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Teoría de mantenimiento, explicación de la teoría de mantenimento segun WCM
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Maintenance Theory
1
Dr. H. Yamashina
Professor Emeritus, Kyoto University
Fellow of RCA (The U.K.)
Member of Royal Swedish Academy
of Engineering Sciences
Contents :
1. Introduction
2. Why does equipment fail?
3. Mindset Change – Breakdown loss pyramid
4. The two types of breakdown
5. Principles of establishing an efficient and effective 5. Principles of establishing an efficient and effective
maintenance ?
6. The aims of Autonomous Maintenance and
Professional Maintenance
7. Component Maintenance
2
1. Introduction
The purpose of maintenance is in short to
maximize OEE (in case of a single
machine) or OLE/OPE (in case of a
continuous flow line as is seen in process
3
continuous flow line as is seen in process
industry).
The Calculation of O.E.E.I. Automatic machines
Operator’s jobs : material supply, take out of the products,
material transport, product transfer, watching,
trouble shooting, setup operation, etc.1) More than one machine / person
a) Calculation of the O.E.E. of each machine
b) Calculation of the standard cycle time
( = transfer time + machine time) of each machine( = transfer time + machine time) of each machine
c) The O.E.E. of the machines is the weighted average
of the O.E.E.’s of the machines
A B C
2) Integrated manufacturing system
a) Calculation of the O.E.E. of the system
(i.e., the O.E.E. of the bottleneck machine)
b) Calculation of the standard cycle time of the bottleneck machine
A B C D E F
Note : For the sake of improvement, the O.E.E. of
each machine of the system should be checked.
II. Semi-automatic machines
Operator’s jobs : on top of the above jobs mentioned in I, loading,
and unloading operations
1) More than one machine / person
a) Calculation of the O.E.E. of each machine
b) Case (I) : bottleneck ⇒ machine
calculation of the standard cycle time
(handling time + machine time)
Case (II) : bottleneck ⇒ operatorCase (II) : bottleneck ⇒ operator
calculation of the operator’s cycle time
Process
Equipmetnt A
Equipment B
Operator
1cycle
1cycle
Operation ( Set/unset)Automated
Equipment A
Equipment B
2) Integrated manufacturing system run by one operator
a) Calculation of the O.E.E. of the system
b) Calculation of the operator’s cycle time
Process 1cycle
B AA
B
C
D
walking operation automated
B A
C D
3) Integrated manufacturing system run by more than one
operators
a) Calculation of the O.E.E. of each machine
b) Case (I) : bottleneck ⇒ machine
calculation of the standard cycle time
(handling time + machine time)
Case (II) : bottleneck ⇒ operator
calculation of the operator’s cycle time
B AC
HGFE
D
If breakdown (reactive) maintenance is
more than 40 percent of your maintenance
department’s activities, you are not in the
maintenance business ― you are in the
machine repair business.machine repair business.
� Maintaining equipment in its desired state and continually
improving its productivity is the whole strategy behind WCM.
� If we only fix breakdowns, the machine will soon break down
again.
� We must put in place a system that maintains the desired
machine state.
Old Culture New Culture Created with WCM
Activities
Only the top few Pareto problems
are resolved, using any means
possible to make improvements.
All minor defects in a machine are
eliminated. Machine performance is
continually improved with the
methodical and repeated application
of WCM steps.
Improvements methods are
implemented by individuals or
Improvement methods are rigorously
defined and are expected to be implemented by individuals or
teams in any way that they see fit.
defined and are expected to be
implemented precisely.
Improvement in the
organization’s work methods and
processes are localized by each
team as they desire.
Improvements in the organization’s
work methods and processes are
coordinated by managers, so the
entire organization is learning and
benefiting from improved techniques.
Even improvement methods
themselves are continually being
improved.
Old Culture New Culture Created with WCM
Activities
Machine problems are resolved
one at a time, reactively. Ultimately,
improvements only occur in
systems that have failed.
A reliable and systematic
improvement process is applied to
a machine to address all
productivity losses proactively.
breakdowns are prevented before
they occur.
Only results are measured by Both results and the process used Only results are measured by
managers.
Both results and the process used
to obtain the results are measured
by managers.
Improvement steps are taken
as absolute-once completed they
are not revisited.
Improvements steps are revisited
as people’s skills improve, and
expectations for their performance
are raised.
Problems in dealing with breakdowns in the factoryProblems in dealing with breakdowns in the factory
1. Superficial fixing, simple
replacement of parts
・Merely repeating these measures will not lead to breakdown reduction. In particular, this tendency appears to
be prevalent in middle-ranking maintenance personnel.
2. Causes of breakdown not
examined in sufficient depth
・The real purpose of maintenance is to prevent reoccurrence.
・The most important method for reducing breakdowns and improving engineering and technical skills is to
persistently try to find root causes, and find comprehensive measures to deal with each individual incident.
・Are we neglecting to confirm what happened and why, due to the need of restarting production as quickly as
possible.
・It is important to develop the habit of a thorough examination of causes, with the cooperation of the production
department
3. Ignoring minor breakdowns ・breakdowns should not be ignored even if they only occur for a few minutes. If small incidents occur
repeatedly, they results in a big loss. Furthermore, minor breakdowns can be a precursor to a large breakdown.
4. No measures are being taken to
eliminate human errors
・Just because a fault is due to a human error does not mean that the fault will be solved simply by passing it on
to the production department. Measure to make sure the human errors do not occur and are not possible to
occur must be taken with the cooperation of the production department.
5. Not making enough effort to
apply solutions horizontally
・One breakdown suggests there may be potential breakdowns in other similar areas. Speedy efforts must be
made to find all similar areas, inspect them and address the problem with consistent measures.
6. Too much attention is paid to
the breakdowns which have
already occurred
・Although the most important thing is to take measures regarding the breakdowns which have occurred, most
breakdowns occur through deterioration.
・Be fully aware that fundamental measures to prevent breakdowns consist of the following two measures:
1) Clarification of operating conditions and compliance to conditions in use to prevent forced deterioration.
2) Clarification of the gap between the current state of the equipment and its desired state in order to identify
and resolve hidden defects.
7. Repair errors and the quality of
repair are not clear
・Maintenance operators must be maintenance professionals.
・Clarify responsibilities for repair errors and preventing their reoccurrence. Taking countermeasures will
improve engineering and technical ability.
It is necessary to confirm the quality after repair.
・Attention must be paid to the finest details to such a level as, the tightening of each single bolt, the
arrangement of every wire and the bending of each cotter pin. ( Confirm the number of repair errors )
8. Not enough efforts are paid to
chronic losses
From traditional
maintenance
To intelligent
maintenance
An overwhelming
maintenance workload
A manageable
maintenance workload
Many equipment
breakdowns
Very few equipment
breakdownsbreakdowns breakdowns
A marginally skilled
workforce that carries
out its daily routines
with little learning
A highly skilled
workforce engaged in
continuous
improvement activity
�The major problem of a plant is to utilize
equipment in an optimal way with well organized
maintenance.
� Equipment is designed to be reliable, but still liable
to breakdown because it consists of many
components and only when one of the components
Why Do breakdowns Occur?
components and only when one of the components
(A components) breaks down, it will break down.
� To eliminate breakdowns is technically possible,
but the problem is how to do it economically.
2 Why does equipment fail?
1. Deterioration
16
Normal machine component deterioration
- New Component
- Cosmetic Defects
Components
OK for good
machine
operation
Wear
an
d T
ear
Time
- Acceptable Wear and Tear
- Minor Defects
- Medium Defects
- Major Defects
Technical
people
must set
standards for
the way machine
components
“ought to be”
Acceptable deterioration limit
Non-standard parts
cause machine
losses
Wear
an
d T
ear
Machine fails
Troubleshoot the machine-
discover what has failed
Repair the machineBreakdown
restoration
Figure : The breakdown analysis process
Perform a breakdown
analysis-discover the root
cause of the breakdown
Design and implement
countermeasures to prevent
the breakdown from recurring
Breakdown
prevention
2. Increased stress applied to machine system
19
3. Insufficient strength within the machine system
20
Forceddeterioration
dete
riora
tion
DETERIO-RATION
INCREASED STRESS
breakdown TO
MAINTAIN BASIC
CONDITIONS
breakdown TO OBSERVE
OPERATING CONDITIONS
breakdown TO RESTORE
breakdow
Downtime Stratification
Why Does Equipment Fail ?
Breakdown Causes
21
deteriorationNaturaldeterioration
Time
Th
edegre
eof
dete
riora
tion
STRESS
INSUFFICIENTSTRENGTH
breakdown TO RESTORE
EQUIPMENT (ELIMINATE
DETERIORATION)
DESIGN
WEAKNESS
INSUFFICIENT
OPERATOR SKILLS
INSUFFICIENT MAINTENANCE
SKILLS
n
Breakdown
(function loss) Motor burns out
Minor Stoppage Motor overheating
(function reduction)
1111
10
3. Mindset change - Breakdown loss pyramid
Figure The Machine Loss Pyramid
Minor breakdowns Vibration causes
(no function bearing
reduction) deterioration
Hidden breakdowns Loose nuts and
(no function bolts
reduction)
30
Hundreds
22
Breakdown loss pyramid
Equipment
fails
Equipment runs,
is troublesome,
and produces
quality defects
•Equipment runs
•Quality is OK
•Productivity is low
•Breakdowns are imminent
Most organizations react here and
only restore equipment to the point of
getting the machine running again.
However, permanent improvement is only
attained when conditions at the base of
the pyramid which cause the breakdown are
improved.
Remaining chronic conditions will simply
combine in new ways to cause new machine
breakdowns.Causes and
By not attacking the root cause of equipment breakdowns, reactive
organizations are doomed to a cycle of permanent breakdown maintenance.
•Breakdowns are imminent
•Basic conditions are neglected
•Deterioration is unchecked
•Inherent design weakness exist
•Workers have inadequate skills
•Operating standards are not followed
breakdowns.
