What is the key difference between predictive maintenance and preventive maintenance?

The key difference between predictive maintenance and preventive maintenance lies in how maintenance tasks are scheduled and performed. Preventive maintenance involves performing maintenance tasks at predetermined intervals, regardless of the actual condition of the equipment. These intervals are typically based on manufacturer recommendations, historical data, or industry best practices. Examples of preventive maintenance include lubricating equipment, changing filters, and inspecting components on a fixed schedule. Predictive maintenance, on the other hand, uses condition monitoring techniques to assess the actual condition of the equipment and schedule maintenance only when it is needed. Condition monitoring techniques include vibration analysis, oil analysis, thermography, and ultrasonic testing. By monitoring the equipment's condition, predictive maintenance can detect early signs of wear or failure and schedule maintenance before a breakdown occurs. This allows for more efficient use of maintenance resources and reduces the risk of unexpected downtime. Therefore, preventive maintenance is time-based, while predictive maintenance is condition-based.