Lecture 1 - part 1.pptx

 1st –Lecture
 Maintenance and its types
 Introduction of Vibration
 Introduction of Acoustic Emission Inspection
 Introduction to Thermography
 Introduction to Oil Analysis
 2nd – Lecture
 Introduction of Vibration
◦ What is Vibration?
◦ Why Monitor Machine Vibration?
◦ How is Machine Vibration Described?
◦ Vibration Spectrums
◦ Energy in Spectrums
◦ Lines of Revolution (LOR)
◦ Analysis Techniques
◦ Measurement Point Identification
◦ Locating Turning Speed
◦ Data Collection Techniques
 3rd – Lecture
 CORRECTIVE TECHNIQUES (BALANCING,
ALLIGNMENT LOOSENESS)
◦ Introduction to Phase
◦ Absolute & Relative Phase
◦ Imbalance & its Types
◦ Vibration Severity Standards
◦ Diagnostic Rules for Imbalance
◦ Misalignment & its Types
◦ Diagnostic Rules for Misalignment
◦ Looseness & its Types
◦ Diagnostic Rules for Looseness
◦ Diagnosis Summary
 4th – Lecture
 Failure Mode Analysis
◦ Bearing Defects (Roller Bearing)
◦ Bearing Defects (Slider Bearing)
◦ Belt Defects
◦ Gear Box Defects
◦ Pumps, Fans & Compressors
◦ Resonance
◦ Electrical Defects

Why Do We Do Maintenance
Overall Equipment Effectiveness (OEE)
Breakdown Maintenance
Predictive Maintenance
Maintenance Practices
Preventive Maintenance
Reliability Centered Maintenance (RCM)
Proactive Maintenance

Why Do We Do Maintenance
To fix broken or damaged machines.
Preventing machines from failing.
To meet production goals.
To Increase plant efficiency.
To avoid Catastrophic failure.
To avoid Secondary damage.
Comply with regulations.
To avoid Additional spare parts costs.
To avoid Unnecessary overtime.
To avoid Injury to workers.
To reduce cost of product.
Reasons

Is the purpose to fix machines that are broken or damaged?
Does this describe the real purpose of maintenance?
Can we view maintenance as being a way of preventing machines from failing
Do we do maintenance simply to comply with regulations or for insurance reasons?
Do we overhaul machines because they are “due for overhaul” whether they need it
or not?
Do we need to meet production goals and thus increase profitability?
When you are replacing the bearings in a motor, are you thinking of plant profitability?
Understand Our Goals
First!

Why Do machine fail ?
Improper
Designing
Manufacturing
Defects
Wrong
Installation
Poor
Maintenance
Imbalance Misalignment
Poor Lubrication
Acceptance
Testing
Overloading

Maintenance is a combination of all technical and administrative actions,
including supervision actions, intended to retain an item in, or restore it to, a
state in which it can perform a required function.
Activities
Repair
Replacement
Important for an item to
reach its acceptable
productivity conditions
Should be carried out
with lowest possible
cost
Maintenance

Designers drafting board
Poor maintenance practices and operating conditions
Machine Failure
Start
End
The
way
machine
is:
Manufactured
Installed
Overhauled
Failure
starts
with:
Specifications
Purchase
Procurement
&
Although not all BUT Some of these
factors can be controlled
Why machines fail ?

M
a
i
n
t
e
n
a
n
c
e
Maximising
Production
Minimising Energy
Usage
Optimising Useful Life
of Equipment
Providing Budgetary
Control
Optimising Resources
Utilisation
Reduce Breakdowns
Reduce Downtimes
Improving Equipment
Efficiency
Improving Inventory
Control
Implementing Cost
Reduction
Maintenance Objectives

 Depending on industry, maintenance costs can represent
between 15% to 60% of production.
 Estimated that one-third of all maintenance costs is wasted due
to unnecessary or improperly carried out maintenance. (~$60bn
out of $200bn).
 Difficult to compete with countries like Japan who have more
advanced maintenance strategies.
Importance of Maintenance

Maintenance Plan
On Failure
Fix it when it fails
Fixed Time
Maintain Based upon
Calendar
Condition Based
Maintain Based Upon
known Condition
Design Out
Identify & design
Out root cause of
failure
Maintenance Strategies

Reactive
Maintenance
Preventive
Maintenance
Predictive
Maintenance
Proactive
Maintenance
Reliability Based
Maintenance
Maintenance Strategies

If it isn't broke, don’t fix
it
No money spent on maintenance until machine or structure stops
working
Sounds Interesting .....
BUT
AT THE COST OF HUGE MAINTENANCE BUDGET!
Reactive Maintenance

Control is lost when breakdown maintenance is employed.
This is why it is often termed“ reactive” maintenance.
The plant reacts or responds to equipment failures rather
than anticipating them, planning for them or avoiding them
altogether.
reakdown Maintenance as Reactive Maintenan

