Condition-based maintenance (CBM) relies on collecting data from machinery to determine maintenance needs. It is similar to predictive maintenance because it relies on collecting data from equipment to determine what maintenance activities to carry out. Time-based maintenance (TBM), also known as ‘planned maintenance’, depends on maintaining equipment at regular intervals or at times that are planned in advance.
The timing may be determined by guidelines from the machinery manufacturer, set according to the level of usage of the equipment, or even predicted based on anomalies in data collected from the machinery (time-based maintenance can be part of both a preventative maintenance and a predictive maintenance regime).
CBM means monitoring the current condition of machinery using diagnostics equipment such as sensors, measurement devices, and data collectors. Maintenance actions are determined based on the observed condition of equipment or the crossing of predetermined thresholds.
In practice, condition-based maintenance must be balanced with time-based maintenance. If time-based maintenance has already proven to be effective in preventing breakdown of machinery, then installing the networks of sensors necessary for condition-based monitoring may be unnecessary and expensive.