# Presentation: 215296

## STATUS OF DEVELOPMENT 1.3 GHZ TESLA CAVITY TOOLING AT RRCAT, INDORE Fermi-India Monthly Review Meeting20th March, 2008Rajeshwar S. Sandhaon behalf of the team from RRCATRRCAT, INDORE

## IMPORTANT FEATURE OF FORMING TOOLING

_**IMPORTANT FEATURE OF FORMING TOOLING**_
**Profile tolerance on half cell****	****: 0.2 mm ****1,2**
**Reference  Drawing DESY 1.3 GHZ TESLA RF CAVITY MID HALF CELL Number - 4904.010-MD-439156**
**	****LONG END CELL Number - 4904.010-MD-439155**
**	****SHORT END CELL Number - 4904.010-MD-439163**
**DESY Specification of welded Superconducting resonators **
**	****for TTF-FEL;  D. Proch - MHF-SL  1-1999 Version A**
- As per the specifications, the acceptable tolerances are ±0.2 mm for contour change of the half cells

## 	MID HALF CELL Drg. No - 4904.010-MD-439156

- DESY SPECS WELDED 1.3 GHZ SC RESONATORS FOR TTF-FEL; D. PROCH, MHF-SL 1-1999 Version A
- 13.11 Cavity contour, frequency and length ......... the acceptable tolerances are
-   0.1 mm for weld shrinkage,
-   0.2 mm for contour change of the half cells

## PRESENT STATUS OF MANUFACTURING

| Cell Type | Set I 
For Trials | Set II
For Fermilab | Set III
For TRIUMF | Set IV
For RRCAT |
| --- | --- | --- | --- | --- |
| Center cell Tooling | Qualified for forming and machining fixture,  | Machining completed, 
Forming trials completed. Forming tooling ready for dispatch to Fermilab | Not started | Not Started |
| Long End cell Tooling | First iteration of forming using copper blanks completed, results being studied | Not Started | Not Started | Not Started |
| Short End cell
Tooling | Final contour of tooling  prepared and digitized | Not Started | Not Started | Not Started |

## Account of work done

- Contour development based on inspection of previous forming: Final geometry in three iterations of forming, measuring, redeveloping profile, machining, ...
- Difference observed in formability of Al and OFE copper.
- OFE copper blanks are being used for tooling qualification, Al blanks for initial trials
- Now using copper for reference as given in DESY specs.
- Deep drawn cups follows punch profile closely except in the elliptical region
- Improvement in Half cell fixturing for machining and CMM inspection. Optimisation of CMM Inspection cycle,
- Problem observed in Trimming operation- height variation in a half cell – Modification in fixture design- Under machining
- CC forming tooling completed, LC under work

## QUALIFIED CENTER CELL TOOLING FOR DEEP DRAWING 

**QUALIFIED CENTER CELL TOOLING FOR DEEP DRAWING**** **

## LONG END CELL FORMING TOOLING SHOWN TO ILC TEAM 

**LONG END CELL FORMING TOOLING SHOWN TO ILC TEAM **
**DURING THEIR VISIT TO RRCAT**

## FORMING TRIALS TO QUALIFY LONG END CELL 

**DONE ON 17 March 2008**
**Trimming and CMM inspection of deep drawn cups in progress **

## ISSUES INVOLVED IN TRIMMING

- Half cells are trimmed on equator and iris faces using machining fixture (to use the profile surface as reference)
- Variation in height of half cell (measured at 8 locations equally spaced) was observed as typically:
- Maximum variation in Single Cup – 0.27 mm (max);
- Minimum variation in Single Cup –0.19 mm (min)
- Variation in Four cups  - 0.34 mm
- Matter is being investigated to reduced the extent of height variation of finished cups

**ISSUES INVOLVED IN TRIMMING**

## TRIMMING OF HALF CELL EQUATOR REGION USING 

**TRIMMING OF HALF CELL EQUATOR REGION USING **
**MACHINING FIXTURE DEVELOPED AT RRCAT**

## From: Mike Foley [mailto:foleymh@fnal.gov] Sent: Wednesday, February 27, 2008 3:28 AMTo: Jishnu Dwivedi  Cc: Shekhar; rssSubject: Re: Cavity Tooling Development.

