Mistakes To Avoid When Greasing a Bearing
Machinists and maintenance technicians know the importance of greasing bearings – it is key to maintaining an efficient machine.
When these important parts are not properly lubricated, the results can be costly and time-consuming. To help ensure smooth operation for your machinery, here's a couple tips.
1) You Don't Need to Add Bearing Maintenance to Scheduled Machine Maintenance
Basing your lubrication replenishment on a weekly or monthly schedule seems like the appropriate thing to do, but this does more harm than good. Instead, base your greasing schedule on variables. For instance, two separate motors from the same box may be in different situations. One is used in a cold climate, while the other exists in a warm climate. Or maybe, one is used in a high-speed application, while the other uses low with frequent starts and stops.
Before each scheduled maintenance, perform a basic inspection. Does the bearing perform as necessary? If so, it may not need to be lubricated. After all, the grease on bearings simply reduces friction; adding grease when it is not needed can cause catastrophic results.
2) Using the Incorrect Amount or Wrong Type of Grease
Adding too much, or too little grease can also create a significant issue. Over-greasing builds pressure causing the bearings to run hot. It can also cause the seal to fail, allowing dirt and moisture inside the elements, leading to corrosion. Ironically, too little grease may have the same life-shortening effect, allowing for the opportunity for increased heat due to the friction of moving parts.
There are also many different types of grease on the market, and each type is designed for a specific application. Using the wrong type of grease can lead to premature bearing wear or failure and costly repairs.
So how do you avoid this mistake? Using an ultrasound measuring tool can be very beneficial. Monitoring the bearing and measuring the drop-in friction as the grease fills the cavity. Be conscious of the decibel level; as it stabilizes to normal baselines, carefully slow the addition of lubricant. If the decibel level increases- stop. Using a product such as a grease gun or syringe can also give you the correct amount and placement for easy application if you don't have a ultrasonic measuring tool at your disposal.
3) Greasing Without a Measurement Device
Sometimes a moment arises where you need to grease your bearing and you do not have a measurement device, grease syringe, or the specifications for the right amount of lubrication. While not advised if you can help it, you can still follow a general rule of thumb to get your bearings back on track. When running your machine at less than 50% the speed rating of the bearing (such as Nachi's TAB or NSK's TAC bearing series), you can fill up to a half to two-thirds the capacity of free space in the bearing. However, when you are running your machine at 50% speed or more the speed rating of the bearing, you should only fill the bearing up to one-third or half the capacity of the free space within the bearing.
Using these tips will help you predict failures, control energy costs, and improve overall reliability so that your machine won’t experience any down time. Investing in the proper inspection equipment, such as an ultrasound measurement tool or a SDT can accurately filter and measure trends, as well as sound the alarms if your bearing is not running optimally. Following these tips will help keep your machinery's bearings running smoothly and efficiently.
*Don’t forget to perform regular inspections!*
