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Citation |
Keller AZ, Kamath ARR, Perera UD. Reliab. Eng. 1982; 3(6): 449-473. |
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Copyright |
(Copyright © 1982, Elsevier Publishing) |
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DOI |
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PMID |
unavailable |
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Abstract |
A reliability and maintainability study of computer control (CNC) machine tools is described. For this analysis field failure data collected over a period of three years on approximately 35 CNC machine tools during their warranty period were analysed. In order to apply quantitative reliability methods, a coding system was devised to code failure data which were then collated into a data bank. The lognormal and the Weibull distribution were found to be applicable to describe time between failures and the repair times. The Duane reliability growth model arising from the introduction of modifications to improve machine tool performance gave a good fit to the observed reliability growth for a CNC system. For the hydraulic and mechanical systems, a damped oscillation of the Duane growth model is observed. |