The Path to
When Bearings Fail Prematurely
The Challenge For
Traditional Time-Based Lubrication
With The Right Tools
Identifying The Source Of A Sound
Ultrasound Assisted Lubrication
Any Lubrication Method Is Better Than None
The Best Case Scenario
UE Systems Ultrasound Instruments
FORTUNATELY, THERE ARE EASY SOLUTIONS FOR POOR LUBRICATION PRACTICES.
WHEN BEARINGS FAIL PREMATURELY,
POOR LUBRICATION PRACTICES ARE OFTEN THE CAUSE.
In fact, over 80 percent of premature bearing failures
can be traced to a problem with lubrication.
The proper amount of bearing grease dampens the stress caused
by the rolling element bearings, the housing and the shaft.
That damage can go unnoticed until the bearing fails completely,
disrupting workflow, creating downtime and causing financial loss.
Too little lubrication
creates heat and adds
stress on the bearings.
Too much lubrication,
believe it or not, also
increases friction and
has the same effect.
Using the correct
lubrication type for the
Storing lubricant in a
way that keeps it cool,
dry and clean.
Filtering lubricant as
necessary and in the
maintenance tools like
ultrasound to assist in
the timing and amount of
THE BEST LUBRICATION METHOD CONTAINS EACH OF
THESE FACETS WITHOUT LEAVING ANYTHING OUT.
THE CHALLENGE FOR
IS TO DEVELOP A BEARING LUBRICATION PROCESS THAT ENSURES
THE CORRECT AMOUNT OF GREASE EVERY TIME.
Simply eyeballing the right amount – even for seasoned maintenance veterans – isn’t the best strategy.
Instead, these professionals should leverage a reliability centered
lubrication process that revolves around several best practices:
WHAT IF THE BEARING ALREADY HAS ENOUGH GREASE?
WHAT IF THE SCHEDULED LUBRICATION IS TOO FREQUENT OR NOT FREQUENT ENOUGH?
WHAT IF THE AMOUNT OF GREASE APPLIED IS TOO MUCH OR TOO LITTLE?
WHAT IF THE BEARING HAS ISSUES BEYOND LUBRICATION?
MANY FACILITY MAINTENANCE TEAMS RELY ON
TIME-BASED LUBRICATION –
A TRADITIONAL METHOD THAT ESTABLISHES
INTERVALS FOR LUBRICATION AND
A SET AMOUNT OF GREASE.
This technique may seem like a solid approach, but there are a few gaps
that could result in early bearing failure even if the schedule is followed
to perfection. Consider:
OF THESE, THE CHIEF CONCERN FOR THE
TIME-BASED APPROACH IS OVER-LUBRICATION.
Often, the bearing will end up with far more lubricant
than necessary, which hastens the onset of failure mode.
IS A BETTER STRATEGY.
To help establish a condition-based lubrication protocol, maintenance professionals
use the I-P-F model to analyze a piece of equipment’s life, from installation to point-of-failure.
Rather than establishing a rigid structure for lubrication based on time intervals,
maintenance teams can use a combination of equipment run time,
historical data and condition monitoring tools to detect mechanical failures.
THIS IS FUNDAMENTALLY A DIFFERENT WAY TO LUBRICATE –
using asset health and alarm indicators as the determining factor
for when to apply lubrication and in what portion.
WITH THAT SAID,
MONITORING WORKS BEST
IF MAINTENANCE PROFESSIONALS HAVE
THE RIGHT TOOLS AT THEIR DISPOSAL.
In fact, ultrasound can go even further – the technology detects
slight changes in amplitude or decibel levels due to increased
friction, either from too much or too little lubrication.
IN MANY CASES, ULTRASOUND CAN REDUCE GREASE CONSUMPTION BY 30 PERCENT.
To that end, ultrasound is an excellent way to find early stage bearing failures.
By incorporating ultrasound into best lubrication practices, the results can include:
Fewer lubrication-based failures.
More accurate and efficient lubricant usage.
Longer motor and bearing life.
Lower rebuild or repurchasing costs.
