Fabrication and evaluation of HDDS cells

Dec. 10—12, ISG9, KEK

T. Kume, KEK(Presented by T. Higo)

Mechanical evaluation of HDDS cells and

estimation toward HDDS1 (H60VG3S18)

HDDS1 Machining procedure 1/3

1. Cut (logging)2. Rough cut (turning)– finish allowance of 0.2-0.5 mm

3. Anneal– at 500oC, 2 hours by N2 substitution or vacuum furnace

4. Machine tuning holes (drilling)5. Finish OD (turning)– with a soft jaw

6. Semi-finish cup side & finish nesting ID (turning) – with a collet chuck (tong hold of ~3 mm)– constant circumferential speed (2000 rpm, 20-30 m/rev)– one-stroke-turning for ellipse & cup end– start cutting from the ellipse top (2a)– semi-finishing with an allowance of 20 m on end surface– Finish inside cup

HDDS1 Machining procedure 2/3

7. Semi-finish disk side & finish nesting OD (turning)– with a collet chuck (tong hold of ~7 mm)– check the deflection of the disk end (< 4 m)– constant circumferential speed (2000 rpm, 20 - 30 m/rev)– start cutting from the ellipse top (2a)– semi-finishing with an allowance of 20 m

8. Dimension check9. Milling– 8o relief angle of milling tool(R0.5-flat <12o)– large radius of tool path (R2 and 2b <5o)

10. Finish cup side (turning)– finish end surface

11. Stamp the number on the disk side

HDDS1 Machining procedure 3/3

12. Finish disk side (turning)– same as “10” but together with the elliptical part

13. Clean & check dimensions

14. Ultraprecision turning of the both end surfaces – at KEK

Fabrication status

Quality estimation on HDDS cell fabrication in studying test cells for following two cases

1. HDDS0

dia. 45mm 6 replacement cells for H60VG3N

2. HDDS1

dia. 61mm H60VG3S18

Measurement positionsfor turning evaluation –radial direction

Turning error-radial direction(samples: HDDS1-052-1,2,4 for cutting test)

Tolerance: +/-0.02 mm

Accuracy: +/-0.01 mm

Repeatability: +/-0.005 mm

Limited by accuracy of lathe

0.0

1.0

2.0

3.0

4.0

5.0

6.0

-0.03 -0.02 -0.01 0 0.01 0.02 0.03

ODNest-ID2a2a+0.1(disk side)2a-0.1(cup side)2b

Error (mm)

Measurement positions

for Turning evaluation -axial direction

Turning Error-axial direction(samples: HDDS1-052-1,2,4 for cutting test)

Tolerance: p +/-0.01 mm

t +/-0.02 mm

Accuracy: +/-0.02 mm

Limited by operator skill, caused by scratch correction after finish

0.0

2.0

4.0

6.0

8.0

10

-0.03 -0.02 -0.01 0 0.01 0.02 0.03

tp

Error (mm)

Measurement positions for Milling evaluation

Milling Error(samples: HDDS1-052-1,2,4 for cutting test)

0.0

2.0

4.0

6.0

8.0

10

12

-0.03 -0.02 -0.01 0 0.01 0.02 0.03

hHOM

Error (mm)

Tolerance: h +/- 0.02 mm

HOM +/-0.05 mm

Accuracy: ~0.02 mm

Repeatability: ~0.005 mm

h: Caused by work alignment error

HOM: tool diam.

Angle measurement positions

r=2r=b

r=b

r=b- del ta

l i ne

3deg

Sepa

r at i

on

Mi l l i ng tool path

Milling tool path Intersection between 2b and r2

Escape circle radius 2mm for HDDS0 (45mm dia.)

9mm for HDDS1 (61mm dia.)

2b – r2 Typical in HDDS0

Angle between R2 and 2b(samples: HDDS0-026-0, 7 for RF test,

and HDDS0-026-1 for SLAC)

0.0

1.0

2.0

3.0

4.0

5.0

0 5 10

Angle (deg)

Tolerance: <= 5 deg

Results: 5-11 deg

Caused by work alignment error and tool path along an escaping circle with radius 2mm

Shift to escaping circle radius at 9mm for HDDS1, close to “b”.

