The Good Maintenance Guide
1. Introduction
1. Maintenance Management
1.1 Definitions (1)
Asset
Any item of physical equipment
1. Maintenance Management
1.2. Definitions (2)
Asset function
- What users expect from their assets
(output, speed, safety, environmental
integrity, quality ..)
- The level of performance which the
users require when the asset does
its function
1. Maintenance Management
1.1. Definitions (3)
Asset failure
Situation where the asset is no
longer capable of fulfilling one or
more of its intended functions
1. Maintenance Management
1.1. Definitions (4)
Maintenance
Any activity carried out on an asset in
order to
- ensure that the asset continues to
perform its intended functions
- repair the asset
1. Maintenance Management
1.1. Definitions (5)
Maintenance management
The coordination, control, planning,
execution and monitoring of the right
equipment maintenance activities of
manufacturing operations
1. Maintenance Management
2. Objectives
• Preserve asset functions
• Avoid the consequences of failure of the
asset
• safety failures: endanger personnel and
equipment
• operational failures: result in product loss and
cost of repair
• non-operational failures: result in cost of repair
1. Maintenance Management
3. Evolution (1)
Definitions
• Availability
• time available for production - downtime
time available for production
• = a measure of the equipment uptime
• Reliability
• the probability that equipment will not fail in a
given time period
• = a measure of the frequency of downtime
1. Maintenance Management
1.3. Evolution (2)
Expectations of the maintenance function
1930 - 1950
Fix it when it breaks
1950 - 1980
Higher availability
Lower costs
Longer asset life
1980 - 2000
Higher availability
Lower costs
Longer asset life
Higher reliability
Better product quality
Safety integrity
Environment integrity
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1. Maintenance Management
1.3. Evolution (3)
Maintenance techniques
1930 - 1950
Fix it when it breaks
1950 - 1980
Scheduled
maintenance
Planning systems
Computerization
1980 - 2000
Condition monitoring
Failure modes and
effects analysis
Computerized Maint.
Management Systems
RCM - TPM (see later)
The Good Maintenance Guide
2. Maintenance Management Functions
2. Maintenance Management
Functions
2.1. Overview
•Physical asset management
•identification of assets
•recording of information
Maintenance strategy
conducting the right maintenance
Maintenance planning &
scheduling
work order management
•Resources management
•people, spare parts, tools
•Performance measurement
The Good Maintenance Guide
2. Maintenance Management Functions
Physical assets management
2. Maintenance Management
Functions
2.2. Physical Assets Management
Maintenance is concerned
with Assets
• Preservation of asset
functions
• Renovation of assets
• Life extension of assets
• Replacement of assets
Maintenance Management Functions
2.2. Physical Assets Management
• Assets must be identified
• use an asset hierarchy to identify your assets
• example
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plant
area (packing area)
equipment (belt conveyor)
item (gear box)
part (bearing)
• standardize the equipment descriptions
Maintenance Management Functions
2.2. Physical Assets Management
• Asset information must be recorded
• record all equipment maintenance activities
• assign all maintenance costs
• establish and effectively use a documented
history for each equipment
The Good Maintenance Guide
2. Maintenance Management Functions
Maintenance strategy determination
Maintenance Management Functions
2.3. Maintenance strategy determination
Strategy
Maintenance type
Fix it when it fails
Emergency maintenance
Corrective maintenance
Time based (calendar time
or running time)
Preventive maintenance
Condition based
Predictive maintenance
Equipment redesign
Modification maintenance
Failure finding
Routine maintenance
Maintenance Management Functions
2.3. Maintenance strategy determination
How can we assure that the maintenance
conducted is the right maintenance and that
it produces the required equipment
reliability?