Objectives
Maximisation of the
effectiveness of all critical plant
systems
Elimination of Breakdowns
Elimination of Unnecessary
Repairs
Reducing deviations from
optimum operating conditions
Steps involved
Fault Detection
Fault Isolation
Fault Elimination
Verification of
Fault Elimination
Several actions should
be taken, like adjusting,
aligning, calibration,
removing, or replacing

Effective
Planning
Depends
On
Skills of the planners
Well developed
maintenance database
Complete repair
procedures
Required labour skills,
specific tools
Prerequisites of reactive
maintenance

Reactive Maintenance is:
 Unplanned,
 Disruptive,
 Interruption
 Costly ineffective response option
Allowing this to prevail as an existing response increases the
overall cost and complexity of managing the system.
Highly Undesirable

When a plant is primarily using run to
failure maintenance we can say they are
caught in a reactive mode
They are always reacting to problems and
situations.
When visiting a plant in this mode one will
find it to be dirty and disorganized.
Employees will complain that they are
over worked or always “too busy” to
change how they do things.
There will likely be a high rate of injuries,
spills, fires and other damage caused by
unexpected failures.
A Plant in Reactive Mode

Due to reactive mode, Plant is always
behind and trying to catch up to meet
production demands.
They are not running the plant, the plant is
running them and this is a frustrating
environment to work in.
Most of us prefer to work in a predictable
environment in which we feel we are in
control of the situation.
A plant in reactive mode is clearly not that
type of environment.
Morale will likely be low.
A Plant in Reactive Mode

 Requires no pre-care of the plant
 Little management apart from organizing labor and stores
 If applied correctly, it can be very cost effective
Advantages of Reactive
Maintenance are Outraged by its
Disadvantages
ADVANTA
GES:

 Most expensive maintenance
method
 No Failure warning:
 Safety threat
 Environmental Risk
 High spare parts inventory
 High overtime costs
 Long machine downtime
 Spare machines required
 Low production availability
 Large standby maintenance
team
 Knock-on effects on other
machines and overall loss of
production
 Secondary/Consequential
damage may occur
DISADVANT
AGES:
Bearing
Shaft
Pump

Time Driven
Maintenance
Time between maintenance decided on statistical
data
Hour of
Operations
Based On
Elapsed Time
Bath Tub Curve

Preventative maintenance is defined as regularly scheduled
repair of components and equipment.
It may consist of:
 Scheduled inspection
 Cleaning, lubrication
 Parts replacement
 Repair of components
Preventative maintenance is time based intervention according to
a prescribed schedule.

Bath-Tub Curve

The unfortunate reality is that there is a high probability of
failure immediately after an overhaul due to:
Infant Mortality
Poor
lubrication
Incorrect parts
being installed
Poor
alignment and
balance

If the maintenance is put off too long, the machine may fail
If the overhaul is performed too early, it becomes too
expensive, in labor, lost production and parts
Risk is Balanced Against Cost

Preventive
Maintenance
Routine
Maintenance
Running
Maintenance
Opportunity
Maintenance
Window
Maintenance
Shutdown
Preventive
Maintenance
•Maintenance activities
that are repetitive and
periodic in nature
•Lubrication, cleaning,
and small adjustment
•Maintenance activities
that are carried out while
the machine or equipment
is running
•Activities that are
performed before the
actual preventive
maintenance activities
take place.
Set of maintenance
activities that are
performed on a machine
or a facility when an
unplanned opportunity
exists during the period of
performing planned
maintenance activities to
other machines or
facilities.
Set of activities that are
carried out when a
machine or equipment is
not required for a definite
period of time.
Maintenance
activities that are
carried out when
the production
line is in total
stoppage
situation.
Preventive Maintenance types

 Reduces failures (compared to the on-failure strategy)
 It uses the workforce cost-effectively with planned work
schedules
 Allows work to be planned well in advance
 It can only be applied effectively on fixed time intervals where the
deterioration is age related
Scheduled maintenance costs are
around one-third of run-to-failure
costs
ADVANTA
GES:

 The maintenance activity and associated costs will increase
 Generally based on bathtub curve – not reliable in many cases.
 The actual maintenance activity can sometimes cause failures
itself
 May be replacing a component that still has useful life
 Treats all similar machines as same.
DISADVANT
AGES:

Regular Machine
Monitoring
Technology Skills
Diagnostic Data
Performance Data
Maintenance
Histories
Operations Data
Design Data

Machines warn about their failure

80
82
84
86
88
90
92
94
25 30 35 40 55 60 65
%
Predictive maintenance improves production line performance
Predictive maintenance in % of total maintenance
Machine
availability
in %
Machine Availability in Predictive Maintenanc

This include most rotating machines with rolling element
bearings. We
don’t know when the bearings will fail but they do let us
know when they are damaged or failing.
The plant is no longer in a reactive mode, so
most work is planned
Less overtime and workers are not
stressed out
They come in to work every day and they
know what they need to do, there are few
surprises
Neat and clean workplaces
Plant in Predictive Maintenance

