Preventive maintenance consists of routine actions taken a planned manner to prevent breakdown and to ensure operational efficiency to the extent it is economically and practicably possible. In preventive maintenance periodic inspection is carried out to anticipate breakdowns and to prevent them before they occur instead of allowing the breakdown to happen and then to take action. The underlying principle is prevention is better than cure. Therefore for adopting preventing maintenance policy one must have the data showing the frequency with which machines have maintenance free performance for a given number of operating hours ( i ,e, breakdown time distribution ) from this data the preventive maintenance period for each machines or a group of similar machines can be set properly. The main objective of preventive maintenance is to prevent breakdown and to ensure operational accuracy and safety.