Figure Continually reacting to equipment breakdowns by restoring machine operation
does nothing to eliminate the root cause of machine breakdowns
Causes and
Potential
Improvement
For every
machine
breakdown there
are many
underlying
chronic
conditions
as causes
Equipment
fails
Equipment runs,
is troublesome,
and produces
quality defects
• Equipment runs
• Quality is OK• Quality is OK
• Productivity is low
• breakdowns are imminent
• Basic conditions are neglected
• Deterioration is unchecked
• Inherent design weakness exist
• Workers have inadequate skills
• Operating standards are not followed
Figure Minor machine defects are the true root cause of all machine breakdowns
Equipment
fails
Equipment runs,
is troublesome,
and produces
quality defects
•Equipment runs
•Quality is OK
•Productivity is low
WCM activities focus on elimination of the root causes of equipment breakdown.
Without this foundation of machine weaknesses, equipment breakdown will not occur.
•Productivity is low
•Breakdowns are imminent
•Basic conditions are neglected
•Deterioration is unchecked
•Inherent design weakness exist
•Workers have inadequate skills
•Operating standards are not followed
Analyze
Figure Without a foundation of eliminating minor defects, equipment breakdowns occur
Minor defects cause machine breakdowns
1.Minor defects hurt machine productivity by continuing to
deteriorate and growing into medium and major defects.
After all, every medium and major defect was once a minor
defect or resulted from minor defects. Left unattended,
minor defects only become worse. It is better to nip them
in the bud instead of letting them go until larger, more
difficult, more expensive repairs are required.difficult, more expensive repairs are required.
2.Minor defects impair equipment performance by causing
accelerated deterioration in other parts. Even though a
machine is running fine today with minor defects, these
defects often cause a faster rate of deterioration in
surrounding parts.
3. Minor defects hurt machine performance by interacting
with one another while they are all still minor in random
ways that, together, cause machine breakdowns.
These kinds of problems are notoriously difficult for
technicians to repair because they most often happen
intermittently – only when certain minor defects interact
in just the right way.
4. A single minor machine defect may, all by itself, cause a 4. A single minor machine defect may, all by itself, cause a
variety of machine breakdowns to occur without any
interaction with other minor defects. This is not a
frequent occurrence, and not every minor defect will
cause equipment breakdown or productivity loss all by
itself. Still, no one can tell which minor defects will
cause such performance problems; therefore, all minor
defects must be eliminated.
Most minor defects are detectable by our
human senses. We see them, hear them,
smell them, and feel them.
With experience, people performing these
inspections develop a “good eye” for the inspections develop a “good eye” for the
types of minor defects that can occur in their
equipment and learn to spot them with ease.
Note: Here you can see a clear limitation of
available CMMS’s.
�One of the principal goals of all maintenance
work is to keep every part in a machine “as it
should be― free of any minor defects.”
�Conditions that are not “as they should be” often
cause accelerated deterioration in other parts.
This increases machine downtime and the cost of
replacement parts, and wastes technician time. replacement parts, and wastes technician time.
�Machine deterioration, inadequate machine
design,or misuse of the machine can cause
abnormalities.
The lack of knowledge of a thousand
seemingly insignificant details
contributes in a huge way to many
equipment losses. This is the reason
Analyze
equipment losses. This is the reason
why most of CMMS’s do not work for
eliminating breakdowns
Mindset Change 1
�Minor equipment defects – once thought to be of no
importance to machine maintenance – are now considered
to be the root cause of almost all machine breakdowns and
are meticulously kept out of factory equipment.
�This requires operator involvement in machine cleaning
and inspection, once thought to be the sole province of and inspection, once thought to be the sole province of
maintenance technicians. It also requires technician
involvement in keeping minor defects out of equipment
areas not accessible to operators – a task not previously
performed by most equipment technicians.
Mindset Change 2222
�Creating and using a maintenance plan effectively requires using detailed checklists to carry out scheduled maintenance work.
�It also requires adhering in a disciplined way to checklist criteria during PMs.
�This is different from allowing individual technicians to decide �This is different from allowing individual technicians to decide what any given PM should consist of and how it should be performed.
�Equipment breakdowns can be prevented, despite many maintenance technician’s belief that machines will always break down, no matter what maintenance is performed.
�This self-fulfilling prophecy has kept most maintenance organizations locked into breakdown maintenance
Examples of minor defects that can be detected by human
senses include :
•Dirt of contamination
•Liquid or air leaks
•Loose or missing bolts and fasteners
•Gauges not reading in their “standard” range•Gauges not reading in their “standard” range
•Worn wiring insulation
•Wear in plastic tubing or similar parts
•Loose or deteriorated connectors
•Machine motions that are not smooth or accurate
• Switches that are not set in the correct positions
• Sensors that are not aligned or working correctly
• Fluid reservoirs that are not filled to the correct level
• Locking pins and devices that are missing or loose
• Safety guards that are not in place
• Surfaces showing signs of wear (detectable by the
repeated appearance of contamination)repeated appearance of contamination)
• Machines that sound abnormal
• Machines with unfamiliar odors
• Machines with unfamiliar vibrations
4. The two kinds of breakdowns
35
Breakdown of function stopping type
( This is likely to be caused by the growth of a minor defect )
● Breakdown which will cause the stoppage
of all the function of equipment
● Breakdown which is caused by a partial
function stopping and will eventually lead to
the stoppage of all the function of equipmentBreakdown
The two types of breakdownThe two types of breakdown
Breakdown of function deteriorating type
( This loss is liable to be bigger than the first type )
● Breakdown which is caused by the
deterioration of a partial function of equipment,
will not lead to the stoppage of all the function
of equipment, but will generate various losses
such as defectives, yield loss, minor stoppage
loss, idle loss, etc.
Breakdown
① Physically hidden defects: Defects which have not been attended due to the physical
structures of the equipment
・ Internal defects which go undetected by not being carried out overhaul.
・ Defects which can not be detected because of the shape and / or position of the part
(e.g. level gauge)
・ Defect which cannot be detected by dust, dirt, etc (such as a crack in the Banbury
mixer)
Hidden defectsHidden defects
Hidden defects are the ones which will eventually cause a breakdown but which have not
yet taken place detected.
There are 3 types of hidden defects.
① Physically hidden defects:
② Psychologically hidden defects Defects which are overlooked due to the low level of
awareness or skills among those in charge of the equipment
・ Defects which are actually visible, but have been neglected
・ Small defects which are ignored or not being dealt with because they are not
considered as important (minor defects)
・ Defects which are not noticed even though there are clear signs of abnormality.
(Importance of distinction between normal and abnormal)
③ Technically hidden defects Defects which have been unattended as design
weaknesses caused by insufficient technical checking
・ Strain inside the shaft (catastrophic breakdown)
・ These breakdowns rarely take place and must be addressed by involving technical
staff
② Psychologically hidden defects:
③ Technically hidden defects:
Enforce conditions required for equipment to
function correctly
Clarify and adhere to operation, control and
loading conditions for each piece of equipment
Identifying hidden defectsIdentifying hidden defects
Fiv
e issues f
or
identify
ing h
idden d
efe
cts
① Maintain basic equipment conditions
② Comply with conditions of use
Identify physically
hidden defects
Identify
Enforce the three basic conditions of
being clean, lubricated and tightened
Clean / touch
Tighten bolts and nuts
loading conditions for each piece of equipment
Fiv
e issues f
or
identify
ing h
idden d
efe
cts
③ Restore deterioration
④ Correct design weakness
⑤ Improve operating and maintenance skills
Identify
psychologically
hidden defects
Identify technically
hidden defects
Identify deterioration and restore them to their
original state
Clarify design weaknesses and implement
countermeasures
Clarify skills needed by people operating and
maintaining the machine, and raise technical
skills through education and training
5. Principles of establishing an efficient
and effective maintenance
�The major problem of a plant is to utilize
equipment in an optimal way with well organized
maintenance.
39
maintenance.
� Equipment is designed to be reliable, but still liable
to breakdown because it consists of many
components and only when one of the
components (A components) breaks down, it
will break down.
� To eliminate breakdowns is technically possible,
but the problem is how to do it economically.
Attempting to develop a maintenance
plan for each component is always
our first choice.
Machine redesign occurs only if an Machine redesign occurs only if an
acceptable maintenance plan cannot
be developed.
�Equipment breakdown does not occur suddenly
except it is caused by a human error. Equipment
breaks down when a component breaks down.
�There is a symptom before the breakdown takes
place. The problem to be addressed is how to detect
What is the Problem?
41
place. The problem to be addressed is how to detect
it economically.
� Identifying the component which will lead to a
breakdown before it breaks among many components
which constitute the equipment is a real issue.
The problems :
1.Few people understand the entire
process and the three elements (tooling,
process, layout) of production engineering
well.
2.Unless having experienced production on 2.Unless having experienced production on
the shop floor, the actual situations of
production cannot be understood.
3.Equipment is normally purchased. Few
engineers and technicians understand the
structure and mechanism of the equipment.
Structural drawing of Structural drawing of
the cylindrical the cylindrical
grindergrinder
Equipment is
normally
purchased.
Few engineers,
technicians and
operators operators
understand the
structure and
mechanism of
the equipment.
Identify !
44
� The first problem is to know the structure and mechanism of
the equipment.
� Problems to be addressed is how to detect the component
which will lead to a breakdown economically.
� This requires analyzing breakdown data in depth.
The first
problem is to
know the
structure
and
mechanism mechanism
of the
equipment.
A clever thief will find customers first
and then steal.
A poor thief will steal first and then look
46
A poor thief will steal first and then look
for customers.
Causes and
Potential
Improvement
1. Attempting to develop a maintenance plan for each
component is always our first choice.
2. Machine redesign occurs only if an acceptable
maintenance plan cannot be developed.
3. Replacing failed parts on a machine does nothing to
prevent the machine from failing again.
4. Machine repair without breakdown analysis simply
maintains the vicious cycle of breakdown maintains the vicious cycle of breakdown
maintenance.
5. One of the principal goals of all maintenance work is to
keep every part in a machine “as it should be― free of
any minor defects.”
6. Conditions that are not “as they should be” often cause
accelerated deterioration in other parts. This increases
machine downtime and the cost of replacement parts,
and wastes technician time.
7. Machine deterioration, inadequate machine design, or misuse of the machine can cause abnormalities.misuse of the machine can cause abnormalities.
(1) Machine classification into AA, A, B and C.
