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The typical
industrial lubrication program lacks order, structure, continuity
and respect, even though the ideas and practices have been around
for 100 years. Billions of dollars are spent annually to replace
lubricated machinery components that have worn out due to the
inability of the lubricant and the lubrication process to perform
the required task.1 In addition to that expenditure, millions
are spent analyzing lubricants at in-plant and commercial laboratories
for the purpose of identifying evidence of failed lubrication.
Further,
this is one area of plant operations that can yield a powerful
return on a meager investment. Case in point: a typical maintenance
budget in a capital-intensive operation (steel, paper, rubber,
automotive, etc.) can be approximately divided into two parts:
labor (+/- 55 percent) and materials (+/- 45 percent). Each part
can be further split. The labor component can be divided roughly
into standard (35 percent) and overtime (10 percent) labor. The
materials portion can be divided roughly into three sections.
For the sake of argument, we will line item lubricants (2 percent),
miscellaneous materials (13 percent) and MRO supplies (40 percent).
From this
it can be seen that the cost of the lubricant is one of the smallest
line items in a typical budget, at 1 to 3 percent; yet the manner
in which this budget is applied has an immediate and potentially
significant impact on the balance of the maintenance budget (overtime
and OEM lubricated component purchases). Any improvement in this
sliver of the budget ($100K to $300K in a $10 million budget)
could produce a leveraged savings from one of the largest single
categories in the budget, that being overtime and material costs($2.5
million in a $10 million budget).
It is not
hard to conceive of a $100K investment in lubrication program
improvements yielding $400K in maintenance cost reductions in
overtime labor and replacement parts. It is not unusual to achieve
improvements with this degree of relative impact.
Aside from
large, broad-based forces that push formalized business strategies
- such as just-in-time delivery (JIT) and manufacturing-to-order
(MTO), ISO 9000 certification and global competition - there is
plenty of justification to formalize and standardize excellence
in lubrication.
What is preventing
this process from becoming a center of excellence in a manufacturing
environment? I propose that it is a combination of the following:
1. Lack of
understanding the importance of excellence in lubrication practices.
2. Lack of
understanding how to achieve lubrication excellence.
3. Lack of
reinforcement from senior management, including supporting the
expense of taking the time to develop procedures and train personnel
so that practices can be achieved.
The
Role of Management
Senior management needs to be sold on the benefits of lubrication
excellence. This is accomplished by showing, in clear and concise
terms, how their investment in this process will create value,
improve productivity, reduce cost and move the company toward
their strategic and financial goals.
As practitioners
of plant tribology, it is important to learn how to present a
case in a language that senior management will understand so that
everyone can see the same potential for gain. Net present value,
cash flow, return-on-investment and payback period are financial
forecasting methods that need to be fully understood in order
to justify new ideas for improvement.
The
Role of Knowledge
It has been said that the industrial world rides on a cushion
of oil equal to about 10 micrometers in thickness, about the diameter
of a blood cell.2
If this is
true, then our livelihood in a very real sense rides on a film
of oil that is invisible to the naked eye. To protect that livelihood,
our perspective needs to be recalibrated so it can be seen, and
then we need to learn to protect this very thin film. This is
accomplished only through training and personal study in the field
of focus. The more that is known about the dynamic clearance between
two mechanical surfaces, the better the foundation for building
effective procedures and habits around protecting that oil film.
What is an
effective lubrication procedure? A procedure is a step-by-step
guideline that directs the user through a task. Therefore, a lubrication
procedure would guide the user through a specific lubrication
task. There are many types of tasks, such as: manual bearing lubrication,
gearbox filling, gearbox checking, gearbox top-off, gearbox cleaning,
kidney loop filtration, sample collection, etc. Each of these
tasks will have some degree of uniqueness, as well as a lot of
overlap with other similar lubrication tasks.
When preparing
a lubrication procedure, consider the following:
1. Strategy
- how does the procedure support the broader maintenance strategy?
2. Purpose
- what needs to be accomplished?
3. Procedure
- how is the task accomplished, including the many details that
determine safety, efficiency and effectiveness?
