Summary of the meeting at CERN on EB welding for the PIMS, 11 June 2009

place: CERN, Switzerland

present: G. Favre, F. Gerigk, R. Kisiel, J. Kopec, T. Tardy

welding tests

• The last welding test (EDMS 995807) was discussed: It was confirmed that the test results are highly satisfying and that for the series production the welding depth should be increased from 7 to 8 mm to avoid virtual leaks.
• A new test was proposed one month ago, which includes an overlap area (see test description). Since then 3 new tests have been made and 2 samples (A and C) were presented at the meeting. Sample A was made in the same way as the 2nd test in order to test the weld shrinkage. Standard OFE copper was used and a shrinkage between 0.2 (edges of the piece) and 0.4 mm (center of piece) was found. In the "overlap" test these values were confirmed. At CERN a shrinkage of 0.2 mm was measured, which is probably due to the higher electron beam power yielding a thinner root of the weld. In the analysis of piece C it should be noted that the cathode of the electron gun broke down during welding step C (down slope in test description)
• The welding parameters for the tests were provided to CERN.
• It was suggested to use nitrogen to improve the cooling and to reduce the cool-down time of the pieces. It was also suggested to measure the temperature of the pieces right after welding.
• The power of the electron beam gun will be upgraded to 15 kW and it was suggested to make another welding test once this modification is done.

series production of the PIMS

• The Soltan institute received support from Brussels to upgrade the machine park of their workshop. It is planned to buy three numerically controlled machines, one of which will be a turning machine (large enough for the PIMS), and one will be a milling machine. It is exptected to purchase the machines in a time frame starting with the next quarter until the first quarter of 2010.
• A 2nd bid was made for the purchase of an electron beam welding machine. A decision is expected within the next months. If the bid is successful the new machine will be installed either in the institute in Warsaw, which has done the previous tests, or at the Soltan institute. In both cases the people operating the machine will be the same.
• CERN will provide the minimum dimensions of the welding chamber, necessary to do the welding of the PIMS.
• CERN will also prepare a list of the technological steps for the production of the PIMS, so that the Soltan institute can make a realistic cost estimate for the series production.
• Production is expected to start mid 2010, and should finish within 2 - 2.5 years.

-- FrankGerigk - 11 Jun 2009