
    around the surface of face sheet #2(an indication of ring thickness)
    -- fill out inspection report.*

18. Mark orientation of ring on graphite fixture. Remove C-Channel
    clamps. Plug all C-Channel clamp holes with adhesive.

19. Remove ring and weigh ring.

**Install the mount tabs, 4 places. (See step 5, sheet 3)**

20. Install the ring on graphite fixture using previous angular
    orientation. Use height gage to verify ring position (compare to
    past data) and that it is flat on graphite fixture.

21. Do a dry fit of the Mount Tabs in position and constrained by the
    bond blocks. Note that each bond block has a number that corresponds
    with its correct position on the graphite fixture.

22. The critical alignment of the Mount Tabs is done using a 0.250"
    (thru graphite plate) and 0.125" pin (thru bond block); the bond
    block is positioned by two 0.187" pins (thru the graphite plate).
    The 0.250" dia pin positions the Mount Tab in X, Y; the 0.12" dia
    pin establishes the Z elevation for the Mount Tab.

23. The Mount Tabs should now be ready for bonding. First, the Mount Tab
    is pinned to the bond block then inserted into position. \*Care must
    be taken to prevent adhesive from getting into the 0.250" dia Mount
    Tab pin-hole (these 4X pin holes become a physical datum for the
    ring). See step 5 on sheet 3.

24. Once the Mount Tabs are bonded in position, remove the bond blocks.
    With the ring still pinned to the graphite fixture, insert four
    0.125" dia pins into the radial holes in the Mount Tabs. *√ Use a
    height gage to record the height of the 4 pins - fill out inspection
    report.*

25. Remove the composite ring shell from the graphite plate (remove
    0.250" dia pins). Weigh ring.

**Install 0.120" thru dia. Composite Ring Bushings**

26. Push 0.120" dia. pins into graphite plate bushings.

27. Install composite ring bushings on pins. \*Make sure no hair, lint
    or dust is in the counterbores of the graphite plate prior to
    installing bushings. Bushing surfaces should have been abraded and
    cleaned prior to bonding.

28. Push all bushings flat against counterbored surface.

29. *√ Use a height gage to record the height of all of the tops of the
    bushings relative to the graphite fixture face (all bushing heads
    should be coplanar) -- fill out inspection report.*

30. Apply adhesive on the ring facing just in the bushing area of
    contact (alternatively the bushing flange) and the bushing flange;
    now re-install composite ring shell atop bushings using correct
    orientation (see step 6 sheet 2).

31. *√ Use the height gage to make a cursory check-- across the surface
    of face sheet #2 to determine that the ring shell is flat against
    the graphite fixture -- fill out inspection report.*

**Bond Ring to Ring Bushings (See step 7, sheet 1)**

32. Put the caul plate on ring facing #2 and to apply force during
    bonding. Before placing the caul plate, inspect to see that no
    bushing vertical height has changed.

33. Do not remove ring assembly to remove excess adhesive; ring not to
    be removed until washers have been bonded in place.

**Install the Composite Ring Washers**

34. Bond the Composite ring washers on (see step 7 on sheet 1). The Caul
    plate may or not be used

35. *√ After washer adhesive is dr; use the height gage to record each
    washer height from the face of the graphite plate -- fill out
    inspection reports.*

36. Push the 24X 0.120" pins out through the back of the graphite plate,
    and remove the composite ring from the graphite plate.

37. Weigh ring.

**Inspect the Ring**

38. The ring will be inspected using a LBNL CMM inspection system. All
    hole positions and co-planar feature of the bushing heads will be
    determined. The 0.125" hole position of each Mount Tab will be
    determined. General dimensions to determine the "per print" ring's
    physical size will be taken.

## Inspection Figures

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![](media/image3.wmf){width="5.788194444444445in"
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![](media/image5.wmf){width="5.788194444444445in"
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![](media/image6.wmf){width="5.788194444444445in"
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![](media/image7.wmf){width="5.788194444444445in"
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![](media/image8.wmf){width="5.788194444444445in"
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# References

[^1]: Or a representative designated by LBNL