Strategy
The lubrication program should not be an isolated island in the
sea of maintenance practices. Lubrication practices should align
concisely with the defined, supported goals of the larger maintenance
operation.
With increasing
demand for equipment availability (to support a make-to-order
production schedule), many operations have adopted a Reliability
Centered Maintenance (RCM) strategy. Through such a strategy,
they’ve identified where and how to devote their energy to
manage their equipment.
RCM is a process
used to determine what must be done to ensure that any physical
asset continues to do what its users want it to do in its present
operating context.3
Within this
strategy, decide which machines can run-to-failure. Other machines,
perhaps similar, must be managed to assure maximum availability.
To maximize a limited lubrication resource, the lubrication procedures
for a particular machine should fit the broader strategy for that
machine. For example, a gearbox on a conveyor may be designated
run-to-failure with an anticipated five-year life span, while
an identical gearbox on a similar conveyor may be designated as
process critical with the difference between the two units being
the material conveyed.
Should both
units be treated the same? Probably not. Depending on the number
of run-to-failure units on hand, it may be best to develop a procedure
to select a lifecycle fill strategy (lubed for life) that incorporates
the use of a high-performance lubricant in a sealed application
with no planned routine service. Conversely, while the reliability
expectation is higher for the other unit, consider using a product
that does not offer the extended lifecycle benefits if the intention
is to closely monitor the unit for signs of distress.
As we step
into the procedure development process, we need to confirm that
the practice for each system aligns well with the stated maintenance
goal for that system. This will lead to greater lubrication efficiency
and effectiveness at a reduced total cost (such as plant maintenance
optimization).4
Purpose
Keeping this strategy in mind, the purpose is to state what is
to be accomplished for the lubrication procedure. While there
is no single approach to defining the purpose and the individual
tasks for the procedure, certain specifics must be included to
remove ambiguity and assure compliance. The purpose should include
at a minimum:
1. The name
of the item to be addressed (example: A/N 10043CD conveyor drive).
2. The objective
of the work (semiannual coupling inspection and relubrication).
3. Identification
of the individual to perform the task (Lubrication Technician,
MLT Level I Certified).
4. Operational
and safety conditions (example: equipment must be locked out before
work can be accomplished).
5. The amount
of time allocated to the task.
The details
should identify what is to be done, where it is to be done, who
will do the work, tools and materials needed, special issues surrounding
the work (safety, operational) and how much time is allotted to
the task. In the process of devising and writing procedures, expect
to find major similarities between like components grouped by
maintenance strategy. A template can be created with a significant
amount of generic information or structure to facilitate the process
without diluting the results.
Procedure
While keeping the strategy in mind, the procedure needs to support
five principles, or tenets, historically referred to as the five
Rs of lubrication. The five Rs are:
1. The right
product,
2. The right
place,
3. The right
amount,
4. The right
time,
5. The right
attitude.
Digging for
details is a must for the first four Rs. Sometimes the details
are within easy grasp. Sometimes guidelines are developed as progress
is made and when the team has a better understanding of what is
needed. More likely than not, if we want world-class procedures,
we have to develop them in-house, perhaps with the aid of a consultant
or specialist. Let’s look at the questions that should be
asked for each of these five categories.
Right
Product
This pertains to the selection of the lubricant for an application.
The OEM should be the starting point for product selection by
viscosity grade and boundary film formation properties (AW, EP,
solids) for both oil and grease products. The OEM has probably
considered the speed and load required of the operating components
and has calculated a minimum viscosity for that condition. However,
because the OEM cannot hope to understand your specific operating
conditions, factor in actual conditions and modify the OEM baseline
recommendation to fit accordingly.
For instance,
is the gearbox rated for one speed but operated at another speed?
Is the gearbox in an elevated ambient temperature location, or
is there significant process temperature transferred throughout
the shaft to the gear case? Is there risk of manufacturing or
process contamination entering the lubrication compartment before
or during installation? Is the unit accessible? Does the unit
have heat control mechanism (heat exchanger, fan)? What lubricant
products are readily available to help meet the OEM mechanical
and environmental conditions that exist? Can the company accept
a specialty lube product for this single application?
