1. Cost reduction activities in cavity fabrication at MHI
XR02560
Cost reduction activities in cavity fabrication at MHI
F. Inoue
K. Okihira, H. Hara, H. Hitomi,
K. Kanaoka, T. Yanagisawa, K. Sennyu
Nov. 2012
Advanced Mechanical Systems Department

2. 2. Improvement in cavity fabrication method for cost reduction
Contents
1. SRF activities at MHI
2. Improvement in cavity fabrication method for cost reduction
3. Cost analysis
4. Summary
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3. ’06~ ERL Cavity 9 sets ’90~ L-band Cavity ’02~ Crab Cavity 2 sets
1-1 SRF activities at MHI
’05~ STF Cavity 26 sets
’06~ ERL Cavity 9 sets
Courtesy of KEK
’90~ L-band Cavity
’02~ Crab Cavity 2 sets
‘86~ Tristan Cavity　36sets
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4. 1-2 Activities for Improvement of cavity performance
In case of KEK STF cavities
Cavity
No.
Assy.
Thickness
of thinning
Shape
of groove
Bead
condition
Frequency
of chemical
polishing
Management
of cleanness
High pressure gas safety law
1.0
#1-4
Horizontal
2.5 mm
Butt
Bumpy
Only after thinning
Air
duster －
1.5
#5-6
#7-9
2.0 mm
Smoother
Each step
(just before EBW)
　　Clean area
#10-11
Step
Flatter
2.0
#12-22
More stable
top
gun
Adapted
2-a
#23-26
Vertical
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5. 1-3 Recent result of vertical test for STF cavity
Under re-treatment
All these cavities are governing high pressure gas safety law in Japan.
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6. 2 Improvement in cavity fabrication method for cost reduction
List of our proposed fabrication methods
Applied to Production cavities;
・To simplify inner conductor of HOM coupler design
・Seamless beam-pipe (deep-drawing)
Applied to R&D cavities(MHI-A,MHI-B);
・Using LBW instead of EBW for stiffener and flange
・Automatic finishing for inner surface of cell
・Seamless dumbbell
Applied to R&D cavity(MHI-C);
・Welding the equator line in succession
・Using LBW for baseplate
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7. 2-1 Fabrication of MHI-A cavity
Feature
・Deep drawing for HOM cup.
・LBW for stiffener ring and flanges of beam tube.
EBW
nipple for tuning
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8. 2-2 Fabrication of MHI-B cavity
Feature
・ No welding seam on iris and longitudinal line.
・ Finishing for inner surface of dumbbell is auto buffing.
Seamless dumbbell
This cavity was developed by MHI and KEK,
and the VT will be carried out at JLab, soon.
Auto buffing
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9. 2-3 Fabrication of MHI-C cavity
Feature
・Welding all equator line of cavity in succession by vertical position
without purge of vacuum chamber.
・LBW for baseplate.
LBW
EBW
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10. 2-3 Welding in succession (MHI-C)
Before
Cavity was welded by horizontal position.
1 or 2 seams of equator are welded in one batch.
Welding procedure
1 cavity／5 batches
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11. 2-4 Welding in succession (MHI-C)
Cavity is assembled and welded by vertical position.
9 seams of equator are welded in one batch.
EBW
4 cavities／1 batch
EBW
EBW
EBW
EBW
future
EBW
EBW
EBW
EBW
EBW
1 cavity／1 batch
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12. 2-5 LBW for baseplate (MHI-C)
Welding Nb ring and Ti plate by LBW
Vacuum condition is not required.
Ti vapor is bad for EBW-gun.
- no problem by LBW with argon gas shield
LBW bead is equivalent to EBW.
- Mechanical strength is OK at room temp
- now under cold test at KEK
Base plate Ti Nb
End group
LBW
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13. 2-6 Application of fabrication methods
Now , STF #23 ~ #26 cavities are under fabrication.
Some fabrication methods will be applied to these cavities.
・Simple design for inner conductor of HOM coupler
・Seamless beam-pipe (deep-drawing)
・Using LBW for stiffener
・Using LBW for baseplate
・Welding the equator line in succession by vertical position
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14. 3 Cost analysis Next phase,
Cost analysis for a cavity without EP process
(100 cavities production)
(%)
Material
Mechanical
Machining
Welding
Inspection
Sub-total
Cavity
32.5
24.5
19.0
5.2
81.2
LHe jacket
4.7
8.0
2.4
3.8
18.8
Sub- total
37.2
21.4
8.9
100
Cost analysis for a cavity without EP process
(100 cavities production)
(%)
Material
Mechanical
Machining
Welding
Inspection
Sub-total
Cavity
32.5
24.5
19.0
5.2
81.2
LHe jacket
4.7
8.0
2.4
3.8
18.8
Sub- total
37.2
21.4
8.9
100
Cost analysis for a cavity without EP process
(100 cavities production)
(%)
Material
Mechanical
Machining
Welding
Inspection
Sub-total
Cavity
32.5
24.5
19.0
5.2
81.2
LHe jacket
4.7
8.0
2.4
3.8
18.8
Sub- total
37.2
21.4
8.9
100
Next phase,
we should reduce the cost of material & machining in corporation with KEK.
This phase
We got some good results for cost reduction of welding.
~40% welding cost reduction from prior method
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15. 4 Summary
We have supplied some 1.3GHz SRF cavities for STF and ERL projects at KEK for the last few years. The cavity performance are improving step by step.
We have proposed some ideas for cost reduction and these method was established step by step. We have estimated the effect of cost reduction.
For more cost reduction, we need some idea to reduce the volume of material & design for easy machining.
MHI-B cavity with seamless dumbbell will be transported to J-Lab for a surfacetreatment and vertical test.
MHI-C cavity is under inspection. It will be done a vertical test at KEK next month.
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16. E. Kako, K. Watanabe , S. Noguchi, T. Shishido and Y. Yamamoto at KEK
Special thanks
Special thanks to
E. Kako, K. Watanabe , S. Noguchi,
T. Shishido and Y. Yamamoto at KEK
for STF activities in this presentation
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17. Thank you for your attention !
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