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Ron Jonkers'
thoughts about setting up a world class lubrication program
More than 50% of
mechanical failures are caused by improper lubrication. Therefore this
makes lubrication the most underestimated and ill performed act in
machine maintenance. Even nowadays there are a lot of people who think
that machines can perform without any attention from the maintenance
department, and in special from lubrication engineers. This is simply
proven by the failure figures.
A machine not
given proper attention will have a lifetime less than half of the normal
operating lifespan, will have far more unexpected breakdown time, put
out less than standard performance in terms of production per hour with
less than acceptable quality.
Upper level
management is aware of the problem, but might not know how to tackle the
problem. Maintenance departments are often stuck in some sort of
status quo, and by that I mean that they use most of their time keeping
up with the normal daily occurrences in their plants. There simply isn’t
enough time to improve on maintenance strategies. Or people find the
(lubricating) task at hand not interestingly enough.
One maintenance
group leader put it this way: ``we employ a lot of technical graduates,
but they don’t want to do the dirty work of lubrication. That’s not what
they’ve been to school for``. Because basic technical schooling in the
Netherlands is long since replaced by general basic schooling, good
technical hand craftsman are hard to found.
On the other hand,
the need for good educated basic technicians is growing since
lubrication engineering is becoming a science in itself. Every day we
learn more about lubrication, its basics, the specifics of oils and
greases, synthetics, breakdown of the oil film, changing of viscosity –
base number – acid number, contamination and so on.
To perform a world
class lubrication program takes specially educated technicians. It takes
reading a lot of study books, mechanical and chemical, even more
articles, follow on-line courses etc. These days you can even apply for
formal training and examination.
But to start a
good lubrication program doesn’t have to be a very big problem. However
the first rule is that higher level management, maintenance management
and maintenance engineers agree on the need for such a program.
If there is only one who isn’t convinced that a program will result in
improved performance, better keep your money in your pocket. You first
have to make sure that everybody will support the program and will
perform to the best of their ability in putting the program in place.
Remember that only one unmotivated engineer assigned with the
lubrication task can corrupt the program. So, convinced managers
and highly motivated lubrication engineers can do the job.
Convincing arguments could be the reduction of (general) costs,
downtime, quality rejects and energy demand, the last being the result
of extra low friction lubs inspired by the Kyoto agreements on Co2
reductions and ISO 14001.
The second rule is
the strategy of lubrication and re-lubrication. Simply
changing oil in gear drives or pumping grease in bearings doesn’t do the
trick. One should consider the state of the oil, degradation of
additives and anti oxidants, change in viscosity, the amount of wear
particles in the oil, bleeding of oil in grease, accumulation of old
soap, how much grease is to be applied and how to apply it and more. Is
the right grease or oil used, is there a better solution for this
application or are we going to put the same grease in all the bearings,
big or small, high or low rpm, under or over burdened? Also consider
type of industry (HACCP, food contamination) and environment, inside or
outside, heat, freezing cold, dust, vibrations, misalignment and
production stop intervals to name a few.
The third rule is
consideration of the tools to be used. Are you going to use fixed
continuous re-lubrication systems, oil filtration, hand pumps, oil
analysis and ultrasound technology. If a handgun is used, beware
of dirty grease ports. Can you guarantee uncontaminated refills of fixed
continuous re-lubrication systems or oil reservoirs? (think of dust,
flying product particles, leaks)
A final
consideration is: Is enough grease or oil going into the bearing, or
not? For instance, when relubricating electric motor bearings, or
any other bearing for that matter, how do you know when to stop pumping
or when to stop the automatic cycle? For a long time now
lubrication engineers used supplier information on how much
re-lubrication at what intervals should be applied.
Ultrasound
technology on the other hand provides a certain way of knowing
the answers to these questions. Re-lubrication while hearing the grease
flowing into the bearing’s raceway gives the conviction that grease has
arrived where it should arrive. Based on manufacturer’s guidelines and
the results of trending the bearings for some time, grease quantities to
be applied can be determined. Also, when hearing that a bearing doesn’t
need grease, don’t! By doing this, condition based re-lubrication starts
to take place as part of the re-lubrication program. This is true for
any rotating component!
Ultrasound is the
result of friction. This friction causes low energy ultrasonic waves.
These waves will not travel far from the source, and can’t be heard by
the human ear. The ultrasonic signal is picked up by a sensor and
heterodyned to a signal the human ear can hear. By simply listening via
a headphone to any rotating equipment you hear the ultrasonic signal of
the component. Some instruments can store the readings taken for data
trending purposes. Since an increase in ultrasound over time is a strong
indicator of increased wear this phenomenon can be used to say something
about the state of the component listened to, whether that is a bearing,
a gear drive or other rotating component in any machine. A slight
increase in ultrasound can also be a good indicator that the component
needs relubrication. After relubrication the sound level should drop
back to the historical level measured earlier. If not, the very
beginning of failure is detected. And when you know this, you can choose
to further analyze with vibration techniques, start intensified
lubrication countermeasures, or simply start ordering a replacement
component.
There are a lot of
considerations to be made and a lot of planning to be done before a
lubrication program can be put into place. The more the facts are known
before starting the program, the better the program turns out to be and
the quicker the program will have beneficial results.
A good program,
highly inspired engineers and the right tools are a guaranteed means to
reduce production and maintenance costs, unexpected production stops,
quality non performances and will lead to beating the competition.
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