Note : Classification of machine and/or areas into
AA, A, B and C differs depending on the subject, i.e.,
AM, PM and QC and their countermeasure level i.e.,
reactive, preventive and proactive.
49
Risk (probability x possible loss in money)
Reactive Preventive Proactive
Money (loosing)
�Machine capacity data should be plotted
over a length of time that is significant for
production needs.
�Long-term averaging is of little use, because it
masks reliability problems that have significant
negative impacts on manufacturing productivity.negative impacts on manufacturing productivity.
(2) Machine ledger with component classification
into A, B and C.
A : When this component breaks down,
equipment breaks down.
B : Even if this component breaks down, its impact
is limited.
C : BM can be a good solution without problem.
51
C : BM can be a good solution without problem.
Robot Gripper Controller
Machine Machine �� SubSub--assembly assembly
80Robot180Robot1
Machine Ledger
Robot Gripper Controller
��Component Classification A B CComponent Classification A B C
Scheda RSM
Auxiliary Power Supply
Scheda DEVICENET
DNP
Batteria per RPU
8) Riduttore Asse 2
7) Riduttore Asse 1
6) Motore Asse 6
Collare STC0002
Modulo Input/Out
TURK
Braccio d'estremità
300mm STB0300
Cavetto comando
elettrovalvola
80Robot180Robot1
A 65%
B 19%
C 16%
MACHINE LEDGER
STEP 3Machine ledger
23
If you cannot see your entire
maintenance plan clearly and plainly
for every machine, you need to
improve the organization and visibility improve the organization and visibility
of your machine maintenance
scheduling plans.
(3) Measuring time between two consecutive breakdowns
� Initial breakdown -- design weaknesses, manufacturing
errors, installation errors, poor
maintenance
� Chance breakdown -- human errors
� Wear out breakdown -- professional maintenance
55
(4) Breakdown analysis to specify root cause(s)
-- Reactive : take countermeasures against the
recurrence of the same breakdown
-- Preventive : take countermeasures against
similar problems.
56
What Should We Do after Breakdown Is Solved to
Prevent It from Re-occuring?
57
①①①① breakdown to maintain basic conditions
Basic conditions
-- Clean
-- Lubrication
-- Tight and secure machines
58
②②②② breakdown to observe operating conditions
③③③③ breakdown to restore equipment. Equipment
deterioration is neglected.
④④④④ Design weakness
Residual strength of the machine components and the
kinetics of the systems are less than the forces applied.
Insufficient strength
⑤⑤⑤⑤ Insufficient operator skills
59
⑥⑥⑥⑥ Insufficient maintenance skills
⑦⑦⑦⑦ External reasons such as spare parts quality, etc.
187 EWO
BREAKDOWN ROOT CAUSE DISTRIBUTION
28%27%
20%
25%
30%
Specify the brands
standardization and
warehouse supply
Contact with
Related
departments
Review
procedures
AM Standarts
OPL
Example
60
8%
13%
18%
7%
0%
5%
10%
15%
20%
Exterior Effects
Spare Part
Quality/Missing
Errors due to
lack of
knowledge
Project
Weakness
Insufficient
Maintenance
Operations not
properly
executed
Lack of Basic
Conditions
procedures
for Preventive
MaintenanceTraining
both AM+PMManagement
of “AM Team”
CMMS - SAP
- EWO for all
breakdowns
- All EWO in CMMS
- Measurement between
PM to the breakdown
EWOMachine Ledger
CMMS - SAPor between the two breakdowns
- components
replaced
- time spent
EWO
action description - steps taken
- difficulties
- sketches
- components replaced
- safety issues
- spare parts problems
- ‘logistics problems’
potential
causes
list
5W + 1H
using N
EWO
causeverification
list
Prof. Yamashina:
However well in details the report is written it does not give the
real information unless the person who receives the report
sees the actual broken machine/ component.
Broken component tag Broken components area
TBF for components
expressed in:
- # working cycles
- working hours
- Is there PM and/or AM standard for this defect?
- Was it possible to identify defect before it occurred?
- Does the standard cover the identified defect?
- When recently the standard was planned?
- When recently the standard was performed?
- For when the next standard is planned?
Hu
ma
n
EWO
Hu
ma
n
Err
or
Sp
are
pa
rts
qu
ali
ty
Operating
conditions
Basic condition
Human error – in
usage
No PM
No AM
De
sig
n
we
ak
ne
s
-reveal potential defects
(PM / AM)
-improve and
extend solutions to other
similar components (FI)
Actions taken to:EWO
-extend created
knowledge (PD)
- improve future
machines (EEM)
- contact with parts
supplier
EWO
Direct material
problemsHuman Error
External factor
Design
weakness
Lack of knowledge of
Maintenance worker
Lack of
knowledge of
Operator
Error of
Design
weakness
Step 3 EEM
Energy
factors supply
root cause
Human error
Assembly Step
4 EEM
Human error
Installation
Step 5 EEM
Lack of /
ineffective
prevention
Lack of control
of operating
conditions
Lack of basic
conditions
Error of
Maintenance
worker
Error of
Operator
PM Calender
Prepared by the
67
evaluation of
“Machine Ledger”
ALL AA MACHINES
ARE COVERED BY
100% TBM
ACTIVITIES BASED ON
SMP
68
69
70
One specific shim Yoke must be installed on
Vacuum seals
must be leak-free
Cam followers must be
adjusted to a specific
clearance
Example : A slit valve assembly
71
Speed controls installed correctly to
regulate pneumatic cylinder exhaust
Each sensor located at a
specified location
Piston seals must be
leak-free and tight
Bolts must be properly
installed, torqued, and
locked
One specific shim
must be placed on
each side of the yoke
Yoke must be installed on
cylinder rod thread with
specified thread locker
Sensors should be on
left side
Item Required Condition Actual Condition Found
1 Speed controls installed correctly to
regulate pneumatic cylinder exhaust
Speed control valves installed backward
2 Each sensor located at a specified
location
Piston location sensors installed in wrong
position
3 Piston seals must be leak-free and
tight
Cylinder piston seals leaky and loose
4 Bolts must be properly installed,
torqued, and locked
Loose or missing bolts
torqued, and locked
5 One specific shim must be placed on
each side of the yoke
Center shim missing-cylinder not
perpendicular to yoke
6 Yoke must be installed on cylinder
rod thread with specified thread
locker
Yoke unthreading from cylinder and
striking machine surfaces
7 Vacuum seals must be leak-free Vacuum seals leaking
8 Cam followers must be adjusted to a
specific clearance
Cam followers misadjusted
9 Sensors should be on left side Cylinder 90°out of rotation
About half of all equipment
Analyze
About half of all equipment
abnormalities are manmade and not
caused by machine deterioration, as
most people suppose!
Pareto strat z tytułu awarii dla op. 30 Podłogi przedniej z
podziałem na przyczynę źródłową
0
2 000
4 000
6 000
8 000
10 000
12 000
14 000
Sta
tion o
p.
20
Rob
ot
30
R3
Rob
ot N
H3
OP
03
0R
01
22
0-2
.7
Tra
nsp
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er
pale
t
OP
030
PC
1
Kle
sz
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e
OP
03
0R
01
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48
Maszyna
[PL
N]
Brak/nieefektyw ność
prew encji
Niedoskonałość projektu
maszyny
Brak/nieefektyw ność
prew encji
Czynnik zew nętrzny,
części zamienne, detal
do produkcjiBłąd pracow nika UR
Root causes
Machines
Damaged component
Modified by the supplier
Human Error - assembly
B/C = 6
Modified by the supplier
0 breakdowns
BEFORE BEFOREAFTER AFTER
EEM
PM
Human Error - installation
Damaged componentsimulation sessions in suppliers laboratories
No material problem;
ROOT CAUSE:
• installation error
MP Info
0 breakdowns
Maintenance Analysis
Maintenance analysis is not a short form of 5-why analysis,
even though it might appear so at first glance. Rather, it is
a simple approach to designing a maintenance solution to a
machine breakdown. Two simple “whys” are asked and
answered:
1. Why did we not see this breakdown coming?
� Many breakdowns provide early warning signs, some of � Many breakdowns provide early warning signs, some of which may appear weeks or months ahead of the breakdown. Others may appear only hours or days ahead.
� No matter the time frame, these warning signs are often detectable by human senses― perhaps as much as 90 percent of the time, and three-quarters of these are detectable visually.
� Other breakdowns occur at predictable intervals of part age or use. What PMs might be put into place to catch the warning signs of this breakdown?
2. Why did our maintenance plan not prevent this
breakdown from occurring altogether?
� Did the part die earlier than its expected life because of
accelerated deterioration? If so, why are we not
maintaining the proper conditions-of-use for this part?
� Did the part reach its natural life expectancy? If the
breakdown was a true end-of-life breakdown, and the life breakdown was a true end-of-life breakdown, and the life
expectancy is predictable, a PM could be created to
replace the part when it is approaching the end of its
useful, but before it fails.
� Precision maintenance is 100 percent complete
maintenance carried out on time and executed precisely
according to the prescribed procedures. It is achieved
when “the machine does not know the difference” as to
who is performing the maintenance work.
� Maintenance must be carried out precisely to be
effective and to be effectively improved.
� Precision maintenance requires a great deal of � Precision maintenance requires a great deal of
preparation and support that most maintenance
departments lack. If precision is not achieved, further
improvements to the equipment maintenance plan will
not be effective.
Required detailed checklists� Creating and using a maintenance plan effectively
requires using detailed checklists to carry out scheduledmaintenance work.
� It also requires adhering in a disciplined way to checklist
criteria during PMs.This is different from allowing individual technicians to decide what any given PM should consist of and how it should be performed.should consist of and how it should be performed.
� Preventive maintenance routines not only must be
carried out with precision discipline, they also must be
improved continually. Creative improvements are best
captured each time that a PM is executed.
Transmission plant - Losses 2007
220
1.333892
5.961
4.613
2.828
1.416
689 687
0
1.000
2.000
3.000
4.000
5.000
6.000
NVA
AB
REA
KD
OW
NS
SCR
APS
DELTA
TM
SET-UP
STAR
T-UP/S
HU
T DO
WN
MIC
RO
STO
PPAG
ES
OVER
CO
NSU
MPTIO
N
UN
BA
LAN
CIN
G/D
ISSA
T.
