IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Vacuum Science & Technology Monday Sessions
       Session VST-MoP

Paper VST-MoP12
Estimation of UHV Ball Bearing's Wear by Spectra Analysis of Residual Pressure

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Developments in Vacuum Technology Poster Session
Presenter: V.V. Gerasimov, Bauman Moscow State Technical University, Russia
Authors: E.A. Deulin, Bauman Moscow State Technical University, Russia
V.V. Gerasimov, Bauman Moscow State Technical University, Russia
A.G. Peressadko, Bauman Moscow State Technical University, Russia
Correspondent: Click to Email
The aim of this work is to show correlation between mechanical and vacuum parameters of UHV feedthrough and it's reliability.@footnote 1@ The variation of torque M, outgassing flow in dependence of working cycle's number was investigated. This experiment was carried out on experimental UHV installation with parameters: residual pressure P=7*10@super -5@ Pa, volume of vacuum chamber V=32 l, pumping speed S=150 l/s. The subject of research is a typical ultrahigh vacuum (UHV) mechanism - rotation motion feedthrough. It uses three ball bearings working in UHV. The ball bearings of stainless steel with and without Pb coverage were tested. The analyzed rotary feedthrough was rotating with speed 200 rpm. The diagnosing signals M and Q were storaged every 2000 revolutions of the shaft. The criteria of failure was the achieving by own torque the level of 2 N*m. The correlation level of an average torque M@sub a@, and the maximum torque M@sub max@ parameters with another ones (Q - summarized outgassing flow, Q@sub 1@ - the spectral power of base frequency) was analyzed. The results show that the longevity of feedthrough based on M@sub max@ parameter with ball bearings covered Pb was 170*10@super 3@ of working cycles. The average outgassing flow Q for them was about 1*10@super -4@ torr*l/s. The longevity of feedthrough based on M@sub max@ parameter with ball bearings without coverage was 33*10@super 3@ of working cycles. The average outgassing flow Q for them was about 1*10@super -5@ torr*l/s. During experiment it was shown that the outgassing flow had a periodical charater. The results show that the amplitude of Q@sub 1@ had a good correlation with M@sub max@, that's why we could choose it as one of the main diagnosing parameter. @FootnoteText@ @footnote 1@A.Toy., Control and diagnostics can improve your vacuum, if you know your needs., Semiconductor International., October 1989, pp. 61-63.