 Design of system
 Monitoring equipment
 Staff training
 Labor costs for measurement and analysis
COST
S:
 Elimination of unexpected & Secondary breakdowns
 Increased time between services
 Reduction of spare part stock
 Reduction in insurance premium
SAVIN
GS:

ADVANTA
GES:
 Equipment can be shut-down before severe damage occurs
 Alternatively, equipment can be run to failure if desired
 Production can be modified to extend the unit life – For
example:
Decrease the load on equipment so that it can
continue to run until the next planned plant
shutdown
 The required maintenance work can be planned, with labor
organized, spares assembled, etc.
Reliability
Quality
Profitability
Productivity

Extremely Costly if
Implemented
Incorrectly!
The drawback of predictive maintenance is that it depends
heavily on information and the correct interpretation of the
information.
DISADVANT
AGES:

Elimination of conditional failures through the identification of
the root cause condition that initiates the failure cycle.
GETTING TO THE ROOT OF PROBLEM
It commissions corrective actions
aimed at the sources of failure.
Designed to extend the life of
mechanical machinery

• A predictive maintenance program gives a warning of bearing failure,
and then the replacement can be ordered and a repair scheduled.
• That's great, but why did the bearing fail?
Justification of Proactive Maintenance

Similar behavior as in care of predictive maintenance
The condition of most of the plants assets is known
because CM technologies are being employed.
Machines should not fail unexpectedly - at least not
frequently.
One removes the root causes of many failures thus
increasing reliability and extending the life of the
machines
Plant in Proactive Maintenance

 One-off maintenance activity
 It reduces failures
 It will lead to increased production
 It will remove or reduce the need for maintenance
ADVANTA
GES:

 Large design changes can be costly
 Plant outages may be required to effect design changes
 Unless root causes of failure are fully understood, changes
may be ineffectual, or potentially detrimental
 There are sometimes unknown ‘knock-on’ effects of design
changes that can cause further difficulties later on
DISADVANT
AGES:

Condition-Based
Maintenance
Proactive Maintenance Predictive Maintenance
Root Causes Failure Symptoms & Faults
Balancing/Alignment Tools
Viscosity/Contamination
Monitoring
Wear Debris Analysis
Vibration Analysis
Thermography/MCS
Fault Free Machine
Life Extension
Early detection of Faults &
Failures
Strategy
It Looks For!
Example
Technologies
Employed
Benefits
Sought
Condition-Based Maintenance

Maintenance
Strategy
Technique Needed Human Body
Parallel
Proactive
Maintenance
Monitoring and
correction of failing
root causes, e.g.,
contamination
Cholesterol and blood
pressure monitoring
with diet control
Predictive
Maintenance
Monitoring of vibration,
heat, alignment, wear
dibris
Detection of heart
disease using EKG or
ultrasonics
Preventive
Maintenance
Periodic component
replacement
By-pass or transplant
surgery
Breakdown
Maintenance
Large maintenance
budget
Heart attack or stroke
Maintenance Strategy – Human Body Parall

 All four maintenance strategies are required to make an effective
Maintenance Plan.
 All four maintenance strategies have advantages when
implemented correctly.
 All four maintenance strategies have disadvantages when
implemented incorrectly.
 The appropriate strategy can only be chosen when the reasons
and consequence for equipment failures are fully understood.
Key Facts

1. Elimination of plant downtime
2. Condition of equipment known. Machinery condition information
provides status of existing and future plant capacity.
3. Commitment to extend the useful life of equipment through the
identification and elimination of failure modes
4.Development of work teams and team goals combining
maintenance and operations.
5. Maintenance & Operations are partners in providing and
utilising plant capacity.
10 goals of Reliability Centred Maintenanc

6.Maintenance is knowledge–based , providing for improved
decision making.
7. Commitment to create a learning organisation where mistakes
are not repeated.
8. Development of a systematic approach for each situation (predictive,
proactive, preventive and reactive).
9. Both management and operation staffs develop a plan for action
and improvement.
10. Maintenance function has long term objectives, where the
gains are sustained year after year.
10 goals of Reliability Centred Maintenanc

 Increased Productivity (2-40%)
 Reduced maintenance expense (7-60%)
 Improved product quality (rework & scrap rates reduced 5-
90%)
 Extend equipment life (>1- 10x life extension)
 Reduced spares inventory (10-60%)
 Increased inventory turns (up to 75%)
 Reduced finished goods inventory
 Reduced energy consumption (5-15%)
 Increased safety & environmental protection
Benefits of Reliability Centred Maintenanc

Fix it when its brake.
(Reactive
Maintenance)
Time based
Maintenance.
(Preventive
Maintenance)
Inspect the condition of
Equipment. (Predictive
Maintenance)
Find the root cause of
failure (Proactive
Maintenance)
Predictive + Proactive
Reliability (Based
Maintenance)
Key Points

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