Reliability Centered Maintenance (RCM)
Maintenance Management Functions
2.3. Maintenance strategy determination
RCM definition
RCM is a technique for reviewing equipment
failures and for determining the right
maintenance tasks
Maintenance Management Functions
2.3. Maintenance strategy determination
RCM properties
• RCM ensures that all performed maintenance
is cost effective
• RCM contradicts the traditional precepts that
the reliability of equipment is directly related
to operating age
• RCM focuses on preserving the functions of
equipment, not on preserving the equipment
itself
Maintenance Management Functions
2.3. Maintenance strategy determination
RCM steps
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Select the most critical equipment
Determine the functions of the
equipment
Establish performance standards
Determine type of failures
Identify causes of failures
Define effects of failures
Categorize the effects of failures
Identify appropriate maintenance
tasks
Establish an overall maintenance
plan
Maintenance Management Functions
2.3. Maintenance strategy determination
RCM implementation
• Operations
• identifies the functions and performance standards
• Maintenance
• identifies the types of failures
• defines the most appropriate condition monitoring
techniques
• builds a program
• Maintenance and operations
• collaborate on the consequences of identified failures
• carry out the program
Maintenance Management Functions
2.3. Maintenance strategy determination
Some important notes about failures
• A part of equipment has suffered a failure when it is
no longer capable of fulfilling one or more of its
intended functions
• A failure mode or cause is any event which causes a
failure
• A failure pattern is the relationship between the
probability of failure of an item, and its age
• There are six distinct failure patterns, one of which
is the bathtub curve
Maintenance Management Functions
2.3. Maintenance strategy determination
Probability
of failure
Bathtub curve
Manufacturing
& installation
Useful Life Period
defects
Operating time
Wear-out Period
Maintenance Management Functions
2.3. Maintenance strategy determination
Failure patterns
A (bathtub curve)
- starting
with manufacturing and installation defects,
going to constant failure probability, ending in a
wear-out zone
- example: new machines
Maintenance Management Functions
2.3. Maintenance strategy determination
Failure patterns
B
- constant
failure probability, ending in a wear-out zone
- example: abrasion
Maintenance Management Functions
2.3. Maintenance strategy determination
Failure patterns
C
- slowly
increasing probability of failure
- no identifiable wear-out age
- example: fatigue
Maintenance Management Functions
2.3. Maintenance strategy determination
Failure patterns
D
- low
failure probability when the item is new
- rapid increase to a constant level
Maintenance Management Functions
2.3. Maintenance strategy determination
Failure patterns
E
- constant
failure probability at all ages
- example: rolling element bearings
Maintenance Management Functions
2.3. Maintenance strategy determination
Failure patterns
F
- starts
with high failure probability
- drops to a constant level
Maintenance Management Functions
2.3. Maintenance strategy determination
• The most appropriate equipment
maintenance strategy can be determined by
• The failure pattern that applies to a given failure
mode
• Mean Time between Failures (MTBF): the number
of failures in a given time period, divided by the
time that the equipment was operating in that
period
• FMEA (Failure Mode and Effects Analysis):
identify all the events which are reasonably likely
to cause each failed state
Maintenance Management Functions
2.3. Maintenance strategy determination
Maintenance types: emergency maintenance
• Definition:
• maintenance work requiring immediate response
from maintenance employees
• Goal:
• solve downtime, safety risk, danger or damage
• Properties:
• unplanned
• creates peaks and valleys in the work load
• expensive
• requires emergency spare parts purchasing
Maintenance Management Functions
2.3. Maintenance strategy determination
Maintenance types: corrective maintenance
• Definition:
• restoring an asset to a preserved condition
• Goal:
• improve quality or performance
• Properties:
• planned
• a work order has been created
• the work is prepared
Maintenance Management Functions
2.3. Maintenance strategy determination
Maintenance types: preventive maintenance
• Definition:
• replacements or overhauls scheduled on elapse
of calendar time or elapse of running time
• Goal:
• reduce downtime and breakdowns
• extend the life of the equipment or system
• Properties:
• planned & prepared
• correct failure probability must be known
• original reliability must be restored
Maintenance Management Functions
2.3. Maintenance strategy determination
Maintenance types: routine maintenance
• Definition:
• short periodic work carried out pre-dominantly
on-line
• ex: inspections, lubrication, adjustments
• Goal:
• reduce downtime and breakdowns
• extend the life of the equipment or system
• Properties:
• planned & prepared
