Post on 22-Nov-2014
description
Three Primary Steps in Maintenance
Reliability Engineering
by Jim Taylor, CPE, CPMM
Director of Operations, Machinery Management Solutions, Inc.
www.machineryhealthcare.com
Key Takeaway: Reliability Engineering can be done by the
average maintenance professional
michaelcardus
You work in a small to medium size facility or plant.
California Cthulhu
You’re a Maintenance professional: an Engineer, a Maintenance Manager, Supervisor, Planner, or Crafts Person.
theakshay.
Low availability and repeat failures on your HVAC equipment is affecting your production and
customer service.
mlinksva
You want to either remove or detect failure causes to
manage the failures.
Goal
Managed
Avoided
Surprise Managed
Avoided
Surprise
Reliability Engineering principles provide a way to do that.
Measure Availabilit
y
FindBad
Actors
Perform Failure
Analysis
Develop Job Plan
Data Collection
Implement Job Plan
Repeat
One of your primary duties is
to improve Availability (Ao).
MTBF
MTTR
MLDT
FRACAS
What is Ao?
MLDTMTTRMTBF
FMTBAo
Availability is the proportion of time a system
is in a functioning condition
To do that you must increase
Mean Time Between Failures
(MTBF)
Czarcats
What is MTBF?
Average elapsed
time between failures
of an operating system
How do you calculate it?
Failures
HoursOperatingMTBF
_
Timeline from Wikipedia
How can you use it?
High MTBF can result from:
Design
Lack of training
Lack of proper tools
Lack of documentation
Lack of proper equipment
Lack of proper maintenance
Lack of proper parts
You also must reduce Mean
Time To Repair (MTTR)
B Rosen
What is MTTR?
Average time required to repair a failed component or system.
A measure of maintainability
How do you calculate it?
Failures
hoursrepairtimeActiveMTTR
__
How can you use it?
High MTTR can result from:
Design
Lack of training
Lack of proper tools
Lack of documentation
Lack of proper equipment
You also must reduce Mean
Logistics Delay Time
(MLDT)
zyphbear
What is It?
Average time a system is
awaiting maintenance
How do you calculate it?
Total delay time does not include active maintenance time
Failures
timedelayTotalMLDT
__
How do you use it?
High MLDT can result from:
Time for locating parts and tools
Delivery time
Locating, setting up, or calibrating test equipment
Dispatching personnel
Reviewing technical manuals
Awaiting transportation
To keep track of it all you need a
Failure Reporting, Analysis, and
Corrective Action Reporting System
(FRACAS).
English106
You must capture the details of the failure in enough detail to do effective failure analysis.
As found condition
Failed components
Operating parameters
Sequence of events
Fluid levels
Signs of over temperature or pressure
You must capture the times involved in order to calculate MTBF, MTTR and Ao.
Loading time = total time – planned downtime
Planned downtime = scheduled maintenance time + management time
Operation time = loading time – Unplanned downtime
Unplanned downtime = logistics delay time + active repair time
The data you capture must be stored in a way to make analysis as easy as possible.
fo.ol
After you have started collecting the data,
you are in a position to do Root Cause Failure Analysis
(RCFA).
www.isixsigma.com
For each problem, you
will find the cause,
the cost,and
a solution.
Define the effects of the failure and their costs.
Julia Manzerova
Unhappy Customer
Then rank the causes.
www.sixsigmaspc.com
Finally apply Reliability Centered
Maintenance (RCM) principles to
develop a corrective action.
You can use the RCM decision
tree to decide on the correct procedure.
Start at the top of the tree, assuming that the failure has occurred.
Develop & scheduleCondition Monitoring
task.Develop & schedule
PM task.Redesign system
or accept risk. Run-to-Fail
Will the failure havea direct and adverseeffect on safety or
environment?Will the failure have a
direct and adverseeffect on operations(quantity or quality)?
Will the failure result inother economic loss(high cost damage tomachines or system)?Is there an effective
Condition Monitoringtechnology/approach?
Is there an effectivePreventive
Maintenance task?
No
No
No
No
No
Yes
YesYes
Yes
Yes
3tr
ee
.vsd
Candidate
For -
As you can see, the decision tree is biased towards Condition Assessment.
Develop & scheduleCondition Monitoring
task.Develop & schedule
PM task.Redesign system
or accept risk. Run-to-Fail
Will the failure havea direct and adverseeffect on safety or
environment?Will the failure have a
direct and adverseeffect on operations(quantity or quality)?
Will the failure result inother economic loss(high cost damage tomachines or system)?Is there an effective
Condition Monitoringtechnology/approach?
Is there an effectivePreventive
Maintenance task?
No
No
No
No
No
Yes
YesYes
Yes
Yes
3tr
ee
.vsd
Candidate
For -
You may find redesign is best option in some cases.
Develop & scheduleCondition Monitoring
task.Develop & schedule
PM task.Redesign system
or accept risk. Run-to-Fail
Will the failure havea direct and adverseeffect on safety or
environment?Will the failure have a
direct and adverseeffect on operations(quantity or quality)?
Will the failure result inother economic loss(high cost damage tomachines or system)?Is there an effective
Condition Monitoringtechnology/approach?
Is there an effectivePreventive
Maintenance task?
No
No
No
No
No
Yes
YesYes
Yes
Yes
3tr
ee
.vsd
Candidate
For -
Make sure the procedure is both
effective and applicable.
An Applicable procedure
actually improves the situation.
An Effective procedure
costs less to do the procedure
than to suffer the failure.
Develop a corrective action plan in enough detail to enable
effective application.
The Job plan should have step by step actions.
Make sure you include all safety information.
Estimate all the resources needed.
You now have a Job Plan that should either eliminate the cause of the failures or give you
enough lead time to manage the failure.
We started with a piece of HVAC equipment that was causing problems.
mlinksva
We applied some basic RE principles to find the cause and develop a solution.
Measure Availabilit
y
FindBad
Actors
Perform Failure
Analysis
Develop Job Plan
Data Collection
Implement Job Plan
Repeat
We now must put that Job Plan into action and track the results.
We should see an increase in Ao and a decrease in costs.
Goal
Managed
Avoided
Surprise Managed
Avoided
Surprise
Key Takeaway:You can perform this kind of analysis.
theakshay.
Do it and you’ll avoid surprises, and you’ll have a happy customer.
Muffet
Within the next week pick a problem machine;Estimate the MTBF, MTTR, MLDT and availability, based on either history or subjective analysis. Pick a failure that is causing problems and perform a RCFA. Develop a way to manage that failure using RCM principles. Make sure the solution is both applicable and effective. Write and implement a Job Plan to correct the problem.
I’ll be glad to review your project if you’d like.
Your Next Step (Homework)
Questions?Comments?
Jim Taylor, CPE, CPMM
Jim.taylor@machineryhealthcare.com
765-366-4285
http://blog.machineryhealthcare.com