Bearing grease: How to application
Bearing grease: application methods
Relubricating the bearing grease is of great importance to ensure the longevity of your ball- and roller bearings. Bearing grease provides a smooth process with as little friction as possible. Bearing grease is also necessary to avoid direct contact between the rolling elements and their treads.
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Regular grease lubrication
Most applications require that you relubricate or replenish your bearing grease. Though the bearing grease stays put and barely leaks, old grease can dry out eventually and therefore be less effective. This is ecause the base oil spreads out over the moving parts of the bearing and the thickener vaporises through the heat.
How you replenish or renew your bearing grease depends on the application it is used for. Occasionally a machine has a built-in ‘replenishing mechanism’ which makes lubrication quick and easy.
Assortment bearing grease
Discover the assortment of bearing grease and find the right product for your application.
View the assortment
2. Tools and resources for your application
If you wish to manually apply your bearing grease, there are certain tools available. These tools ensure that you work cleanly and can distribute the bearing grease precisely and evenly.
These are widely-used tools to distribute bearing grease manually:
- Grease gunAdvantage: a grease gun prevents contamination in a machine. The gun makes it easy to accurately apply the grease onto the bearings. Uses: agriculture, industry, automotive industry and in construction.
- Volt grease gunAdvantage: a volt grease gun prevents you from using too much or too little bearing grease. This gun comes with a grease meter, so you can measure your doses accurately. Uses: agricultural vehicles, bearings and (high-speed) machines in an industrial or production setting.
- Bearing packerAdvantage: a bearing packer fills open bearings completely with bearing grease without risk of contamination. Uses: e.g. tapered roller bearings.
- Grease filler pumpAdvantage: you can quickly and hygienically clean your grease gun or bearing packer with a grease filler pump. Uses: in combination with a grease gun or bearing packer.
- Grease pumpAdvantage: the grease pump should be used if you must use large quantities of grease. Uses: large bearing casings, applications with several lubricating points and containers of central lubrication systems.
- Grease meterAdvantage: Instantly check how much grease needs to be applied with a grease meter. You will not have to calculate your grease use and avoids either an excess or lack of grease used. Uses: use in combination with a grease gun..
Together with these tools, there are also accessories that can make applying or replenishing grease easier, cleaner and more precise. Accessories include connecting pieces, couplings, nozzles, head caps and grease-resistant disposable gloves.
3. Application methods for bearing grease
There are two methods available for lubricating or replenishing bearing grease. These are then divided by different methods.
Manually
- With a (volt) grease gun
- With a grease pump (large volumes)
- With a bearing packer (open bearings)
Automatically
- With an automatic single-point lubrication unit.
- With an automatic multi-point lubrication unit
Perma is an A-brand with ready-to-use automatic systems for lubrication.
How much bearing grease do you use?
The amount of grease you should use is indicated through a percentage. The percentage indicates the grease volume in relation to the internal space of the bearing. If the bearing needs to be filled up entirely, the percentage will be 100 percent. The manufacturer of your bearing usually designates the standard percentage for your bearings. Usually this is between 20 and 40 percent.
Establish the quantity
The percentage is largely determined through the rotational speed of the bearing. We recommend a 50% to 65% bearing grease when the rotational speed is less than 50% (of the maximum speed). For a rotational speed that is higher than 50 per cent, the recommendation is a bearing grease percentage of 30% to 50%.
The percentage is also dependent on these factors:
- The design of the housing
- The available space
- The specifications of the bearing grease
- The ambient temperature
Where to apply the bearing grease
Most bearings come with a handy opening for relubrication. This opening also ensures that the grease reaches the core of the bearing. If you relubricate the bearing here the old grease will be pushed outside, and the new grease will not staple on top of the old
If it is not possible to relubricate at the core, then you should relubricate on one side of the bearing. Then the old grease has a chance to pushed out from the other end. Some machines typically come with either an opening or a way for the old bearing grease to find its way out through sealing lips.
For applications that are being used in industries with abrasive particles, the bearing grease also serves as a filter to collect these particles. By consistently relubricating these bearings you also purge them of the contaminated grease from the bearing housings. Please note that you must relubricate the bearings in time before the grease has become completely contaminated.
Assortment bearing lubrication systems
Discover the assortment of lubrication systens and find the right product for your application.
