Traditionally, preventive maintenance (PM) is structured for X tasks to be performed at Y intervals. Cleaning and calibrating are common PM activities.
Calibrating involves taking a measurement; If it’s out of spec, you adjust the equipment to bring it back in spec. Mission accomplished, and you move on. What is left out is a determination of why the equipment was out of spec and whether that means anything in a predictive sense.
Economists look at “leading indicators” to predict where the economy is heading. Some types of events influence the economy several weeks or months after they happen. You can, and should, use this principle for maintenance.
For example, consider the contacts on a breaker. If, during your PM, you find excessive pitting just as you did on the previous PM for this breaker, then that’s significant. That repeated problem is a leading indicator that the mean time between failures (MTBF) is going to be abnormally short.
For critical equipment, consider creating reports in your CMMS where you include parameters so that the CMMS will automatically identify leading indicators. For other equipment, simply have a checkbox on the PM form and rely on individual judgment.
