A parameter estimation method for machine tool reliability analysis using expert judgement

This paper aims at providing a parameter estimation method for the machine tool reliability analysis to overcome the problem of unavailability of a well-defined failure data collection mechanism. It uses the knowledge and experience of maintenance personnel to obtain the parameters of lifetime distribution of the repairable as well as non-repairable components/ subassemblies. It is further developed for the cases where the knowledge available with the expert is with reference to the preventive repair/replacement policy used in the field. In case of imperfect repairs, the methodology also helps in estimating the value of restoration factor. The goodness of the proposed methodology at a given accuracy level in expert judgements are tested against the maximum likelihood estimates of the parameters. It is concluded that the expert judgement method provides a satisfactory alternative to statistical methods when no or very few historical time to failure data points are available.