View the assortment
4. What method works best for you?
Usually, the manual method is chosen in applying bearing lubrication. When there several lubricating points or when lubricating is complex, one typically chooses the automatic method. It is best to choose a specific method when it comes to certain applications or industries.
| Application / Industry | Lubrication method |
|---|---|
| Machines and mechanisms with closed bearings | Manual lubrication with a (volt) grease gun |
| Machines and mechanisms with open bearings | Manual lubrication with a bearing packer |
| Machines and mechanisms with a large number of bearings | Manual lubrication with a grease pump |
| Torque sensitive applications where the grease must remain in place | Manual lubrication with grease plating |
| Minuscule bearings or bearings from instruments | Manual lubrication in a clean environment |
| Machines and mechanisms with difficult to reach lubricating points (e.g.: pumps, ventilators, blowers, transport tires and chains) | Automatic lubrication |
| Factories and other industries with a lot of lubricating points (which could have different lubrication frequencies and needs) | Automatic lubrication |
| Machines and mechanisms where lubricating points may be behind safety cages | Automatic lubrication |
| Machines and mechanisms where lubricating points are at a high altitude | Automatic lubrication |
5. Manual vs. automatic lubrication
Manual lubrication knows a few drawbacks. First, most applications must be brought to a halt which requires employees. When the lubrication isn’t done properly, either by smearing too much or too little, this may lead to problems in the future.
Too much grease can contaminate the product whereas too little grease increases the chance of abrasion, premature repairs and high repair costs. Automatic smearing minimises the grease use, waste, the threat of contamination, human error and defects. It also optimises the bearing performance, grease amounts- and frequency, the accuracy, safety and use per time unit.
That said, manual lubrication is a good choice for many applications. Please keep in mind that you must work accurately and sterilely for which you can use tools and accessories like a grease gun and disposable gloves. There are also lubrication management tools available that stipulate the right amount of lubrication necessary.
Crucial: using bearing grease on time
Using bearing grease on time is crucial in ensuring an optimal lifespan of your bearings because it prevents the chance of contamination and defects. ‘Timely’ lubrication can be tricky to predict. You need to account for these variables:
- The bearing temperature when the machine is in use
- The number of daily hours that a machine is in use
- The bearing size
- The rotational speed of the bearing
Sometimes one machine will have bearings with different intervals, some will require daily lubrication whilst others only require a monthly lubrication check. In that case it’s wise to also do a thorough check of your machine once a year: wash off the old bearing grease and relubricate the machine from scratch.
One tip: send used bearing grease to a lab for further analysis to establish which bearing grease is right for your application.
Advantages of relubricating in time (and the risks if not)
Bearing grease is necessary to prevent bearing defects and is vital for the lifespan and functioning of your bearings.
| Advantages of timely lubrication | Risks of not properly lubricating |
|---|---|
| Higher productivity of the machine | Higher energy consumption of the machine |
| Higher operating reliability (through a higher reliability of the machine) | Machine downtime (through friction) |
| Durable machines | Abrasion, noise pollution, heat development (through friction) |
| Better operational capacity | Product contamination |
| Bigger maintenance intervals | Higher company-, maintenance- and reparation costs |
| Higher level of safety | Bigger chance of work accidents |
6. Common mistakes and guidelines
During lubrication, many of the mistakes are usually repeated offences. Please make sure that you prevent the two most common mistakes by following the guidelines below.
Mistake 1: lubrication is only based on time
Lubricating a machine once or twice per month is consistent. But if the machine hasn’t been making enough hours to require new bearing grease, this means that there is too much grease in the bearing. If a machine clocks too many hours or if the grease evaporates due to a high temperature, it will create friction before (re)lubrication. This is exactly what a bearing grease should prevent from happening.
Guideline: Monitor, measure and map the friction with ultrasonic waves.. You will know exactly when you need to relubricate your bearing grease.
Mistake 2: too much or too little bearing grease
Using the right amount of bearing grease is crucial for the efficiency of the bearing and minimising the amount of friction. If you use too much grease, this will cause an excess amount of pressure in the bearing that will press the rolling elements towards the outer ring. In short: the bearing has to work much harder, causing a temperature increase, which then decreases the effectiveness of the grease.
When the heat increases, the base oil separates from the thickening agent. Too little grease has an adversary effect on the longevity of the bearing.
Guideline: Check the friction level with ultrasonic waves when you apply the grease. Carefully apply the grease and measure before you apply more. Stop applying grease as soon as you notice an increase in the decibel level.
Requirements of measuring instruments for the friction level
- The instrument provides measuring feedback
- The instrument has a digital decibel scale
- Preferably, the instrument has multiple condition indicators in order to measure which bearings need bearing grease and which bearings need to be replaced
Practical lubrication management tools
For the optimal lubrication of all bearings in your machines or industry, you can use lubrication management tools. Think of software like the LubeSelect for SKF-greases (software for lubricant selection and when to lubricate), the SKF lubrication planner (tool for lubrication planning) and the SKF Dialset (provides you with information for re-lubrication intervals and quantity calculations).