Maintenance Management Functions
2.3. Maintenance strategy determination
Maintenance types: predictive maintenance
• Definition:
• comparing the trend of measured physical
parameters against known engineering limits
• Goal:
• detecting potential and hidden failures (see next
slide)
• Properties:
• planned
• condition based
Maintenance Management Functions
2.3. Maintenance strategy determination
Maintenance types: predictive maintenance
• Types of failures
• functional failure: the inability to meet the
specified performance standard
• potential failure: a physical condition which
indicates that the failure process has started
(metal particles in oil)
• hidden failure: failure is not apparent until the
function is attempted
Maintenance Management Functions
2.3. Maintenance strategy determination
Maintenance types: predictive maintenance
The majority of failures do not occur instantaneously but develop over
a period of time (P-F Curve)
100%
Operating
Condition
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Failure starts
to occur
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Failure can be
P
detected
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Failure has
occurred F
- Possible actions at P
- prevent functional failure
- avoid consequences of the failure
Time
2. Maintenance Management Functions
2.3. Maintenance strategy determination
Maintenance types: predictive maintenance
• Diagnostic devices:
• Vibration analysis
• Lubrication analysis
• Infrared thermography
• Ultrasonic testing
• Shock pulse methods
• Oil analysis
• Coolant analysis
• Wear particle analysis
The Good Maintenance Guide
2. Maintenance Management Functions
Maintenance planning and scheduling
2. Maintenance Management Functions
2.4. Maintenance planning and scheduling
Definitions
• Work request
• formal request to have work done.
• Can be filled out by a production or maintenance
employee
• Work order
• Written authorization to proceed with a repair or
other activity to preserve an asset function
2. Maintenance Management Functions
2.4. Maintenance planning and scheduling
• Work planning
• assigning work orders to a time period
• plan resources
• Work scheduling
• arranging the sequence of the work orders
• considerations
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priority
availability of craftsperson
availability of material and equipment
desires of the operating personnel
2. Maintenance Management Functions
2.4. Maintenance planning and scheduling
Workflow
• Work identification
• by operation or maintenance personnel
• Work order creation
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work order number
date
originator
asset identification
short description
priority
approved by
2. Maintenance Management Functions
2.4. Maintenance planning and scheduling
• Work preparation
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accounting code
job description (sequence of events)
crafts required
material required
tools required
safety and environment considerations
estimated hours
2. Maintenance Management Functions
2.4. Maintenance planning and scheduling
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Work execution
Progress tracking
Work analysis
Recording information
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nature of occurrence of the failure
nature of the failure
nature of the repair
total downtime, labor-hours and spare parts
2. Maintenance Management Functions
2.4. Maintenance planning and scheduling
Work preparation
• Work preparations are important
• facilitate estimation
• assure that the job will be done in the most
efficient manner
• contribute to training by indicating the
methodology of the job
• the preparation can be used the next time the job
has to be executed
2. Maintenance Management Functions
2.4. Maintenance planning and scheduling
Priority system
• A priority system is established to ensure
that the most needed work orders are
scheduled first
• Example of priorities
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0: emergency or safety work
1: work to start within 24 hours
2: work to start within 1 week
3: work to start within 1 month
4: turnaround or overhaul
2. Maintenance Management Functions
2.4. Maintenance planning and scheduling
Backlog management
• What is Backlog:
• all work available to be done. Backlog work has
been approved and prepared
• The backlog must be used as a tool to make
decisions
• informs management about future needs for
maintenance (contracting, more or less
personnel)
• must be effectively managed so that it does not
grow to an unmanageable size
The Good Maintenance Guide
2. Maintenance Management Functions
Resource management
2. Maintenance Management Functions
2.5. Resource management
• Resources
• people
• spare parts
• tools
• Resource management
• matching the resources to the workload
2. Maintenance Management Functions
2.5. Resource management
People
• Utilization of people can be improved by
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managing the size of the backlog
contracting
shift from unplanned to planned work
smoothing the workload
2. Maintenance Management Functions
