Self-lubricating bearings are a popular choice for applications where regular lubrication intervals are logistically impossible or cost prohibitive. But remember – self-lubricating bearings still require some additional lubrication and getting this wrong is one of the top causes of bearing failure.
Here are three common mistakes made when it comes to specifying and maintaining self-lubricating bearings, and how to avoid them:
Mistake one: Using grease instead of oil
Grease and oil have different lubrication properties that make them ideal for specific applications. Using them incorrectly will lead to bearing failure and unplanned downtime:
- Grease should be used in high load applications.
- Oil should be used in high-speed applications.
To avoid making this mistake, make sure you understand the temperature, speed, load, and environmental conditions that will impact the bearing during operation to determine whether oil or grease is the right lubricant. If you aren’t sure, speak to your manufacturing partner for consultative advice before placing an order.
Once the bearing is installed, always follow the manufacturer’s guidance on which lubrication is right for you.
Mistake two: Specifying dry lubricants when they are not appropriate
When specifying bearings for high-maintenance applications like heavy loads or extreme temperatures, dry lubricants are not the right option for you because you will need to replace the entire bearing every time.
These bearings offer limited corrosion protection too, which can render them inappropriate for applications where corrosion protection is important.
Dry lubricant bearings are ideally suited for environments where liquids, oils and greases should be avoided such as high- and low-temperature, or high- and low-pressure applications, which may freeze or degrade the lubricating substance.
The only way to avoid this mistake is to understand your application thoroughly before you specify the bearing and seek advice from a manufacturer that offers a vast portfolio of bearing options.
Mistake three: Specifying the wrong additives for certain shaft types
Self-lubricating bearings use additives like graphite plugs or PTFE lining to create a thin film between the shaft and the mating surface of the bearing. When specifying these products it’s critical to understand the characteristics of the shaft material and how it could affect the lubricant film being generated.
When running with a stainless-steel shaft Molybdenum Disulphide (MOS2) should be added to the oil as the stainless properties of the shaft prohibit a full oil film from being generated.
To overcome this problem, understand your shaft material at the point of specification and ask your bearing manufacturer to confirm how this will interact with the self-lubricating additives you want to use.
They will be able to either recommend a different product or suggest the use of something like Molybdenum Disulphide (MOS2) – a dry lubricant used to improve the coefficient of friction for stainless steel shafts.
Avoid mistakes with a consultative partner
With a consultative manufacturing partner in your corner, avoiding mistakes like these is easy. If you need advice from someone who can offer technical knowledge on a broad range of bearings for applications across North America, DM me to arrange a meeting.
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