The Difference Between Preventive and Predictive Maintenance
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Posted by Michael S. on April 13, 2016 in Manufacturer Focus

Look around your manufacturing facility; you have a lot of machinery. A key to keeping your machinery running well is your maintenance strategy. There are two main types of maintenance strategies—preventive maintenance and predictive maintenance. These two are often intertwined and the terminology is not used correctly.

 

Preventive maintenance (PM) has been around in some form since the first piece of mechanical machinery was put to use. PM is focused on maintaining the machine as close as possible to the original, or optimal, condition. It is generally based on a set schedule, which could be time, distance, or use. For example, your car owner manual requires you to perform maintenance at 10,000 miles, which could include oil change, air filter replacement, belt check, and lube job. This 10K PM is based on one indicator, miles driven. This does not consider things like temperature, time it took you to drive the 10K miles, or load on the vehicle. PMs are time consuming and can be costly.

 

It is a good idea to check, inspect, repair, and replace things at set intervals.

 

However, doing maintenance based on time or distance indicators doesn’t consider actual conditions such as temperature, operating at higher rpms, stop-and-go situations, and any potential downtime. When using the PM method for maintaining equipment, you are following original equipment manufacturers (OEM) guidelines, which were developed by manufacturers for average conditions and situations.

 

Predictive maintenance (PdM) is based on actual operating conditions. It came about because equipment still failed or didn’t function effectively or efficiently after PMs were performed. PdM requires sensors to be added, such as heat sensors on bearings or oil condition monitoring. Sensors help monitor individual components and the stress that components are working under. If you drive your car in a 140-degree desert with a loaded trailer, the sensors will track the extra stress on components like transmission, oil, and suspension and then record them to a monitor unit. The monitor unit will track and calculate the maintenance interval and flag you through an indicator light on the dash. It notifies you what specific maintenance needs to be performed.

 

You can have the same sensor technology in all your equipment, giving you real-time maintenance information. PdM takes advantage of additional, portable monitoring systems, like ultrasonic, infrared, digital heat guns, and vibration analyst tools. These additional tools allow you to check machine spindles or bearings for potential issues before you shut down. This allows you time to order replacement parts, preventing catastrophic and costly unscheduled downtime.

 

With the latest sensor technology and IIoT (Industrial Internet of Things), you can connect output sensors and tools to communicate with your enterprise resource planning (ERP) system. This gives your production schedulers, maintenance managers, inventory planners, manufacturing staff, and purchasing people real-time information so they can plan and schedule for needed maintenance.

 

PM is the first step in improving equipment reliability. The next step is PdM, allowing you to prevent unplanned failure and only perform maintenance that is needed. PdM makes your operation more reliable, accurate, and cost effective. It is definitely something you should look into implementing in your facility to keep your machines running at their optimal condition. 

Michael S. is our Manufacturing guru
I have over 30 years experience in a broad range of manufacturing areas. Starting with an apprenticeship in Germany I’ve worked my way through a verity of positions within the manufacturing field. I got my start as a Tool and Die maker. I next became a supervisor of a class A tool room, then manager of a machining department. I was exposed to lean manufacturing in the mid 90s and adapted the lean philosophy. Loving and teaching the lean approach, I moved on to become a Continuous Improvement manager which led to a job as a manufacturing manager. I joined Acuity in 2015 as their manufacturing expert. I hope to evolve how manufacturers deal with, and think about insurance companies, as well as be a resource to my fellow employees – enabling them to better understand the unique needs of manufacturers.


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