The discovery of otherwise undetectable problems.
Better overall reliability.
Generally, there are three sources of ultrasound:
WITH THE RIGHT TRAINING AND TOOLS OF THE
HIGHEST QUALITY, ULTRASOUND OPERATORS CAN
IDENTIFY THE SOURCE OF A SOUND
AND LEARN TO IDENTIFY THE TYPE OF ISSUE
THAT MAY BE CAUSING IT.
These are defects that create sound, but at a frequency outside
what the human ear can perceive. Human hearing ends at about
20 kHz and that’s right where ultrasound begins.
THESE SOUNDS ARE LOW-ENERGY, WHICH MAKES IT EASY
TO TRACE THE EXACT SOURCE OF THE SOUND.
In this way, ultrasound can help pinpoint any number of
early failure defects – not only those related to lubrication.
For lubrication specifically, though, ultrasound is ideal.
Turbulence Ionization Friction and impacts
< 20 kHz > 20 kHz
That gives them the necessary data points to determine exactly how much grease is
required at any given time. These professionals will know what they need to do by simply
listening and reading the feedback:
ULTRASOUND ASSISTED LUBRICATION
IS A PROCESS BY WHICH MAINTENANCE PROFESSIONALS
MONITOR AND TREND DECIBEL LEVELS
IN A BEARING WHILE GREASING.
8dB above baseline
indicates a lack of
16dB above baseline
to the bearing – a
failure mode beyond
baseline means the
asset is critical –
it is close to failure.
As the operator adds grease, he or she will notice a gradual drop in decibels.
ONCE THE LEVEL FALLS BACK TO THE BASELINE,
THE BEARING IS SUFFICIENTLY LUBRICATED.
If the decibels increase, that means there is already enough lubricant.Even if ultrasound finds
no change in decibels after adding grease, that is still actionable information. The inspector
can follow up with a spectrum analysis of the recorded ultrasound sound file, vibration
analysis or some other technique to determine why there was no change in the decibel level.
8dB 16dB 35dB
At the very least, maintenance professionals should:
ANY LUBRICATION METHOD
IS BETTER THAN NONE WHATSOEVER,
BUT SOME TECHNIQUES ARE BETTER THAN OTHERS.
To take it a step further, these individuals should also:
Ensure the correct
grease is being used.
Lubricate to the
Calculate the amount
of grease based on
bearing type and size.
time and operating
Implement a basic
ultrasound device to
listen to the bearing
Track the changes
in decibel level with
Make note of any
other issues that
may be unrelated
Use an ultrasound tool with data collection functions to record the
decibel level and the sound file for future analysis and comparison.
Set baseline, high and low alarms after enough data is compiled.
Establish a follow-up inspection after lubrication to ensure the
bearing is still functioning as expected.
Create a report – a Lube Report, Alarm Report, 4 Image Report
and FFT and Time Wave Form images from a spectrum analysis
software are all good examples.
BEST CASE SCENARIO,
THE LUBRICATION METHOD WILL TAKE
INTO ACCOUNT ALL OF THE ABOVE,
WITH THIS STRATEGY, OPERATORS WILL FIND MORE PROBLEMS
AND RESOLVE THEM BEFORE THEY BECOME DEBILITATING.
There are a range of options:
UE SYSTEMS PROVIDES
CAPABLE OF ALL LUBRICATION NEEDS.
ALL BEARINGS FAIL EVENTUALLY – THAT’S A FACT OF FACILITY MAINTENANCE.
But they don’t need to fail as often as many do. Proper lubrication is key to healthy, long,
productive bearing lives and the right ultrasound tools play a major part in that process.
The Ultraprobe 201 Grease Caddy is
simple to use, cost-effective and will
let the operator know when he
or she has applied enough or
too much grease.
The Ultraprobe 401 Grease Caddy
can store data, trend decibel levels
and grease amount, store a before and
after decibel level, record the number
of grease pumps and can be used with
remote access sensors if equipment
access is restricted.
14 HAYES STREET
ELMSFORD, NY 10523