Maintworld 4/2019

PARTNER ARTICLE
» Lubrication Excellence is something
we all strive for, but few organizations
can prepare a winning strategy the
whole team can execute, states Field
Support Manager Haris Trobradovič.
» LUBExpert Generation 3 interweaves
elements of discipline and control
that holds all stakeholders accountable.
With LUBExpert, you really feel
the pulse of your machine.
Existing LUBExpert users will receive
the latest updates and enhancements
free of charge. Watch your email for release
and instructions notes or contact
your local distributor to Hear More.
About SDT
SDT provides ultrasound solutions that
help our customers gain a better understanding
about the health of their factory.
We help them predict failures, control
energy costs, and improve product
quality while contributing to the overall
reliability of their assets.
LUBExpert is a keystone element of
our products and solutions portfolio. To
Hear More please contact SDT Ultrasound
Solutions hearmore@sdtultrasound.com
Why Lubricate?
It seems a simple question, yet when
asked, the answers are not always similar,
or simple.
Some say, “to fight friction” and that
is true. We do add grease to an asset’s
moving parts to reduce friction. But
there’s more to it than that.
Some say, “to reduce heat” and that is
also true. The right amount of lubricant
does help keep moving parts from getting
too hot. But some lube techs, thinking
more is better, take it to the extreme.
They add more grease -- thinking they
are doing good -- and instead choke the
machine’s ability to disperse heat.
The real reason to lubricate assets is to
form separation between surfaces. This
logic applies to not only motor bearings.
The pistons in an engine, chains on a chain
drive, gears in a reducer, even linear bearings
that do not rotate, but slide back and
forth. The primary purpose to lubricate
physical assets is to keep moving surfaces
from coming into contact with each other.
Because when they do, failure modes are
initiated, and lifecycle is shortened.
Friction is a force which opposes
movement between surfaces. Friction
increases wear between surfaces, increases
system temperature, and dramatically
increases power consumption.
The right amount, and type of lubricant
creates a thin film between two surfaces.
For as long as that film is maintained, it
protects the asset from wear and heat
while allowing it to produce in an energy
efficient way.
Some lubricants offer the additional
benefit of controlling corrosion. They
contain additives which prevent rust
from acid and water attacks.
Grease must be kept free of contaminants,
but the very nature of the thickener
allows it to pick up dust and grit.
Proper storage is therefore crucial, and
clean grease applied properly can actually
shield machines from the ingress of
contaminants.
The science of lubrication continues
to evolve for over 4000 years. But the
principles remain the same; to maintain
separation of two or more surfaces, thus
prolonging the reliability of the entire
asset.
What is Grease?
Tremendous science goes into engineering
the many grease formulations that
keep physical assets working their best.
The sheer number of grease types
available is as varied as the applications
where they are used. Yet their composition
remains a simple mixture of base
oil, thickener, and in most cases some
additives.
The Base Oil is the key ingredient of
grease. Its job is to form the thin, hydrodynamic
film that separates metal
components from one another. When
functional separation between elements
is maintained, the bearing has what we
term a functional grease mechanism.
Base oil is the key ingredient when
matching grease types to specific applications.
Thickeners are the matrix of the
grease. Base oil cannot resist gravity
on its own. It relies on the thickener to
hold it in place. The thickener makes
grease effective regardless of a machine’s
orientation. For instance, in a vertically
oriented shaft, the base oil would seep
away from the bearing making a sustainable,
functional grease mechanism
improbably. In addition to keeping base
oil where it’s needed, thickener has the
added benefit of shielding the base oil
from particle contaminants.
Additives are a double-edged sword.
On the positive side, they enhance the
lubricating properties of the base oil. Additives
increase the lubricity of the base
oil making grease even more slippery.
They help fight oxidation, corrosion, and
extreme pressure conditions.
On the negative side, they are a consumable.
They deteriorate over time, so
their effectiveness is not linear for the
life of the grease. Additives can also have
adverse effects on the thickener.
Additives add an unknown function
to the mad science of calculating timebased
grease replenishment intervals.
Most departments working on calendarbased
lubrication don’t factor additives
into the equation, further compounding
their errors.
While considerable science goes into
formulating grease types, what the lube
technician needs to know is that the
grease he or she injects into the bearing
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