Breakdown Maintenance (BDM)

According to Murphy, if a machine can fail, it will. Hence no machine is completely immune to failures. Every machine experiences the breakdown on some day or other even no matter how carefully, it is run according to its specifications and ambient operating conditions. These breakdowns may occur due to UNPREDICTABLE failures or GRADUAL WEAR AND TEAR of the machine parts.

In the event of such failures, breakdown maintenance policy is usually adopted. When the continuous running of machines is not compulsory or on those machines which do not affect any production flow due to the shutdown, this policy is suitable. In general practice this policy is adopted in combination with preventive maintenance.

The Break Down Maintenance work starts on the machine from the moment it fails and ends when it is repaired and handed over to the production personnel (i.e. Machine is put under use). Except the normal lubrication and cleaning this system is no way concerned to prevent the occurrence of the breakdown but gets alert when the breakdown has occurred. Hence in most of the cases this system reduces the machine utility directly and indirectly and thus results in low machine efficiency because this type of maintenance usually takes a long time to repair.

The moment the machine fails it is said to be in DOWN condition. When the machine is repaired, i.e. when the machine is put into operation, it is said to be in UP condition. The time taken between any two consecutive failures, i.e. from the moment a machine is kept in use (UP) to the moment it next fails, is called the 'Time Between Failures' or TBF. The time taken to repair and put it into use (up condition) is called 'Time To Repair' or TTR.