Grease is vital for maintaining heavy machinery. Ensuring you use the right grease, in the right amount and at the right time is essential to reducing your maintenance costs and increasing overall performance and productivity. Being such a crucial aspect for the maintenance of heavy machinery, let’s explore what grease is, why to use it and why grease is important.
What is grease?
Grease is a thick oily substance that is commonly used as a lubricant for heavy machinery. It can be likened to a sponge full of synthetic or petroleum-derived oil, with the sponge being the base or thickener that holds it in place. There are three components that make up a lubricating grease; the base oil, the thickener, and the additives.
- The base oil makes up 80 – 95% of the grease with mineral oil being the most commonly used. Mineral oil provides the best performance for the majority of industrial applications. Where temperatures are extreme, be that high or low, synthetic base oil provides better stability.
- The thickener makes up 5 – 20% of the grease and produces the semifluid to solid consistency of grease that we see. The main type of thickener used in grease is metallic soap which includes lithium, clay, sodium, aluminium, polyurea and calcium.
- Complex greases are made up of metallic soap, a complexing agent such as lithium soap and a low-molecular weight organic acid. Complex greases are growing in popularity due to their high dropping points and efficient load-carrying abilities.
- Nonsoap thickeners such as bentonite and silica aerogel are also gaining in popularity due to their ability to withstand high-temperature environments. However, this comes with the misconception, and warning, that despite withstanding extreme temperatures, it does not mean this type of grease will always be able to withstand temperature extremes as the base oil may not be compatible and oxidize quickly. This results in the machinery requiring to be frequently regreased.
- Additives make up a small component of grease, around 0 – 10%. Additives enhance existing desirable properties, suppress existing undesirable properties, and bestows grease with new properties. Additives such as molybdenum disulfide or graphite can reduce friction and wear without adverse chemical reactions, such as rust, to the machinery’s metal surfaces during slow speeds and heavy loading.
Why use grease?
Proper application of grease is crucial for machinery protection. The purpose of grease is to maintain contact and lubricate moving surfaces without being squeezed out under pressure or leaking under the force of gravity.
Because of its thicker consistency, grease acts as a sealant that keeps deteriorated seals effective, reduces lubrication leakage and keeps corrosive contaminants and foreign materials out. Due to its rigid quality, grease is easier to contain than oil lubricants thus saving the site from requiring expensive oil retention equipment. Where solid lubricants will settle out of oils, grease is able to hold them in suspension thus making grease the better choice in high temperature and extreme high-pressure environments.
Grease and oil have different properties and are not interchangeable. Grease is used when it is impractical or inconvenient to use oil. Generally, grease is used in situations such as:
- For machinery that is operating under extreme conditions such as shock loads or slow speed under heavy load and high pressures and temperatures.
- When machinery that runs intermittently or has been in storage for a long period of time as oil drains away when a machine has stopped but grease does not. Grease can immediately form a lubricating film thus making it effective for this situation.
- When parts are already worn as grease maintains thicker film thus can protect and extend the life of worn components that have been enlarged by wear. This is generally due to the parts being previously lubricated with oil.
- For machinery that is not easily accessible for frequent lubrication. High quality greases can lubricate components that are relatively inaccessible or isolated for long periods of time without the need to top up with grease frequently. The inaccessible components can be reached with greasing equipment such as a grease gun.
- Greasing assists with noise reduction which is important for some sites.
- For an overall reduction of the need to lubricate frequently when compared to oil lubrication.
- For overall ease of application and longer life convenience.
Why is grease important?
Under greased components create friction. This is the resistance two objects experience when moving against one another but is prevented from sliding or rolling and resulting in component wear and machine damage. To the naked eye, machine components appear to have smooth surfaces, however, on an atomic level, they are in fact rough. This means the component surfaces are dragging against each other, wasting energy and over time, wearing down the parts. When parts are greased correctly, the lubrication controls the friction and wear by applying a friction-reducing film between the moving surfaces. Grease does this by changing its consistency between the parts and cushioning and smoothing the rough surfaces of the components. Overgreasing is equally as problematic. Over greasing can cause high operating temperatures, energy loss, seal damage and premature failure. It can even push the applied grease out of the bearing leaving it with little or no lubrication at all. The issues listed here are just a few among the many things that can go wrong when grease is applied incorrectly.
As discussed, greasing correctly has many benefits, no disadvantages and is vital for maintaining machinery protection. Over 35% of all bearing failures are due to improper lubrication.
The GreaseBoss system is leading the digital transformation of greasing. Retrofittable to your existing grease gun and combined with QuickFit tags that digitalise each individual nipple on every machine, GreaseBoss utilises smart technology to its fullest. With a simple user interface and an integrated grease meter, GreaseBoss uploads the data to the secure GreaseCloud where you can view your grease analytics, per nipple, per machine, per grease run. This innovative system ensures you are using the right grease, in the right amount, at the right time so you can lubricate with confidence.