K€/a
nn
oLink to cost deployment
BR
EAK
DO
WN
S
SCR
APS
DELTA
TM
SET-UP
STAR
T-UP/S
HU
T DO
WN
MIC
RO
STO
PPAG
ES
OVER
CO
NSU
MPTIO
N
UN
BA
LAN
CIN
G/D
ISSA
T.C matrix: K€ guasti / UTE
0
100
200
300
400
500
600
700
800
900
208 222 203 207 205 202 204 201 223 221
k€/a
nn
o
C matrix: breakdowns losses/ute
D matrix, fonte EWO:
imputazione guasti-pilastro di competenza
100
200
300
400
500
600
700
800
900
k€/a
nn
o
€/PD
€/FI
€/PM
€/AM
Losses stratification up to machine level
D matrixD matrixD matrix(EWO data source): breakdowns losses/pillar
PMPM
0
208 222 203 207 205 202 204 201 223 221
Ute 201 machine: breakdowns losses / PM pillar
0
10
20
30
210
170
200
130
180
K€
/ a
nn
o Ute 202 machines: breakdowns losses / PM pillar
0
5
10
20 100 120 10 50
K€ / a
nn
o Ute 203 machines: breakdowns losses / PM pillar
0
5
10
15
20
25
30
10 60 70 80 20
K€ / a
nno Ute 204 machines: breakdowns losses / PM pillar
0
10
20
30
40
50
60
70 110 100 30 120
K€ / a
nno
Ute 205 machines: breakdowns losses / PM pillar
0
5
10
15
20
110 150 120 130 50
K€ / a
nn
o
Ute 208 op: breakdown analisis / PM pillar
0
50
100
150
20 40 30 50 10
K€/a
nn
o
0
10
20
30
06.0
02.0 16
11
09.0 15
03.0 13
07.0 14
98
08.0 97
97carico
0.1
04.0
05.0 10
12
17
18
k€/a
nno
Machine level
D matrix(EWO data source):breakdowns losses / PM pillar
MODEL
AREA
AA
C matrix: K€ guasti / UTE
0
100
200
300
400
500
600
700
800
900
208 222 203 207 205 202 204 201 223 221
k€/a
nn
o
C matrix: breakdowns losses/ute
D matrixD matrix
Link to cost deployment
D matrix, fonte EWO:
imputazione guasti-pilastro di competenza
0
100
200
300
400
500
600
700
800
900
208 222 203 207 205 202 204 201 223 221
k€/a
nn
o
€/PD
€/FI
€/PM
€/AM
D matrix(EWO data source): breakdowns losses/pillar
PMPM
(4) Breakdown analysis to specify root cause(s)
-- Reactive : take countermeasures against the
recurrence of the same breakdown
-- Preventive : take countermeasures against
similar problems.
83
Revealing potential defects
Visible
breakdowns
Number of breakdowns does not decrease
84
Potential defects
Prevention of
breakdowns at the
similar process through
horizontal expansion Potential defects have been revealed
The importance of maintenance informationThe importance of maintenance information
A shop-floor where abnormalities can be detected
Skills “ Human ” sensor
Abnormality
in the effect
Operators who know
the equipment well
Detect
abnormalities
5 S
ZERO
・ Visual management
・ Fool proofPrevention
Image of ideal process Zero defects shop
in the effect
Abnormality
in causes
Flow Diagram for Preventing Recurrence of Unexpected
breakdownsUnexpected
breakdown
CMMS
Maintenance
department
Relevant workplace
Dealt with locally
NODaily/monthly
breakdown reports
Trouble input card
86
Restorative action Emergency action
Action to
restore operation
Emergency action Restorative action
YES
Maintenance
calendar
Machine history
ledger
Flow Diagram for Preventing Recurrence of Unexpected
breakdowns
Unexpected breakdown
report form
Prepare quick
breakdown report
CMMS
Section
responsible
Regular maintenance meeting
(investigate recurrence-
prevention measures)
Service input card
87
prevention measures)
Budget action
Instigate recurrence-
prevention measures
of the breakdown
Recurrence-
prevention
action report form
Prepare
action report
Filing
Equipment budget
appropriationYES
NO
Service input card
Instigate recurrence-prevention
measures of the similar breakdown
in other areas
(5) Easy C I LR
C : Eliminate contamination
I : Quick inspection
L : Central lubrication system
R : Refastening (marking, various methods not to
loose)
88
loose)
The Importance of CleaningThe Importance of CleaningThe Importance of CleaningThe Importance of Cleaning
Why clean ?Why clean ?Why clean ?Why clean ?
• Dust damages machines.Dust damages machines.Dust damages machines.Dust damages machines.
89
Detailed cleaning to remove all contamination ensures Detailed cleaning to remove all contamination ensures Detailed cleaning to remove all contamination ensures Detailed cleaning to remove all contamination ensures that all parts of equipment is touched. Only in this that all parts of equipment is touched. Only in this that all parts of equipment is touched. Only in this that all parts of equipment is touched. Only in this way can we find hidden defects.way can we find hidden defects.way can we find hidden defects.way can we find hidden defects.
Exposing seven types of abnormality
Abnormality Examples1.Minor Flaws
• Contamination
• Damage
• Play
• Slackness
• Abnormal phenomena
• Adhesion
Dust, dirt, powder, oil, grease, rust, paint
Cracking, crushing, deformation, chipping, bending
Shaking, failing out, titling, eccentricity, wear, distortion, corrosion
Belts, chains
Unusual noise, overheating, vibration, strange smells, discoloration, incorrect pressure
or current
Blocking, hardening, accumulation of debris, peeling, malfunction
2.Unfulfilled Basic 2.Unfulfilled Basic Conditions
• Lubrication
• Lubricant supply
• Oil level gauges
• Tightening
Insufficient, dirty, unidentified, unsuitable, or leaking lubricant
Dirty, damaged, or deformed lubricant inlets, faulty lubricant pipes
Dirty, damaged, leaking; no indication of correct level
Nuts and bolts: slackness, missing, cross-threaded, too long, crushed, corrected,
washer unsuitable, wing nuts on backward
3.Inaccessible Places
• Cleaning
• Checking
• Lubricating
• Tightening
• Operation
• Adjustment
Machine construction, covers, layout, foothold, space
Covers, construction, layout, instrument position and orientation, operating-range display
Position of lubricant inlet, construction, height, footholds, lubricant outlet, space
Covers, construction, layout, size, footholds, space
Machine layout; position of valves, switches, and levers; footholds
Position of pressure gauges, thermometers, flow meters, moisture gauges, vacuum gauges,etc.
Abnormality Examples4.Contamination Sources
• Product
• Raw materials
• Lubricants
• Gases
• Liquids
• Scrap
Leaks, spills, spurts, scatter, overflow
Leaks, spills, spurts, scatter, overflow
Leaking, spill, and seeping lubricating oils, hydraulic fluids, fuel oil, etc.
Leaking compressed air, gases, steam, vapors, exhaust fumes, etc.
Leaking, spilt and spurting cold water, hot water, half-finished products, cooling water,
waste water, etc.
Exposing seven types of abnormality
• Scrap
• Other
waste water, etc.
Flashes, cuttings, packaging materials, and nonconforming product
Contaminants brought in by people, fork-lift trucks, etc. and infiltrating through cracks
in building
5.Quality Defect Sources
• Foreign matter
• Shock
• Moisture
• Grain size
• Concentration
• Viscosity
Inclusion, infiltration, and entrainment of rust, chips, wire scraps, insects, etc.
Dropping, jolting, collision, vibration
Too much, too little, infiltration, defective elimination
Abnormalities in screens, centrifugal separators, compressed-air separators, etc.
Inadequate warming, heating, compounding, mixing, evaporation, stirring, etc.
Inadequate warming, heating, compounding, mixing, evaporation, stirring, etc
Abnormality Examples6.Unnecessary and Non-urgent
items
• Machinery
• Piping equipment
• Measuring instruments
• Electrical equipment
• Jigs and tools
• Spare parts
• Makeshift repairs
Pumps, fans, compressors, columns, tanks, etc.
Pipes, hoses, duct, valves, dampers, etc.
Temperatures, pressure gauges, vacuum gauges, ammeters, etc.
Wiring, piping, power lead, switches, plugs, etc.
General tools, cutting tools, jigs, molds, dies, frames, etc.
Standby equipment, spares, permanent stocks, auxiliary materials, etc.
Tape, string, wire, metal plates, etc.
Exposing seven types of abnormality
• Makeshift repairsTape, string, wire, metal plates, etc.
7.Unsafe places
• Floors
• Steps
• Lights
• Rotating machinery
• Lifting gear
• Other
Unevenness, tramps, projections, cracking, peeling, wear (steel deck plates)
Too steep, irregular, peeling anti-slip covering, corrosion, missing handrails
Dim, out of position, dirty or broken covers, not properly explosion-proofed
Displaces, fallen off or broken covers, no safety or emergency stop devices
Wires, hooks, brakes, and other parts of cranes and hoists
Special substance, solvents, toxic gases, insulating materials, danger signs protective clothing, etc.
Why inspect ?
• Inspection traces the conditions of areas known to be prone
to defect.
The Importance of InspectionThe Importance of InspectionThe Importance of InspectionThe Importance of Inspection
93
to defect.
• Inspection leads to understanding and ownership of what and
how to control conditions and make the job easy.
The Importance of LubricationThe Importance of LubricationThe Importance of LubricationThe Importance of Lubrication
Why lubricate ?Why lubricate ?Why lubricate ?Why lubricate ?
• Reduce friction and wearReduce friction and wearReduce friction and wearReduce friction and wear
• Dampen shockDampen shockDampen shockDampen shock
• Cool moving elementsCool moving elementsCool moving elementsCool moving elements
• Prevent corrosionPrevent corrosionPrevent corrosionPrevent corrosion
94
• Prevent corrosionPrevent corrosionPrevent corrosionPrevent corrosion
• Seal out dirtSeal out dirtSeal out dirtSeal out dirt
Poor lubrication destroys machines !Poor lubrication destroys machines !Poor lubrication destroys machines !Poor lubrication destroys machines !
