The manufacturing process stops due to many unplanned event it accumulate in breakdown time. While breakdown time is most often related with equipment failures it actually encompasses any unplanned event that causes your manufacturing process to stop. For most manufacturers breakdown time is single largest source of production loss. The breakdown time may cause due to maintenance failure, operator mistake and machine failure. When managing machine tool maintenance a manufactuer must apply an proper decision technique in order to reveal hidden costs associated with production losses, reduce equipment breakdown time in an efficient and capable way and similarly identify the machine's performance. This paper presents a review of various causes of breakdown and it's effect on system which ultimately reduces the productivity from machine. As a result of the study, the critical rate of machine breakdown which affects the system has been determined.