R0.5—flat tool

Milling radius tool for HDDS0

Tool reliaf angle was changed to 8 degrees for HDDS1

In case of HDDS0Too severe depth control to get rid of edge mark at end of 3 degree wing

Escape towards less cutting (floating) side

Crossing at circular part

Uncontrollable crossing angle

Between flat surface to r0.5mm rounding

R0.5 – flat shape in HDDS0RF test cell #7 cup side

Elliptical

Slot end point

R0.5

Angle between R0.5 and flat(samples: HDDS0-026-0, 7 for RF test,

and HDDS0-026-1 for SLAC)

0.0

1.0

2.0

3.0

4.0

5.0

0 4 8 12 16 20 24

cup sidedisk side

Angle (deg)

Tolerance: <= 12 deg

Caused by tool positioning (axial) error , relief angle of the tool (3 deg), and correction turning after finish against scratch

Change relief angle to 8 deg for HDDS1

Elliptical shape and connectionRF test cell #7 cup side connection

2a top

Elliptical to flat

Angle between ellipse and flat end(samples: HDDS0-026-0, 7 for RF test,

and HDDS0-026-1 for SLAC)

0.0

1.0

2.0

3.0

4.0

5.0

0 1 2 3 4 5

cup sidedisk side

Angle (deg)

Tolerance: <= 1deg

Results: 1-3 deg

Limited by accuracy of lathe and/or additional flat-part cut without continuous cutting to elliptical part

For HDDS1, require continuous cutting between flat part and elliptical part

Turning roughness

Elliptical shape Ry=1.7trace due to tool shape?

Flat part Ry=0.5

RF test cell #7 cup side

Roughness of the turned surface(samples: HDDS0-026-00, 0, 7 for RF test,

HDDS0-026-1 for SLAC,HDDS1-052-4 for cutting test)

Tolerance: Ry 0.7 m

Roughness: ~0.6 m (straight, 1D), ~1.6 m (curve, 2D)

Difference of ~1.0 m is caused by tool periphery shape

0.0

1.0

2.0

3.0

4.0

5.0

0 0.5 1 1.5 2

Straight (1D) turning-cup endStraight turning-disk endCurve (2D) turning-cup sideCurve turning-disk side

Ry roughness (m)

0.7

Milling roughness

Roughness Ry 1.6m

Wave 3m/2mm

Slot end turning point with r=1.1mm

Roughness of the milled surface(sample: HDDS0-026-7 for RF test)

0.0

1.0

2.0

3.0

4.0

5.0

0 0.5 1 1.5 2

Milling-side cutMilling-face(R) cut

Ry roughness (m)

Tolerance: Ry 1 m

Results: 1.3-1.9 m

(seems to be) caused by tool mark

Disk flatness(samples: HDDS1-053-1,2 and

HDDS1-052-1,2,4 for cutting test)

Tolerance: 2 m

More than 30 pts by CMM

Result: 1—3 m

(seems to be) limited by lathe accuracy and deformation due to chucking and turning0.0

1.0

2.0

3.0

4.0

0 0.001 0.002 0.003 0.004 0.005

Turning onlyCompelete machining

Flatness (mm)

Cup-side flatness(samples: HDDS1-053-1,2 and

HDDS1-052-1,2,4 for cutting test)

Tolerance: 2 m

More than 30 pts by CMM

Result: 2—3 m

(seems to be) limited by lathe accuracy and deformation due to chucking

(“Turning only” is with copper without annealing)

0.0

1.0

2.0

3.0

4.0

0 0.001 0.002 0.003 0.004 0.005

Turning only

Compelete machining

Flatness (mm)

Parallelism between disk and cup (samples: HDDS1-053-1,2 and

HDDS1-052-1,2,4 for cutting test)

Tolerance: 5 m

Result: 2—5 m

(seems to be) limited by lathe accuracy and chucking

0.0

1.0

2.0

3.0

4.0

0 0.001 0.002 0.003 0.004 0.005

Turning onlyComplete machining

Parallelness (mm)

Conclusion to make H60VG3S18

•Mechanical dimension: OK within tuning range

•Junction angle: should be OK

•Surface finish: Acceptable

•Surface flatness: Improve with diamond turning at KEK