Hello Jishnu,
Thank you for the report and the pictures.  One of our vendors has  also experienced the problem you mentioned, only to a much greater  extent.  They are still trying to solve the problem.
We have not experienced that problem when machining 3.9 GHz half- cells to length.  However, the fact that the 3.9 GHz half-cells are  so much smaller, and the profiles have more extreme curvature,  probably helps us.
Mike

On Feb 26, 2008, at 7:52 AM, Jishnu Dwivedi wrote:
> Dear Mike,
>     This is an update. We were able to form 1.3 GHz Centre Cell cups  within a tolerance of 0.2 mm. We found the forming behavior of copper  is aluminum is different and copper gives less deviation from the  punch profile (we used annealed OFE copper C-10100 and annealed  aluminum AA 1100 2.8 mm sheets).
>     The machining fixture needs some design change as the trimmed cups  have a height difference of about 0.3 mm. This is due to the fact that  the formed cup is not held uniquely in the fixture. The held position
> of cup (to be trimmed) changes during tightening (due to relative  movement). Also during initial placement of male and female parts of  the fixture, any sliding (resorted to  to centre the pieces) slides  the cup. We are doing some design changes in a bid to over-come the  problem. Hence there is some delay. We will be able to send to you the  centre cell tooling by mid of March 2008. If you have any comments on  the problem we have seen on the machining fixture kindly let us know. 

 Some photos and status of the work is attached.

 Best regards,
-Jishnu

- Hello Jishnu,
- Thank you for the report and the pictures.  One of our vendors has  also experienced the problem you mentioned, only to a much greater  extent.  They are still trying to solve the problem.
- We have not experienced that problem when machining 3.9 GHz half- cells to length.  However, the fact that the 3.9 GHz half-cells are  so much smaller, and the profiles have more extreme curvature,  probably helps us.
- Mike
- On Feb 26, 2008, at 7:52 AM, Jishnu Dwivedi wrote:
- > Dear Mike,
- >     This is an update. We were able to form 1.3 GHz Centre Cell cups  within a tolerance of 0.2 mm. We found the forming behavior of copper  is aluminum is different and copper gives less deviation from the  punch profile (we used annealed OFE copper C-10100 and annealed  aluminum AA 1100 2.8 mm sheets).
- >     The machining fixture needs some design change as the trimmed cups  have a height difference of about 0.3 mm. This is due to the fact that  the formed cup is not held uniquely in the fixture. The held position
- > of cup (to be trimmed) changes during tightening (due to relative  movement). Also during initial placement of male and female parts of  the fixture, any sliding (resorted to  to centre the pieces) slides  the cup. We are doing some design changes in a bid to over-come the  problem. Hence there is some delay. We will be able to send to you the  centre cell tooling by mid of March 2008. If you have any comments on  the problem we have seen on the machining fixture kindly let us know.
-  Some photos and status of the work is attached.
-  Best regards,
- -Jishnu

## Modification in Machining Fixture

_**Modification in Machining Fixture**_
- (under machining)

## MACHINING OF MODIFIED MACHINING FIXTURE

**MACHINING OF MODIFIED MACHINING FIXTURE**

##      HALF CELL BEING INSPECTED USING TEMPLATE 

**     ****HALF CELL BEING INSPECTED USING TEMPLATE **

## RESULT OF PROFILE INSPECTION OF SECOND COPPER HALF CELL AFTER TRIMMING  TO FINAL LENGTH (57.7 MM)

## Slide 16

## Stacked half cells

**Stacked half cells**

##      HALF CELLS TRIMMED ON BOTH FACES

**     ****HALF CELLS TRIMMED ON BOTH FACES**

## Future work and schedule-

** ****Shipment of one set of center cell – half cells****	****	****: March 2008**
** ****Shipment of one set of center cell tooling to Fermilab****	****: March 2008**
**      ****(for comments**)
**  ****Incorporation of Fermilab comments****	****	****	****: March  2008**
**  ****Shipment of one set of complete tooling to TRIUMF****	****: April 2008**
**  ****Shipment of one set of complete tooling to Fermilab****	****: May 2008**

## Thank you for your attention