Leaking oil, poor greasing, no lubrication regime creates Leaking oil, poor greasing, no lubrication regime creates Leaking oil, poor greasing, no lubrication regime creates Leaking oil, poor greasing, no lubrication regime creates
massively accelerated wear and tear.massively accelerated wear and tear.massively accelerated wear and tear.massively accelerated wear and tear.
Damage of bearings
Damages and Countermeasures
Wear on the outer rim
Condition of wear Cause Countermeasures
Wear occurred on the sliding
surface
(collar surface, roller surface or
pocket surface of a retainer)
Wear occurred on the rim or
rolling surface
Inappropriate or insufficient
lubrication oil
• Invasion of foreign body
• Review lubrication method or
lubrication oil
•Improve sealing devices
96
rolling surface• Invasion of foreign body
• Inappropriate of insufficient
lubrication oil
•Improve sealing devices
• Thoroughly clean around the
bearing
Damage of bearings
Damages and Countermeasures
Satin finished surface of the outer rim
Damage of bearings
Damages and Countermeasures
Satin finish surface of the inner rim
Condition of wear Cause Countermeasures
Impression like satin finish
surface occurred on the rim or
rolling surface
Main minute foreign body get in • Thoroughly wash around the
bearing
• Improve the sealing devices
and prevent foreign body from
99
and prevent foreign body from
invasion
Damages and countermeasures
Damage of toothed gears
Excessive Wear
Damages and countermeasures
Classification Phenomenon Cause
Deterioration of tooth
surface wear
Although wear does
not look serious from
outside, actually the
tooth surface is
chipped away
(1) In spite of the load
imposed on the tooth
and the roughness of
the tooth surface, oil
film is very thin. Thus chipped away film is very thin. Thus
the effect of
lubrication is almost
none, which causes
severe metal contact
repeatedly.
(2) The existence of
minute abrasive
foreign body may also
be the cause of the
wear.
Damages and countermeasures
Damage of toothed gears
Scratching
Damages and countermeasures
Classification Phenomenon Cause
Deterioration of tooth
surface : wear
Deep and linear
scratches appear
parallel to the sliding
direction of tooth
surface.
(1) Solid foreign body
with the diameter
bigger than the
thickness of the oil
film between two surface. film between two
tooth surfaces gets in.
(2) The surface of a
tooth is scratched
against its opposite
tooth surface with a
built in foreign body.
Damages and countermeasures
Damages of the chains
Insufficient oiling
Damages and countermeasures
Damages of the chains
Insufficient oiling
Damages and countermeasures
Symptoms/conditions
of damagesAnticipated cause Countermeasures
The wear takes place
at a part of the chain.
The chain is
elongated and thus
Insufficient oiling and
uneven oiling
condition
Periodically supply
the lubrication oil with
proper viscosity.
elongated and thus
that part does not
bend smoothly.
The pin with
lubrication oil is worn
out, and the one
without lubrication oil
shows adhesion wear.
Functional elementFunctional elementFunctional elementFunctional element Functional partFunctional partFunctional partFunctional part TroubleTroubleTroubleTrouble CauseCauseCauseCause
1. Lubrication Lubrication oil, grease Seize Lack of lubrication oil,
Improper oil
2. Bearing Ball, Roller, Plain bearing Seize, Vibration Lack of lubrication oil, Overload, Eccentricity
3. Body of rotation Impeller, Rotor Shaft seize, Vibration Unbalance
4. Connection Coupling, Gear, Key Breakage, Vibration Eccentricity, neglected wear
5. Transmission V belt, Chain, Clutch Sliding, Heat Neglected wear
6. Sealing Packing, Sealing Leakage, Explosion, Fire Neglected wear,
Functional elements and their troubles
6. Sealing Packing, Sealing mechanism
Leakage, Explosion, Fire Neglected wear, insufficient fastening
7. Dust protection Filter strainer Blocking Lack of cleaning, Damaged element
8. Fluid control Pipe, Valve, Orifice Abnormal pressure, Clogging, Abnormal quantity of flow, Leakage
Neglected foreign body
9. Fastening Bolt, Nut, Flange, Pin, Rotor
Vibration Insufficient fastening
10. Indication Pressure gauge, Instrument
Temperature, pressure, Abnormal quality of flow
Clogged, Insufficient checking
11. Main body Pump, Compressor Vibration, Leakage Damage, Insufficient fastening
108
109
Trouble due to
foreign matter, dust,
dirt, etc.
The floor must be
cleaned until no dirt
can be detected on
stroking with the palm
of the hand or a white
water-
soaked
mat
wat
er
Dust falling from
beams, crane hoists,
vent pipes, etc.
Splattering and
dropping of oil, water,
sweat
from
hands,
etc.
factory
110
of the hand or a white
glove er
tray
Dust and dirt brought in by
trolleys, movement of pallets,
packing materials and
machines, movement of
people, ingress of outside airScattering of sawdust, paper
fibers, etc.
Floor dust and dirt raised
by cleaning, movement of
people, and placing wire
slings, containers, etc. on
floor
Contamination brought in
on the work itself
Contamination created by
processing the work
dropping of oil, water,
dirt, etc.
etc.
Fig.
Countermeasures:
1. Wax or paint floors
2. Keep ceiling beams and cranes clean
3. Provide wet mats at entrances
4. Fit wheels with brushes or rags
5. Ensure that interior of workshop is not at
attach brush or ragbrush
111
5. Ensure that interior of workshop is not at
negative pressure
6. Do not install large-capacity ventilation
equipment unless absolutely necessary
grime collectorgrime collector
Fig. (Cont’d) Measures against sources of contamination in
precision machine shops
How to reduce time required for inspection
Transparent acrylic board
* Number of belts
* Wear, dust and dirt
* Tension
1. Make the hidden inspection spot
revealed.
2. Place the
112
*Vibra- tion*tempera- ture
2. Place the
inspection spot
at the height of
operator's eyes.
3. Make the
hidden parts
visible.
Easy to inspect
It takes too much time to inspect
113
time to inspect
strainer
strainer
Level 1 ( Checking by the check list )30 min.
Quick inspection
114
Level 2 ( Visual management ) 10 min.
115
Level 3 Concentration ( no need to walk ) 2 min.
116
Level 4 Easy recognition ( no need to have a check list )
30 sec.
117
Level 5 No need to check ( If something goes wrong, immediate alarm by light andsound )
Instantly
118
cf.:The four phases of establishing
the visual management system
There are too many lubrication spots.
Automatic lubricating system
To each lubrication spot
Central Lubrication
119
lubrication spot
Centralized oil charging
Two centralized lubrication systems which do not require
to stop the machine.
Distribution pipe
Carrier guide
120
Main pipe
Greasing pump
Distribution valve
Paper
Gear Timing belt
From gear driven mechanism
which requires lubrication To belt driven mechanism
which does not lubrication
Oil Charge-less
121
Automation for oil charging
Oil charge
by hand
Automatic
lubrication
Opera
tion s
ide
Drivi
ng
side
fra
me
Machine
Greasing bearings from outside
122
Opera
tion s
ide
fram
e
Drivi
ng
side
fra
me
* BearingGreasing thru cupper pipes
(6) Visual control
“In a world class plant, there is a system which
makes it possible to highlight any abnormality
123
visually in such a way that anybody can recognize
it as a problem.”
The necessity of
minimizing inspection
time
124
For reference
Non-loosened bolt!
Example: The overall check sections of an oil
lubrication system and check items;
joint pipe Distribution valve
Rotating section
Pressure control valvePump unit
①Oil leakage in the pipe or at the joint
distribution valve
②Crush and scratch on the pipe
①Oil leakage at the pipe connections
②Checking of discharged oil①Pulsation of the
pump
②Abnormal noise
of the motor
③Temperature of
the motor
<Check items of the
sliding section>
①Lack of oil film
②Damage of dust removal
wiper
①Pressure gauge
②Refastening of the
pipe connections
126
Lubrication oil
Oil tank①Checking of oil type
②Change of oil color
③Mixing of dust and alien obstacles
④Mixing of water
⑤Mixing of air bubbles
⑥Checking of viscosity
⑦Checking of oil temperature
①Oil level gauge
②Damage of tank
③Seal on the upper lid of the tank
④Oil inlet and oil charge filter
⑤Line filter
⑥Dust, dirt at the bottom of the inside of the tank
wiper
<Check items of the
rotating section>
①Lack of oil film
②Deterioration and
damage of the oil seal
③Wear metal
③Checking operation
of pressure control
valve
Checking methods and know-why (1)
Section
Checking items
Oil tank
(1) Check the level of
Upper limit
line
Lower
127
(1) Check the level of
the oil level gaugeLower
limit line
Checking methods and evaluation criteria
•By cleaning the oil level gauge, check if the oil level gauge is broken or not, if the
upper and lower limit lines have disappeared or not and if the oil level is appropriate or
not.
Improvement directions in the case of “no”
Know-why (Why is this improvement required?)
•Change the oil level gauge.
•Draw the upper and lower limit lines of the oil level gauge.
•Supply lubrication oil up to the upper limit line.
・Breakage of oil level gauge → Dust will be mixed in lubrication oil.
・Dirty oil level gauge, disappeared upper and lower limit lines
→Impossible to read the gauge
→Overflow takes place at the time of oil supply
→ Waste of oil
→ Make the machine and the floor dirty
128
→ Make the machine and the floor dirty
→Insufficient oil quantity
→Induction of air
→ Abnormal wear of the pump
→Lower air pressure
→Oil film of the lubrication required section being cut
→Unstable transfer of the processing point
→Defecting quality
→Lowered speed
→Stoppages by breakdown
→ Oil film of the lubrication required section being cut
Checking methods and know-why (2)
Section
Checking items
Oil tank
(4) Check the oil inlet
Oil filter
129
(4) Check the oil inlet
and the filter
Checking methods and evaluation criteria
•Remove the oil inlet cap and clean the inlet
•Check if there is oil filter installed
•Remove the oil filter and check if there is dirt, clogging or damage on the filter
•Check the mash of the filter
Improvement directions in the case of “no”
Know-why (Why is this improvement required?)
