High-precision bearings are used in many applications that range from surgical robots requiring smooth movement and low deviation to the high speeds of turbines allowing for stable rotation and reduced vibration.
Here’s what to consider when selecting a bearing for your high-precision application, assuming typical bearing considerations have been met.
Precision Level
In the U.S., the most commonly used standard for bearing precision is the Annular Bearing Engineering Committee (ABEC) scale. Consider reading “ABEC Scale for Finding Ball Bearing Precision” for a quick review on choosing the correct bearing precision and equivalent standard scales from around the world.
To summarize, the higher the number in the ABEC scale, the tighter the precision. While technically any bearing with an ABEC rating is considered “precise,” this post will focus on what is considered “high precision” in ABEC 5, 7, and 9.
When the operation you are trying to accomplish occurs a distance away from the bearing, a tighter tolerance can help with any runout that could be experienced with looser bearings.
Operating Speed
If your application requires low operating speed, such as robotic arms, ABEC 5 bearings can offer a great combination of precision and durability. While it’s possible that a higher rating could create smoother operation, it might be overkill for what your design needs.
For applications that demand higher operating speeds and smooth rotation, such as high-speed machinery or aircraft gyroscopes, ABEC 7 and 9 bearings are the best choice due to their precision and efficiency. They’re capable of handling high speeds without excessive friction or heat, which protects it from expansion and premature failure.
Loading Type
Due to the tight tolerances held by higher ratings, shock loads can have a major impact on the life of your bearing. To stop issues like lubricant breakdown and misalignment from occurring, choosing a lower-rated bearing could allow for some more wiggle room.
When your loading is consistent and combined with high speed, the slightest imperfection could cause your operation to fail. Moving to higher-rated bearings will close the gap and reduce irregular motion and noise that would otherwise occur with lower-tolerance bearings.
Performance vs. Cost
A higher-rated bearing is not strictly a better option for your application. With a higher rating comes a higher cost in manufacturing that you might not need or definitely don’t want. It’s always worth asking if you can accomplish what you need at a reasonable price.
Inversely, consider the need for routine maintenance and if unexpected downtime could cost more than the initial investment of a smoother bearing.
Having the comfort of mind to know a purchased part will have the tight tolerances required to avoid issues like tolerance stack-up or bearing seizing could save a lot of money and headache for your builders and testers.
When selecting a bearing for your high-precision application, remember to consider the level of precision needed, what your operation speed will be, and what kind of loads your system will be experiencing. ABEC 5 bearings can meet the requirements of most applications, while ABEC 7 and 9 bearings are better options for top-tier precision.
What highly precise examples have you seen in your experience? For an in-depth review on bearing selection, start off with “How to Select the Right Bearing Part 1.”
Take a look at the wide range of precision bearings, both ball and roller, from brands like NTN, FAG Schaeffler, and NSK offered through MISUMI.