2.5. Resource management
Spare Parts
• The optimal balance between the cost of
holding and the cost of stockout must be
achieved
• Classification of spare parts
• Function
• Usage rate
• fast moving
• slow moving
2. Maintenance Management Functions
2.5. Resource management
• Spare parts management
• the right parts in the right place at the right time in
the right quantity
• create an equipment history analysis
• identify dormant or excess stock items
• establishment of workable stock levels, controlled
by supply lead-time and usage
2. Maintenance Management Functions
2.5. Resource management
Tools
• Tools are not consumable
• Tools must be:
• monitored
• maintained
• replaced on time
The Good Maintenance Guide
2. Maintenance Management Functions
Performance measurement
2. Maintenance Management Functions
2.6. Performance measurement
You can’t manage what you don’t measure
• Maintenance is often organized and
performed without proper measures to
determine its impact on the business’s
success
• You need
• consistent and reliable data
• high quality analysis
• clear presentation of the information
2. Maintenance Management Functions
2.6. Performance measurements
General
• Actual budget versus forecast
• Maintenance costs
• overhead, labor, contractors, spare parts
• as a % of sales
• per unit produced
• Safety and environmental performance
2. Maintenance Management Functions
2.6. Performance measurements
Organization
• Ratio of contractors to company employees
• Ratio of production to maintenance
employees
• Maintenance employees per supervisor
• Maintenance employees per planner
• % overtime hours
• % absenteeism
2. Maintenance Management Functions
2.6. Performance measurements
Spare parts
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Inventory turnover
Inventory accuracy level
Inventory service level
% downtime due to stockouts
Materials versus labor ratio
Dormant stock items
Excess stock items
2. Maintenance Management Functions
2.6. Performance measurements
Work order management
• Work order lead time
• Workload (backlog) level
• by craft
• by priority
• by type
• Man hours per work order
• Daily schedule completion
• % emergency, corrective, preventive and
predictive maintenance of total activity
2. Maintenance Management Functions
2.6. Performance measurements
Equipment
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Overall Equipment Effectiveness
Reliability
Availability
Maintainability
Mean time between Failure
Costs for each asset center
Return on investment
The Good Maintenance Guide
3. CMMS
3. CMMS
3.1. Definition
CMMS
=
Computerized Maintenance Management
System
(computer replaces manual systems)
3. CMMS
3.2. Basic modules
• Asset register
• documentation
• equipment data management
• multi-level hierarchical filing system
• Work order management
• History file
• required for feedback
• maintenance of work preparations
• reporting
• Spare parts inventory control
3. CMMS
3.3. Optional modules
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Budget analysis
Invoice / ordering control
Condition Based Maintenance Manager
Failure analysis
3. CMMS
3.4. Trends
• Internet-enabled
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bringing information and training to the shop floor
transferring analysis data to equipment suppliers
online equipment monitoring
purchasing of spare parts (e-procurement)
software vendors will host CMMS on their own
servers (Application Service Providers)
3. CMMS
3.4. Trends (2)
• Data Input:
• Use of handheld computers by technicians
• Interfacing with bar code terminals
• Integration of Supply Chain Software and
CMMS
4. Total Productive Maintenance
• TPM is a company-wide team-based effort to
build quality into equipment and to improve
overall equipment effectiveness (OEE)
• TPM principles, components, implementation
and benefits are handled in detail in our
Good Maintenance Guide
5. RCM versus TPM
RCM is strong in determining what
maintenance to do, while TPM is all
about improving rather than merely
maintaining your processes
The Good Maintenance Guide
6. Good Maintenance Management
6. Good maintenance management
Principles
• Maintenance is recognized by management as
an integrated, essential part of production
• Continuous improvement programs are in
place
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performance is evaluated
reasons for downtime are analyzed
corrective actions are taken
progress is measured
6. Good maintenance management
• There is a commitment
to improve the ratio of
planned versus
unplanned work
• There is an emphasis
on training
• Operators are involved
in the maintenance of
their equipment
6. Good maintenance management
Benefits
• Equipment
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downtime reduction
smoother running
reduced waste
higher return on
investment
• increased equipment life
• repair history available
• People
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more efficient operation
balance of workloads
reduced overtime
increased cooperation
between production and
maintenance
departments
• Spare parts
• lower inventory levels
• lower usage
The end