•Install the oil filter
•Clean the oil filter
•Exchange the oil filter with a new one
・Damage of the oil supply filter or no filter
→Invasion of dust and dirt
→Clogging of the suction filter element
→Occurrence of cavitations
→Unstable supply of oil to the lubrication required section
130
→Oil film of the lubrication required section being cut
→Abnormal wear of the lubrication required section
→Unstable transfer of the processing point
→Defecting quality
→Lowered speed
→Stoppages by breakdown
→Induction of dust and dirt
→ Abnormal wear of the pump and the valve
→Lower pressure
→Unstable oil supply to the lubrication required section
→ Abnormal wear of the lubrication required section
→ Forced deterioration of lubrication oil
Checking methods and know-why (3)
Section
Checking items
Oil tank
(5) Check dust and dirt
Rust, alien
substance
Rust, alien
substance
131
(5) Check dust and dirt
on the inner bottom of
the tankDirt, alien substance
Checking methods and evaluation criteria
•By putting a magnet bar from the oil inlet and checking the bottom of the tank
by the magnet, check if there is any metal or alien substance stuck to the tank.
Magnetic bar
Improvement directions in the case of “no”
Know-why (Why is this improvement required?)
•Wash the tank
•Apply the rust inhibitor, which does not influence oil, on the inside wall of the tank
•Remove the source of rust
・Deterioration of the seals on the upper board of the tank and/or the piping section.
・Clogging of the element in the air breezier
・Oil pot
・Abnormalities within the tank
132
・Abnormalities within the tank
→Alien metal substance (mainly rust)
→Occurrence of seizing in the pump, valve and lubrication required section
→Unstable transfer of the processing point
→Deterioration of quality
→Lowered speed
→Stoppages by breakdown
→Dust and dirt
→ Deterioration of lubrication oil
→ Clogging of the suction filter element
Visual Control to minimize inspection timeVisual control means that the equipment itself informs the
operator of its abnormality.
Abnormal !
133
The five requirements for the object of
visualization to make it work
1.Clear understanding of what function/operation it should
have
2.Its position
We must be able to see it easily and clearly (neither too high,
nor for low, nor too much in the depths.)
3.Its direction3.Its direction
(The object must show its face from the point where the
operator can see.)
4.What message it wants to convey exhibiting by quantifying
it as OK or not OK as much as possible.
5.Distinction by color so that the operator can see at a glance
by image without reading.
AirFilter
Regulator
Lubricator
AirFilterRegulator
Lubricator
The four phases of establishing the visual management system1.Phase 1
Identification of the object to be managed visually
Step 1 : arranging conditions in such a way that abnormality can be seen
(initial cleaning, etc. is just the starting point).
Comparison between Visual Indication and Visual Control
Visual
indication
Rubber
ring
Visual control
2.Phase 2
Visualization of the object to be managed
Step 2 : Visualization of potential defect
* It cannot be seen unless dismantled reveal it
Easy to Easy to inspect
It takes too much time to inspect
strainer
strainer
* It cannot be seen due to its position
Make it easy to Make it easy to Make it easy to Make it easy to tell whether the tell whether the tell whether the tell whether the thermocouple is thermocouple is thermocouple is thermocouple is fully insertedfully insertedfully insertedfully inserted
green (normal value)
red (safety limit)
137
Interior
Step 3 : Establishment of tentative standards to prevent abnormality to
take place.
3. Phase 3 Coloration of the object to be controlled
Step 4 : Destination between normal and abnormal
-- Basic conditions : no looseness, no oil deterioration
-- Processing conditions : right current, right voltage, no vibration,
accuracy of jigs, etc.
Step 5 : Coloration of the criteria, whether it is normal or not normal
Green : normal
Yellow : abnormal
Red : risky
Install in pumps, valves, bearings, motors, etc.
OK !
Washing
booth
[ Before ] [ After ]Water supply
display lamp
Scale
4. Phase 4 Leveling up the visual control system
Step 6 : Establishment of standards to prevent abnormality to take
place considering the above points of step 4, 5 on top of 3.
booth
CoverTank of washing
liquidFloat
• Paint defects due to shortage
of washing liquid
• Unnatural posture when to
inspect liquid level
• No scale on tank
• Noticeable in case of shortage
of washing water
• Safe inspection
• Early confirmation of
replenishment of washing liquid
• Automatic signal when
washing liquid is full
Step 7 : Enrich visual control of the system
-- long life
-- intensive
-- simplified
-- from visual control to non visual control which does
not require watching
Level 5 No need to check
( If something goes wrong, immediate alarm by light and sound)
Instantly
Three key words for visualization
1.Easiness of watching
* Make the face of the object visual
* Make it visible
* Requires no labor nor time
2.Pursuit of easy understanding
* Quantify normal and abnormal conditions
* Make easy to see it
* Make easy to understand and judge by image* Make easy to understand and judge by image
3.Conspicuousness
* Attract attention
* Make it non-ordinary
* Make it striking
The flower
withers when oil
has been run out
When a right amount
of oil is fed, the
flower becomes
open by the move-
ment of the float.By looking at the
flower, we can
observe anomaly
of the oil quantity
The buoyancy of
the float
The three major effects we can expect by visualization
1.Timing : Early discovery of abnormality
(Prevention of possible losses/happenings of
troubles)
2.Accuracy : Prevention of forgetfulness, lack of attention, 2.Accuracy : Prevention of forgetfulness, lack of attention,
wrong judgment, wrong action)
3. Pace : Quick and efficient checking and inspection
When some part, if it breaks, has a
risk of creating a huge damage, then
it must be placed to expose it to
human eyes such that its anomaly
can be detected quickly enough
143
can be detected quickly enough
even if such placement looks ugly.
(eg. The rupture of hoses,
breakdowns of cables)
144Shop floor is a mirror.
Visualization for the checking route
145
(7) From BM, TBM (AM & PM calendars) to the intelligent
maintenance (combination of BM, TBM and CBM)
146
6.The aims of Autonomous Maintenance
and Professional Maintenance
Mancato
mantenimento delle
condizioni base
Mancata osservanza
delle condizioni Mancato ripristino
delle anomalie
Progettazione della
macchina e/o dei
Scarse competenze
degli operatori e dei
manutentori
Influenze esterne
Materiali, Ricambi,
Clima, ecc
147
condizioni baseoperativedelle anomaliemacchina e/o dei
componenti debolemanutentoriClima, ecc
Segnalazione al
costruttore,
fornitore
OPL per operatori
e manutentori
Matrice delle
competenze
Standard di
progettazione
Calendario PM
OPL sulle
condizioni
operative
Definire gli
standard di AM
Definire gli
standard di AM
1. To prevent equipment deterioration through correct
operation and daily checks
2. To bring equipment to its ideal state through
restoration and proper management
Aims of AM (Autonomous Maintenance)Aims of AM (Autonomous Maintenance)Aims of AM (Autonomous Maintenance)Aims of AM (Autonomous Maintenance)
148
restoration and proper management
3. To establish the basic conditions needed to keep
equipment well-maintained
� A machine breakdown does not occur suddenly.
There is a symptom of the breakdown before it takes
place. That is, it is the result of the growth of a minor
defect.
� To eliminate breakdowns, it is necessary to check
equipment for detecting a symptom of a breakdown.
The roles of autonomous maintenance
149
1
equipment for detecting a symptom of a breakdown.
� Maintenance crew cannot detect and cover all the
symptoms of breakdown.
� It is the operators of machines and processes who
can catch the information on the status quo of an item
of plant and prevent it from breaking down.
� Unless the operators know how to maintain equipment,
they cannot help having equipment breakdowns.
� AM is powerful in case where there are operators and
where breakdowns, defectives and minor stoppages
take place due to lack of maintaining the basic
condition of equipment and when they inspect their
equipment.
150
1
Easy to inspect
It takes too much time to inspect
strainer
strainer
1200
1000
800
( No. of breakdowns )
The basic rules for reducing breakdowns to
zero are countermeasures based on the
identification of hidden breakdowns and
autonomous maintenance by production
department. Tokai Rubber carried out these
measures and was able to significantly
reduce breakdowns in just over 2 years. In
Trends in reduction of equipment breakdown
600
400
20
0
0
1 4 6 7 8 9 10 11 122 3 5 1 4 6 7 8 9 10 11 122 3 5 ・ ・ ・ ・ ・
( month )
Phase
1
Phase 2 Phase 3 Phase 4
reduce breakdowns in just over 2 years. In
some factories they achieved zero
breakdowns.
1. To maximize equipment reliability and
availability at an economical cost
2. To eliminate unplanned maintenance
activities
Aims of PM (Preventive Maintenance)
152
3. To achieve zero breakdowns and process
breakdown losses with the cooperation of
production people (AM) and quality people
(QC).
Tota
l num
ber
of bre
akdow
ns PM
PM(AM)
Including
Human
errors
• In general, one third of breakdown
comes from lack of basic conditions.
• Another one third of them can be
avoided if the competence of AM
people can be raised and AM step 1
– step 7 are carried out rigorously
153
Tota
l num
ber
of bre
akdow
ns
PM(AM)
Lack of the basic
conditions
– step 7 are carried out rigorously
with well organized inspection of
natural deterioration, but this costs
much money.
• The rest can be tackled by PM step 1
– step 3. Once we establish a PM
calendar, we understand what we have
to do with the equipment.
