In this paper, condition-based Preventive Maintenance (PM) approach is used for a Computer
Numerical Control (CNC) turning machine .Wearing of CNC machine is based on the various
machining conditions (such as cutting speed, feed and depth of cut) and the time for which it is
being used. Larger value of machine power and production rates usually results in more wear
and failure of CNC machine. The various machining conditions of CNC machine usually affects
the PM requirement. Higher production rate usually results in greater deterioration of the machine,
and hence there is a need of frequent preventive maintenance of the machine. In this paper, we
adopted the methodology of PM approach to determine the preventive maintenance index function,
using the values taken from a CNC machine, to determine the exact time needed between the
2 PM visits, which in turn can help in reducing the frequent breakdowns occurring in the CNC
machine