Preventive vs Predictive Maintenance

Preventive maintenance services machines on a schedule (time or usage); predictive maintenance services them when condition data says failure is approaching.

Preventive: every 30 days or every 250 run-hours — cheap to run, occasionally over-services. Predictive: vibration, temperature or oil analysis triggers work — precise, but needs sensors and baseline discipline.

The honest sequence for most plants: (1) reactive chaos → (2) time-based PM actually happening → (3) usage-based PM on the machines with meters → (4) predictive on the handful of critical machines where sensor cost is justified.

Skipping stages fails: predictive pilots die in plants that can't yet execute a monthly greasing schedule. Master run-hour based servicing first — it delivers 80% of the benefit at 5% of the sensor cost.