Example
6000
5000
4000
( Incidents / months )
Natural
deterioration
of inside
Natural
deterioration
of outside
Forced
Number of breakdown
Transition of the number of
breakdowns at “ D company ”
Factory figures:
1. Maximum production capacity:
32,000~35,000 units per month
2. Employees3000
2000
1000
02nd half
1st year
1st half
3rd year
1st half
2nd year
1st half 2nd half
Forced
deterioration2. Employees
3,200 people
3. Number of equipment
4,000 units
4. Production processes
1st division: Machining, adjustment,
pressing, plating
2nd division: Plating, coating,
assembly
Divisions of functions between operational and maintenance departmentsDivisions of functions between operational and maintenance departments
AimType of
method
Activities carried out
Prevent
deterioration
Measure
deterioration
Restore
deteriorated part
Categorization
Oper
ation
Mainte
nance
opera
tion o
ver
Proper operation
Scheduling / Adjustment
Cleaning, identification of hidden defects, response
Lubrication
Tightening
Conditions of use, daily inspection for deterioration
Ma
inte
nan
ce
activitie
sNormal
operation
Daily
maintenance
Regular
Minor maintenance
Regular inspection
Regular check
◎◎◎◎◎◎◎○ ◎
◎
Effic
iency o
f
facili
ty
opera
tion o
ver
85%
Improvement
maintenance
Maintenance and
improvement
Improve strength
Reduce load
Improve precision
Imp
rove
me
nt
activitie
s
maintenance
Advance
maintenance
Follow-up
maintenance
Reliability
Maintainability
Regular maintenance
Test tendencies
(assessment technology)
Irregular maintenance
Early discovery and confirmation of
circumstances, rapid response
Sudden, irregular repairs
Condition monitoring
Improve inspection procedures
Improve maintenance
operations
Improve quality of equipment
○
◎
○◎○◎
◎◎◎◎
◎◎○◎○◎◎◎
Step 7
Fully implemented autonomous management
Step 3
Step 4
Step 5
Step 6
Equipment inspection for quality
General process inspection
Self-workplace management
Challenge this step
and find benefits.
(for Production People : capital intensive
area)
7 steps of Autonomous Maintenance
156
Initial cleaning
Step 1
Step 2
Countermeasures against sources
Tentative standards
Reactive Preventive Proactive
Promote Autonomous Maintenance Step by Step
Step Step Step Step ActivitiesActivitiesActivitiesActivities
1. Perform Initial cleaning
• Eliminate dust ant dirt from main body of equipment• Expose irregularities such as slight defects, contamination sources, inaccessible places, and sources of quality defects
• Eliminate unnecessary and seldom-used items, and simplify equipment
2. Address contamination sources and inaccessible places
• Reduce housekeeping time by eliminating sources of dust and dirt, preventing scatter, and improving parts that are hard to clean, check, lubricate, tighten, or manipulate
157
inaccessible places
3. Establish leaning and checking standards
• Formulate work standards that help maintain cleaning, lubricating, and tightening levels within minimal time and effort
• Improve the efficiency of checking work introducing visual controls
4. Conduct general equipment inspection
• Achieve quality maintenance and safety by establishing clear procedures and standards for dependable autonomous maintenance
• Provide inspection skills training based on inspection manuals• Get individual equipment items into peak condition by subjecting them to general inspection
• Modify equipment to facilitate checking.• Make extensive use of visual controls
Promote Autonomous Maintenance Step by Step
Step Step Step Step ActivitiesActivitiesActivitiesActivities
5. Perform general process inspection
• Provide instruction in process performance, operation, and adjustment and in methods of handing abnormalities in order to improve operational reliability by developing process-competent operators
• Prevent inspection duplications and omissions by incorporating provisional cleaning and inspection standards for individual equipment items into periodic inspection and replacement standards for entire processes or areas
158
6. Systematize autonomous maintenance
• Improve setup procedures and reduce work-in-process• Establish a system of self-management for work place flow, spares, tools, work-in-process, final products, data, etc.
7. Practice full self-management
• Evolve activities and standardize improvements in line with company and plant policies and objectives, and reduce costs by eliminating work place waste
• Improve equipment further by keeping accurate maintenance records (e.g., MTBF) and analyzing the data in them
Four steps to capable operatorsFour steps to capable operatorsFour steps to capable operatorsFour steps to capable operators
Practice full autonomous management
Production based on the given schedule (focus : production)
Achieving zero breakdowns and zero defects with the help of PM and QC people. Responsible for daily production
Self workplace management
Workplace flow Detects process abnormalities
7777 4444
159
management (focus : process) promptly; takes emergency action against them
Perform general process inspection
Process problems
(focus : process)
Machine capability
(focus : machine)
Achieve quality maintenance and safety by establishing clear procedures and standards for dependable autonomous maintenance
Equipment inspection
for quality
Establish cleaning and checking standards
Basic conditions to prevent deterioration (focus : machine)
Understands process performance and functions; operates process correctly
Address contamination sources and inaccessible places
Perform initial cleaning1111
2222
3333
4444
5555
6666
1111
2222
3333
Five Levels of Operators
Operation only
Multi-operations
Operation only
Multi-operations
160
2 + QC + AM
3 + Improvement
4 + Engineering
2 + QC + AM
3 + Improvement
4 + Engineering
Autonomous maintenance
� When equipment does not have the basic condition to be operated
and there are many possible causes which may lead to breakdowns,
a collective approach by AM without persistently asking why, why, - -
- to identify root causes, can work well. But when there are few
breakdowns, AM can be very costly.
� Step 2 is key to get the benefits of AM.
� Applying AM Step 1 – 3 is the key to establish the basic condition
161
� Applying AM Step 1 – 3 is the key to establish the basic condition
of the equipment.
� The major economic benefit of AM can be gained by AM Step 1 – 3.
� Step 4 costs time and money.
� Depending on the breakdown situation of the equipment applying
Step 4 cannot be economically justified.
� We need to add something extra activities on Step 4 to get benefits
out of it.
More Details in Pillar Approach for Better and Continuous Results in Processes Under Control
Step 1 Non quality
REORGANIZATION
WORKING STATION
Period from 2007 to 2009 with focus
on M-machine losses
Since 2009 focus on other M
Man + Method + Material
162
AM workshop
model
Step 2
Step 3
Breakdown
cause initial
conditions
Start-up CHANGE TYPE
OTHER LOSSESW
Minor
stoppagesStep 4
Step 5 CHANGE TOOL
Step 6
� Deploy cross-departmental teams, ideally
involving everyone in the organization, to
all machines on the factory floor, one
team per machine or line.
� Train each team member to competently
use WCM AM tools and productivity use WCM AM tools and productivity
improvement methods.
�Charter each team to attack the
productivity losses on their equipment―
first preventing machine breakdowns, and
then reducing other types of losses.
Install in pumps, valves, bearings, motors, etc.
� Challenge these teams to achieve a rapid
improvement rate, typically a minimum of
50 percent improvement within a year.
Specific machine losses should be
reduced to zero.
�Deliver contingent consequences to team
Install in pumps, valves, bearings, motors, etc.
�Deliver contingent consequences to team
members for their contribution to
successful results: greatly reward the
highest level contributors, and help others
to improve their level of contribution.
motors, etc.
Employees are intelligent individuals
who are motivated by work that keeps
them informed about how their efforts
affect the outcome and gives them affect the outcome and gives them
power and responsibility to reach their
goals.
1. To maximize equipment reliability and availability at
an economical cost
2. To eliminate unplanned maintenance activities
3. To achieve zero breakdowns and process
Aims of PM (Preventive Maintenance)
166
3. To achieve zero breakdowns and process
breakdown losses with the cooperation of production
people (AM) and quality people(QC).
Step 7
Build a predic-
tive mainte-
nance system
(trend
management)
Maintenance
cost
management
Establishmen
t of
a planned
maintenance
system
Build a
periodic
maintenance
systemPhase 1
Phase 2
Phase 3
Phase 4
Step 3
Step 4
Step 5
Step 6
Countermeasures
against weak
7 steps of Professional Maintenance
167
Elimination of forced deterioration
and prevention of accelerated deterioration
Reverse
deterioration
(breakdown analysis)Step 1
Step 2
Step 3
Establishment
of
maintenance
standards
against weak
points
of the machine and
lengthened equip-
ment life
Reactive Preventive Proactive
Applying PM Step 1 – 3 with rigor is the
key to eliminate breakdowns. The rest is
the refining PM activities.
Individual product life
Faults occur
in this range
Only this range
Exchange cycle 1
Increase strength
(Improvement)
Exchange cycle 1
Exchange cycle 1
Exchange cycle 2
An approach to achieving zeroAn approach to achieving zero--breakdown operationbreakdown operation
Phase 1
Reduce variation in time
between breakdown
Phase 2
Increase average
remaining life
Phase 3
Regularly restore
deterioration
Phase 4
Predict breakdown
Only this range
does not failExchange cycle 2 Exchange cycle 2
Exchange cycle 3
Regular
maintenance
Exchange cycle 3
Irregular replacement from prediction of
remaining life
Restoring deterioration of parts
which have been left unattended
・Dealing with hidden faults
Eliminate forced deterioration
・Establish basic conditions
・Preserve order for operation
conditions
Extending individual product life
・Improve weak points regarding
individual product life
・Improve weak points regarding
overloading
・Select parts appropriate to the
situation
Eliminate random breakdown
・Dealing with operational errors
(Think of failsafe devices)
・Dealing with repair errors
(Improve procedures, tools)
Restore external deterioration
・Repair all deterioration in external
appearance
Estimation of product life and
regular restoration of
deterioration
・Improve maintenance (Increase
efficiency)
Use the five senses to grasp
signs
Indicating internal deterioration
・Distinguish faults which show
signs of damage from those
which don’t
・Investigate how to recognize
early signs
・Operator education
Predict faults through
technological and assessment
skill
・Methods of reducing maintenance
costs
Estimate and lengthen remaining
life through technical analysis of
faults due to physical damage
・Technical analysis of cause
Fractured cross section, material
fatigue, concentrated stress
Phase 1 ( Reduce the number of breakdowns to half) Phase 1 ( Reduce the number of breakdowns to half) ― Step 1 to Step 2― Step 1 to Step 2
Stabilize the interval between one breakdown and the next one
① Restore deterioration which has been left unattended
Priority must be given to addressing defects which are apparent but are not
attended due to either a tight budget or the lack of motivation.
・ Being left in use.
・ Being left loose
・ Being left out of position
・ Being left out of order
Make a list → Take countermeasure
Being left out of order
② Eliminate forced deterioration
Abnormal deterioration caused by excessive stress above the designed
level → Forced deterioration
(1) Maintain basic conditions – cleaning, lubricating, retightening
(2) Comply with conditions of use
・ Prevention against external disturbances, such as vibration, noises, etc.
・ Conditions appropriate for the specification of a unit of part
environmental conditions, appropriate load, method of attachment
・ Loading conditions appropriate for the equipment’s capability
Phase 2 ( Reduce the number of breakdown 1/5)Phase 2 ( Reduce the number of breakdown 1/5)
Lengthen equipment lifespan
① Lengthen part lifespan
Where remaining life is short even where forced deterioration is excluded, an
analysis of weak points can help prolong life
(1) Improve design weaknesses
・ Lack of strength
・ imperfections in installation.
