Preventive Vs Predictive Maintenance

Machinery maintenance is an important part of any operation and identifying and preventing problems that may escalate into failure of the machines & equipment that leads to unplanned downtime. Maintenance can include a wide variety of practices such as periodic checks, servicing of the components, realignment of parts and even replacement of units/modules.

Preventive and Predictive maintenance are both classified as proactive maintenance strategies to help avoid equipment failure and unplanned downtime. Both preventive maintenance and predictive maintenance are designed to improve the reliability of the processes supported by the machines and increase the life & efficiency of the industrial assets. The difference between preventive and predictive maintenance is that preventive maintenance is scheduled at regular intervals while predictive maintenance is scheduled based on the asset condition. Either of these practices is better than a reactive maintenance, which focusses on maintenance post machine failure.

What is Preventive maintenance

Preventive maintenance is a program where equipment, tools, sensors, lubricants, etc. are checked and inspected at regular intervals. It is performed to prevent assets from unexpected failures. If an issue is found with the system, or if a component fails in operation, the maintenance team can respond quickly. For instance, expert technicians may grease up the bushings of a particular machine, at regular intervals or when specific parameters are set off; that is to say Preventive maintenance is undertaken as per a predetermined schedule.

Preventive maintenance is a simple process which is scheduled at intervals, irrespective of the failure identification. It largely depends on factors such as industry practices, experience, past failure analysis, and recommendations from Original Equipment Manufacturers (OEM).

It is also a sub-optimal process as the activity is based on a schedule rather than on need thereby requiring more time and energy. This is still better than a reactive maintenance approach and, in some cases, preventative maintenance is the right approach, particularly with known wear cycles.

What is Predictive maintenance

Predictive maintenance is when people or systems review data from an instrumented asset. They can then use this data to predict future breakdowns based on known models of the current condition in combination with past data points and establish the trajectory. If an asset’s condition declines rapidly, and it is being monitored closely, the maintenance team of a need to perform an activity.

Predictive maintenance with Industrial IoT (Internet of Things) enables near real-time monitoring of the machine-health at a fraction of the cost of traditional full on-line monitoring systems. It consists of sensors which communicate wirelessly and software that can analyse the data streams that are sent by the sensors. This data helps in the condition monitoring of the in-service machines and notifies the professionals upon identifying any anomalies or fault conditions. The data is collected automatically by the sensors which avoids the need for humans to routinely collect data, thereby optimizing the time spent on maintenance work. It involves predicting the failure or a malfunction of equipment, considering all the possible causes and ranking them into importance. So, it is a relatively cost-effective practice that does not require regular shutdowns to carry out maintenance as inspections and maintenance is performed only when necessary; thereby requiring less time and energy.

Predictive maintenance is meant to minimize the downtime and improve the efficiency of maintenance teams by having them focus on assets that need intervention. Many industrial plants experience maintenance issues because of various reasons, and issues are often due to lack of a comprehensive strategy for maintaining and optimizing machines. Due to the increased importance of information technology, predictive maintenance is becoming a necessity in every industry to ensure your operations are staying competitive. It is widely used among a wide variety of industries including cement, chemicals, logistics, oil & gas, power generation, mining, mining and construction among others.

Difference between preventive and predictive maintenance

Preventive Maintanence Predictive Maintanence
Can start at any time Needs data first
Time/Schedule-based Prediction-based
Planned beforehand Planned as-you-go
Needs spare part inventory Buy the spares you need
Sometimes maintenance may be performed on the machines that may not need it Unnecessary maintenance is not performed

While preventive maintenance is still a useful approach for some asset classes and processes, predictive maintenance is better at predicting the onset of failures and gives greater insight on a regular basis. When it comes to determining what maintenance approach to use, the decision has to be based on your specific scenario and the advantages of either preventive or predictive maintenance.