An optimum maintenance strategy for a vertical boring machine system

The failure pattern of a costly vertical boring machine system, a repairable system, was adequately modelled by NHPP (Non-Homogeneous Poisson Process) with time dependent peril rate characterised by a Weibull intensity function. Having found the machine in a deteriorating or sad system, an optimal minimal repair preventive maintenance policy was worked out in terms of the number of intervening minimal repairs within an overhaul cycle by making use of the fitted NHPP model and minimising the total system cost per unit in an overhaul cycle with given overhaul package.