The answers
to each of these questions must have a bearing on the lube product
that is finally selected. One point of interest: it is your equipment,
your lubricant and your maintenance strategy. You make the decision
that fits your budget and goals. Collect input from various resources
(such as the local distributor, OEM, lubricant manufacturer or
subject-matter expert) but use internal resources - the company
team - to make the final educated decision.
Right
Place
This decision is predetermined by plant and equipment design process
for the vast majority of applications. Nonetheless, confirm that
the details are correct. OEM guidelines are just that: guidelines.
Every single lubrication application point must be uncovered,
photographed, tagged and reinforced. This requires having people
at the equipment, looking at the drive train or process flow.
Often lube lines disappear under a slab of sheet metal, as can
be seen from the example in Figure 2.
Figure
2. Disappearing Lube Lines
Get
input from those who install and repair the components behind
that slab to know if the right product is going in and that it
is going where it is supposed to go.
A cross-functional
work team is key to running down all of these details. The operators
live with the equipment on a day-to-day basis and generally understand
what is missed and what is not.
Right
Amount
Assessing oil volume requirements is generally straightforward.
For instance, calculate the amount of oil that goes into an isolated,
splash-lubricated, wet sump gear case. The level does not change
much between stand-by and operating modes. Circulating oil systems
present a greater degree of difficulty because lubrication lines
contain oil outside of the reservoir. For circulating systems,
factor in the volume of lubricant in transit, and estimate an
operating level as well as a stand-by level.
Once the reservoir
is filled, the task is to maintain the right predefined level.
Grease lubrication is more challenging. Manual grease relubrication
is probably the single most out-of-control aspect of machinery
lubrication, but it doesn’t have to be that way. The right
amount can be calculated easily with a few measurements and quick
formulas or charts from bearing suppliers. After calculating the
component requirement from the design criteria, add an environmental
factor based on the actual installation, the lubricant properties
and the time available for relubrication. Many factors interrelate
to influence the volume and cycle. They must be considered in
the context to produce a whole picture.
The
Right Time
The timing of relubrication intervals is influenced by many of
the same factors that influence relubrication quantities. Start
with the OEM guideline and adjust to maximize the properties of
the lubricant within the context of the application and environment.
The environment will have a significant impact on grease relubrication
intervals but less so on oil lubricated equipment. The most difficult
part of this procedure is identifying the operating and design
details.
The
Right Attitude
Regardless of the level of efficiency and accuracy in defining
the physical properties and requirements for optimum lubrication,
the human element is the trump card. Well-defined but poorly followed
practices are of marginal value. Likewise, highly motivated people
without role definition will either find a way to define their
role or will loose interest.
The right
attitude boils down to a personal decision made by the lubrication
technician, but it is greatly influenced by the senior management’s
attitude toward the role. If a subliminal message of ‘oil
is oil and grease is grease’ is reinforced by low wage scale,
shallow job title, neglected training and refusal of access to
resources to improve the process, then inferior motivation and
inferior results are often present. Don’t underestimate the
significance of this.
When all is
said and done, after we have formed a maintenance strategy and
chosen to standardize lubrication procedures and done all of the
footwork and thinking necessary to make the best decision, and
then boiled those decisions down into a coherent, common sense,
concise procedure, the real work begins. It is not easy to achieve
day-to-day consistency in what is arguably a hot, dirty and difficult
work environment, but the rewards can be measurable, lasting and
substantial.
A
Dollar Saved . . .
The perpetual nature of the lubrication process offers both challenges
and rewards. The benefits and drawbacks are cumulative. By refining
the strategy, working through the details and devising high value
procedures, we can position ourselves to add long-lasting value.
Every dollar saved through a new lubrication improvement is saved
over and over again. This is called an annuity. This makes each
dollar saved worth much more than the face value of the initial
dollar saved.
The process
is both orderly and detail oriented. Consider operational circumstances
and then correctly identify the right product, the right place,
the right amount, the right time, and then apply these excellent
practices with the right attitude.
To achieve
and maintain a competitive position in a hyper-competitive world,
a company must work as a team to build value in each segment of
the process. The development of world-class lubrication standards
and practices is long overdue in many organizations.
It is hard
but honorable work and should be done.
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