1 mqxf workshop on structure, alignment, and electrical qa feb 2-4, 2016 options for modifications...

1MQXF Workshop on Structure, Alignment, and Electrical QA Feb 2-4, 2016 Options for modifications to parts and procedures

Options for modifications to parts and procedures

M. AnerellaFebruary 3, 2016

representing work by J. Schmalzle, P. Kovach

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“Se non è vero, è ben trovato”


Goals

1. Improve quality

2. Reduce assembly labor costs / time

3. Reduce material costs


candidates

1. Improve closure procedure of reaction & impregnation fixtures2. Build solid impregnation fixture formblocks3. Improve coil instrumentation wire splice design4. Utilize stamped lamination collars, pads, yokes5. Provide additional space for tuning shims (in collars and/or pads)6. Remove bolts from collars & pads7. Eliminate masters8. “tune” aluminum support shells to reduce coil stress variations

along the axial direction9. Utilize full length keys, bladders10. Utilize extruded bladders11. “four-fold” bladder pressurization


• Goal – maintain parallelism of fixture during bolting procedure• Present (FNAL/CERN) method – bolt fixture halves to shim(s) first, then unbolt,

remove shim(s) and perform final bolting— Additional bolting step takes extra time/cost for both R&I assemblies of every coil— Parallelism of final closure is still not guaranteed at final bolting

1. Improve impregnation fixture closure procedure

Alternative →Bolt fixture using incremental torques applied simultaneously to both fixture sides & measure incremental gaps at each torque step to ensure parallelism

gapgap


2. Build solid impregnation formblocks

Replace top plate and EDM blocks with solid formblocks, 4.2 m long (Q1/Q3) sections, machined & honed

0-ring seal to base plateMandrel blocks remain unchanged (50 mm EDM)

Simplified solid tool

Liner is eliminated

Side bars and screws are eliminated

Pusher bars and screws are eliminated

Top plate is eliminated

* All changes improve tolerance and reduce cost *

Mating surface is maintained to retain compatibility with reaction fixture plate

Impact to present design

• Vendor quote for 4.6 m sst part is $114K each

• Can recycle existing fb’s for reaction fixtures

• Reduces cleaning, prep time w.r.t. EDM blocks

Existing solid

RHIC 10m coil

tooling


• Simplified wiring procedure – G11 fillers with windows for making wire connections:

• Eliminates need to package short wires inside impregnation fixture.

• Eliminates need to extend short wires after impregnation

3. Improve coil instrumentation wire splice design (I)

G11 Fillers

Teflon Inserts

Procedure before impregnation:• Position trace in wiring pocket.• Install G11 filler over trace.• Install Teflon inserts in wiring

windows.


Wires soldered

Procedure after impregnation:• Remove Teflon inserts.• Solder wires to trace.• Fill windows with epoxy putty.

→ provides strain relief for solder connections

Epoxy Putty. (tried also blue Stycast epoxy – more difficult to fill work with. Putty is easy to apply and smooth flush)

3. Improve coil instrumentation wire splice design (II)


4. Utilize stamped lamination collars, pads, yokes

1. EDM parts are expensive & relatively hard to fabricate to required tolerances

2. Stamped laminations reduce cost, increase accuracy3. EDM / solid parts can be used in select areas where needed

(yoke fiducials, etc.) as outlined by CERN


• No compromise to structural integrity, function; Collar – Pad loading surfaces unaffected

• Elimination of bolts (#6) provides significant opportunities for magnetic shimming in collars, pads

• Elimination of masters (#7) provides significant opportunity in deeper bladder slots in pads, yokes

5. Provide space for tuning shims (in collars/pads/yokes)

Additional Magnetic Shimming

iron

iron

iron

iron

iron

iron

iron

iron

= new / increased magnetic shim locations


6. Remove bolts from collars & pads1. Bolted collars are time consuming to assemble & result in an assembly that is

difficult to maintain proper shape (see results presented at Structure Review; 10 mils smaller at bottom than at top)

2. Full length closure of keyed collars* prevents separation from coil key due to Lorentz forces, improves alignment

* note: assumes “LARP-style” of assembly.3. Bolted pads may be eliminated in conjunction with eliminating masters (see #7)

Stamped aluminum collar laminations:• Single part for all lams• Critical features stamped• Closure features

machined on 1 surface• Eliminates the need for

accurate pinning or welding

Tapered phosphor bronze collaring keys:• 6 degree included angle

(self locking)• Easily installed by hand or

light tapping, self locking• ~ 1 mm shorter than

keyway, allows ~ 0.2 mm adjustment in collar closure against coil key if needed

Helium flows freely from holes in coil pole keys through gaps between laminations


7. Eliminate masters (I)

Masters are eliminated.

Bladders / load keys are installed between yoke and load pads.

Pads locate to collars at angled surfaces (as masters did 2x)

Pads key directly to yokes

Revised QXF magnet cross section


7. Eliminate masters (II)

Load pads are pre-assembled in the yoke shell subassembly

Temporary, intermittent bolts secure load pads in retracted position.

Bolts are installed only at existing cutouts at ends of shells.

Yoke-Shell subassembly now includes pads


7. Eliminate masters (III)

Collar assembly supported on roller assemblies, roller tracks inserted in yoke holes

Once collar assembly is in place, pad retention screws are removed and in their place jacking screw assemblies used to push pads into position against collars to increase space for bladder installation. Note: requires holes in table base at bottom screw locations

Cheaper insertion rail concept if desired; simpler support bar sliding on low friction UHMW bar.

Collar Pack Insertion

Jacking screw thread region


• Cutouts for yoke fiducials at each shell end causes increased deflections, ~20 MPa coil stress variation at those locations

• Compensating axial grooves in shell centers can eliminate variations, increase assembly tolerance margins

8. “tune” aluminum support shells to reduce coil stress variations along the axial direction


9., 10. Utilize full length keys, bladders,Utilize extruded bladders

4.2 m (Q1/Q3 full length) keys, bladders:

• Easier to pull (and push if needed) for insertion as well as removal

Extruded bladders:• Less susceptible to leaks by virtue of elimination of seam welds • Maximum displacement > 5 mm • Load is not reduced with increasing pressure (i.e., surface area is constant)• Works with backing bar as in present QXF bladder• For test, formed out of tube. For production, buy extrusion & flare ends• Pressurized to 8000 psi (55 MPa), achieved 6.3 mm travel without problem.

Assembly & test fixture Tested bladder

Forming tool


11. “four-fold” bladder pressurization

• Symmetric bladder / key loading at assembly eliminates shear on G-10 keys, improves final alignment after assembly

• 4 x more incremental pressures (i.e. smaller steps) ÷ 4 locations shimmed at each step results in: — equal ease of installation— similar assembly times


Bonus Candidates for consideration

Coils:• Eliminate curing of outer layer; install directly into reaction fixture• Eliminate inner trace

Structure:• Eliminate “Fuji film” inspection assembly


Thank you for your attention


Appendix

Formblock Fabrication Steps


Step 1 – initial milling of tooling halves & drilling holes*

* some used for temporary bolting together of halves


Step 2 – bolt halves together & gun drill to undersized radius


Step 3 – separate and machine each half to larger undersized radius, accurately machine midplane

and machine overall height


Step 4 – bolt halves together and hone radius to final dimension

Ø ± 0.013 mm


Ref - QXF Baseline Design

1 mqxf workshop on structure, alignment, and electrical qa feb 2-4, 2016 options for modifications...

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