What is better for your business? Predictive Maintenance Vs. Preventative Maintenance
Whatever the cause, when electricity, lights, and machinery aren’t working properly, work comes to a stand-still. The backbone of any sound maintenance program is the ability to prevent unplanned downtime and keep a productive work environment.
There are two trains of thought on how to ensure that unplanned outages don’t occur, predictive maintenance and preventive maintenance.
These two terms are often incorrectly interchanged. Preventive maintenance (also called planned maintenance or planned preventive maintenance) is driven by time, meter, or event based triggering. Predictive maintenance is determined by the condition of equipment rather average or expected life statistics.
Here are the advantages and disadvantage of both and how to determine which maintenance program is right for you.
This strategy is employed by most companies and almost all small to mid-sized companies make exclusive use of it. It consists of assets being taken offline, inspected at periodic, predetermined intervals, and repaired if necessary.
The advantage of a preventative maintenance plan is its simplicity. It is a relatively easy strategy to set up and to execute making it a common maintenance strategy for smaller businesses.
Preventative maintenance can prove quite costly in the long run as a majority of the time these inspections are a straightforward pass.
It iss recommended that serious attention be given to the efficiency of these schedules. If most inspections come with a pass, possibly schedules should be lengthened or swapped out for predictive maintenance.
Predictive maintenance (PdM ) is determined by the condition of equipment, rather than average or expected life statistics. Essentially, this methodology tries to predict the failure before it actually happens by directly monitoring the machine during normal operating condition.
The advantage of PdM (over PM) is the potential for cost savings from reduced man-hours spent on maintenance, and more insight as to the performance and potential issues arising with the machine.
Predictive maintenance is more complex than preventative maintenance. Typically, monitoring equipment is linked to a CMMS, and generates work orders based on some meter reading (PSI, vibration analysis, widgets/hour) gathered by the monitoring device. It may also be simpler than this, such as visual inspection by operators on the quality or speed at which the equipment is performing.
Two additional maintenance strategies are Run-to-failure (breakdown maintenance) and Reliability-centered maintenance (RCM). These strategies are not as widely used and are more specific in nature, being implemented only for certain equipment.
Run-to-failure (breakdown maintenance)
An acceptable strategy for equipment that is of minimal importance to operations (rarely used or duplicates the function of some other equipment) or has low cost. Equipment designated as run-to-failure are fixed in the event of a breakdown (by repair, restoration or parts replacement) until it is more feasible to simply order a replacement equipment.
Reliability-centered maintenance (RCM)
Emerging from the realization that equipment failure probability is not linear, RCM is an in-depth, highly involved process that seeks to analyze all the possible failure modes for each piece of equipment, and customize a maintenance strategy for each individual machine.
The general consensus is that RCM is too sophisticated a technique to be of much practical use. RCM is therefore reserved for an elite class of organizations that have already mastered the basics – maintenance prevention, basic inspections and predictive maintenance.
Determining which method to chose, is often based or organization size, budget, and value of an asset. It is not uncommon, to have a mixture of strategies. No matter which you choose you must have a strategy that cost effectively works for your business, so you can stay productive.