Beyond
“No Scheduled Maintenance” -Why maintenance
shouldn’t stop when RCM leads you to “no scheduled
maintenance”
by: Douglas
J. Plucknette of Reliability Solutions
When
I first began using Reliability Centered Maintenance
as a tool to develop a complete maintenance strategy
for a process or piece of equipment, I was bothered by
the phrase “No scheduled maintenance”.
I wasn’t that the phrase didn’t just come
out and say what it means, “Run to failure”, it
was that RCM as program leaves one with impression
that nothing more can be done.
It all stops here.
Run it to failure. Fix it when it’s broke.
Now, I understand the thought process Nowlan
and Heap were using, if a components failure cannot be
predicted through the use of on-condition maintenance,
prevented by using a preventive maintenance task, or
eliminated through redesign, the remaining strategy
would be “no scheduled maintenance”.
Fact is, if you’re an RCM analyst, you
work should not end here.
It was clear to me that something had been
left out of this process.
Looking at the reality of a manufacturing
environment, I asked myself this question:
Question:
“How would our
manufacturing director react if I told him the process
was down because we made the decision to run that part
to failure?”
Answer:
He/she would first absolutely crazy.
I can just hear it, “We planned on letting
this part fail!”
Then, he/she would want to know how long the
process would be down and do we have that part.
You
as the maintenance manager or supervisor would have
some real explaining to do, especially, if you
didn’t have the spare part on hand.
The missing piece in the RCM process was right
in front of my face on a daily basis.
When your business is in a sold out condition,
down time can be just as important as up time.
RCM was designed to maintain the functionality
of a process or piece of equipment. It never considered the function of reducing equipment
downtime.
Analyzing equipment functionality on its own,
RCM does a fantastic job of developing a maintenance
strategy. However, it falls short of developing a
complete maintenance strategy by failing to address
the reduction of consequences when “no scheduled
maintenance” is you strategy.
Consequence reduction is a key
expectation of maintenance in any manufacturing
environment. Downtime
is critical to our manufacturing partners and we are
expected to reduce it in any way we can.
So can consequence reduction be addressed as
part of an RCM analysis? The answer is yes! It
can be, and it should be!
Looking
at the RCM decision diagram below, run the failure
mode of a “Photo-eye fails” through the decision
diagram. Making
the assumption that the failure of this switch is
evident to the operator and has no effect on health,
safety or environment, we run the failure down through
the operational consequences portion of the decision
diagram. |
