Lubricants like oils, greases and fluids are made by leading manufacturers such as Mobil, Q8 and Morris, and they are sold through suppliers to enterprises so they can keep their equipment operating at optimum.
The three key lubrication types are full-film, boundary and mixed. In the following sections, we’ll take a closer look at the different types of lubrication currently available, which are each suited to different mechanical processes, operations and environmental pressures.
Full-film lubrication – hydrodynamic and elastohydrodynamic
Full-film lubrication is a type of lubrication that can be further separated into two different subsets, which are known as elastohydrodynamic and hydrodynamic. Full-film lubrication seals individual components, protecting them from not only friction, but unwanted contaminants; however, this is no mean feat. Even parts that appear to be smooth have microscopic irregularities that form peaks and troughs on surfaces. In order for a full-film lubrication to be effective and completely seal components, it must always be thicker than the height of any protruding irregularities.
Hydrodynamic lubrication is defined by the process of two adjacent surfaces that are moving in a sliding motion relative to one another, while being entirely separated by a lubricant film to stop any friction from occurring, which would cause unwanted wear to parts.
Elastohydrodynamic lubrication is described as process of two adjacent surfaces relative to one another that are moving with a rolling motion while being separated by the film of lubrication fluid. The lubricant film present in elastohydrodynamic lubricating conditions is considerably thinner than the film seen in hydrodynamic lubrication. The pressure put on the film is also far greater. The term elastohydrodynamic is given to the process because the lubrication film is able to elastically alter its form to adapt to the rolling surface to effectively lubricate it, so it remains protected.
Boundary and mixed lubrication
Boundary lubrication is a type of lubrication associated with machinery that involves a lot of starting and stopping, and usually where shock-loading is present. There are some lubricants available that are enhanced with a specially designed additive package, giving the oil or grease improved operational abilities under such conditions, like anti-wear (AW) and extreme pressure (EP).
Machinery that operates at intense speeds can render full-film lubrication untenable, so boundary lubrication infused with EP and AW additives can assist by offering protection to parts. These cleverly formulated additives adhere to the metal surfaces of components and form a protective layer that takes the brunt of any wear and tear. Boundary lubrication is defined by a process when two adjacent surfaces are making contact and all that protects them is this additive layer.
Finally, mixed lubrication combines elements of hydrodynamic and boundary lubrication. While most of the metal surfaces are protected by a lubrication film, some raised irregularities in parts will meet but be mitigated by the AW and EP additives.
While all three types of lubrication are entirely different, they all depend on a base lubricant and a well-designed additive package that provides enhanced anti-wear properties.