・ imperfections in processing
(2) Improve weaknesses against overloading
If the amount of load on the equipment cannot be reduced, strengthen
(3) Select components appropriate for the conditions of use
If the amount of load on the equipment cannot be reduced, strengthen
the weakest point
② Eliminate chance breakdowns
(1) Countermeasures against repair misses ・ Acquire basic repair skills
・ Improve repair methods, etc.
(2) Countermeasures against human errors ・ Standardize methods of operation
・ Attaching fool proof device, failsafe
device, etc.③ Restore external deterioration
General external inspection of hydraulic and pneumatic units, driving systems,
electrical systems, etc. and restoration of deterioration
Phase 3 ( Reduce the number of breakdown 1/10)Phase 3 ( Reduce the number of breakdown 1/10)
Periodic restoration of deteriorated parts
① Estimating MTBF and periodic restoration of deterioration
The first and second phases will extend MTBF and stabilize MTBF.
Therefore, the validity of periodic restoration will increase from the viewpoints of
reliability and cost.
(1) Improve maintainability
Add structural improvements to
equipment easier to maintain
・ Use common parts
・ Exchange blocks
・ Simplify assembly and disassembly
(2) Standardization and execution of
periodic maintenance
・ Periodic inspection
・ Periodic checks
・ Periodic servicing・ Simplify assembly and disassembly
・ Improve jigs and tools and make them specialized
・ Standardize spare parts
② Use five senses to grasp abnormalities indicating deterioration
If you have difficulty in determining the remaining life, or cannot eliminate a wide
variation of the part lifespan, the only method is to detect early sign of breakdowns
1) Before the breakdown occurred, were there any symptoms of any abnormalities?
2) Does this breakdown produce any early warning signs or not?
3) What early symptoms can lead to the discovery of this breakdown?
4) Why were we unable to detect the early symptoms of this breakdown?
5) What can we do to detect the early symptoms of the breakdown?
6) What knowledge and skills are necessary for the operator or notice the symptoms
of the breakdown?
Phase 4 ( Reducing the number of breakdowns to zero)Phase 4 ( Reducing the number of breakdowns to zero)
Predict and extend equipment life times
①Prediction of breakdowns by applying equipment diagnoses techniques.
Deterioration pattern:・Leaks
・Breakages・Corrosion・Abnormal sounds・Abnormal temperature・Abnormal vibration・Material degradation
Measurement tool:・Shock pulse meter・Vibration measurement・Measurement by ultrasonic sounds (AE method)・Magnetic, X ray search・Spectrographic analysis (SOAP method)・Insulation measurement
②Catastrophic breakdown – Estimation and lengthening of the remaining life
using technical analysis
・Oil degradation・Looseness・Abnormalities in the electrical system
(1) Analysis of a fractured cross section
Concentrated stress
(2) Analysis of material fatigue
Repetitive load
Alternating load NSN curve analysis
(3) Analysis of the gear tooth surface
0,02
0,04
0,06
0,08
0,10
0,12
Substitution is planned at the
beginning of wear
MTBF = 2040 h
σ = 195 h
MTBF = 870h
σ = 500h
PM METHODOLOGYPhase 1 Stabilize MTBF
-
Wear
zone
Every 1650hλ
0
100
200
300
400
500
600
700
800
Ciabat
ta T
urck
Stafff
a V
ep
Mic
ro 3
2M
otore
pin
zaporta
elettr
odi av
atto
seg
nali
colla
rino
blocc
aggio
forc
ole
flangia
fresaMaint. Cost= Cmanhours + Cspare parts
Maintenance costs
Components Pareto
PM METHODOLOGY Phase 2 - Lengthen components life
Ciabat
ta T
urck
Stafff
a V
ep
Mic
ro 3
2M
otore
pin
zaporta
elettr
odi av
atto
seg
nali
colla
rino
blocc
aggio
SOLLECITAZIONE AMMESSA A PROGETTO
SOLLECITAZIONE DI LAVORO
PROBABILITA
SOLLECITAZIONE
AMMESSA A
PROGETTO
Safety
Threshold
Lengthen the component life
PM METHODOLOGY Phase 2 - Lengthen components life
Material of
The bush not enough resistent
created an exchangeble steel bush installed by a
ring on the previous component
Solution Extended
on 132 Guns in Body
Made in one piece
Designed with
the supplier
PM METHODOLOGY Phase 3 Phase 3 –– Periodically restore deteriorationPeriodically restore deterioration
Substitution
on condition
DESIGN SPECIFICATION:
The thickness of the self-lubricating bush is
the parameter to be monitored in order to
optimise the component life
t nom. = 1.3mm
t min = 0.3mm0,2
0,4
0,6
0,8
1
1,2
1,4
Substitution
by time
Maintenance Planning
0
0,2
PLANNING P.M. REVISION
177
Implementation
PlanCountermeasure
defined
Root Cause
Defined
FREQUENCY CYCLE FREQUENCY CYCLE
MODIFIEDMODIFIED
TYPE OF MAINTENANCE TBM, CBM, BM, ELECTRICAL,
MECHANICAL, ETC..
LAY-OUT
CYCLE DESCRIPTION
FRECUENCY TIME
COMPONETS UNDER THIS CYCLE
RESPONSIBLE TO MAKE THIS
CYCLEWHERE
178
INTERVENTIONS POINTS
PM METHODOLOGY Summary
Wear-out and corrosionlead to failures�
Because of deterioration, breakdownsoften take place
Basic conditions
�The progress of deterioration is relatively
Machine MTBF~3000h
�The period between two consecutive breakdowns is relatively long
Electronic components
Gear boxes�Breakdowns cannot be prevented by a normal inspection and servicing
TBM cannot cover unexpected failures�
Sporadic breakdowns often take place
Major Breakdowns
MTTR>=1,5h�When a breakdown takes place, it willinfluence production output substantially
Wear-out and corrosionlead to failures�
Because of deterioration, breakdownsoften take place
Basic conditions
�The progress of deterioration is relatively
Machine MTBF~3000h
�The period between two consecutive breakdowns is relatively long
Electronic components
Gear boxes�Breakdowns cannot be prevented by a normal inspection and servicing
TBM cannot cover unexpected failures�
Sporadic breakdowns often take place
Major Breakdowns
MTTR>=1,5h�When a breakdown takes place, it willinfluence production output substantially
1) ITEMS TO CHOOSE CBM FROM PAST EXPERIENCE
OVERMAINTENANCE AND SERIOUS breakdownS DATA
2)COMPONENT EVALUATION:
-DETERIORATION PATTERN
-CONTROL PARAMETERS
PM METHODOLOGY Phase 4 - CBM
Basic conditionsmainteined by AM�
The progress of deterioration is relativelyslow
Basic conditionsmainteined by AM�
The progress of deterioration is relativelyslow
COMPONENTE PARAMETRO STRUMENTO IMPATTO MODALITA'
TEMPERATURA TERMOCAMERA AFFIDABILITA'ANALISI TERMOGRAFICA DURANTE
CICLO DI LAVORO
ECCENTRICITA' ACCELEROMETRO AFFIDABILITA'MISURA DELLO SPOSTAMENTO MEDIO
PER INTEGRAZIONI SUCCESSIVE
RESISTENZA
ELETTRICA
ISOLAMENTO
TESTER AFFIDABILITA'
SICUREZZA
VERIFICA DELL'ISOLAMENTO
ELETTRICO TRA LE FASI DEL MOTORE
VIBRAZIONE ACCELEROMETRO AFFIDABILITA'ANALISI IN FREQUENZA DELLE
AMPIEZZE DI VIBRAZIONE
GIOCO COMPARATORE
1/100 [MM]
QUALITA'
AFFIDABILITA'
CEDIMENTO DINAMOMETRO
25 [KG] FS
SICUREZZA
CUSCINETTI DEFORMAZIONE ACCELEROMETRO AFFIDABILITA'MISURA DELLO SPOSTAMENTO MEDIO
PER INTEGRAZIONI SUCCESSIVE
ASSORBIMENTO
CORRENTE
SOFTWARE DI
DIAGNOSTICAAFFIDABILITA'
ACQUISIZIONE DATI ASSORBIMENTO
TRAMITE PROGRAMMA
TEMPERATURA TERMOCAMERAAFFIDABILITA'
SICUREZZA
ANALISI TERMOGRAFICA DURANTE
CICLO DI LAVORO
VENTOLE DI
RAFFREDDAMENTO
VELOCITA' DI
ROTAZIONE STROBOSCOPIO AFFIDABILITA'
COMPARAZIONE CON FREQUENZA
DELLA LAMPADA
MISURA DIRETTA AD ESTREMITA'
LIBERA DELL'ASSE
AZIONAMENTI
MOTORE
ELETTRICO
RIDUTTORI
4) TRAINING FOR
DIAGNOSTICIAN
PURCHASING OF
DEVICES
3) DIAGNOSIS EQUIPMENT AND
METHODS SELECTION5)PARAMETER
MEASURING AND
TREND MANAGEMENT
PM METHODOLOGY Paint Shop - Vibration Analysis on Exhaust Air Fans
MAINTENANCE COST OF EXHAUST AIR FANS AT STEP 3
€ 32.700
€ 14.331
€ 4.800€ 1.800 € 975 € 450 € 300 € 75
€ -
€ 5.000
€ 10.000
€ 15.000
€ 20.000
€ 25.000
€ 30.000
€ 35.000
ROTOR BEARINGS BELT MOTOR BEARINGS SPRING PULLEY SHAFT
EU
RO
/YE
AR
ROTOR BEARINGS BELT MOTOR BEARINGS
SUPP.
SPRING PULLEY SHAFT
B\C = 8.1
PM METHODOLOGY Phase 4 – Trend Management in Body Shop
Andamento misure di Pressione Pinza
-12%
-10%
-8%
-6%
-4%
-2%
0%
2%
4%
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55
misure
soglia
Lineare (misure)
Real time management and
control Welding Gun
Pressure
WE COVER 234 COMPONENTS IN OP20A WITH:
• 5 CBM CYCLES
• 4 TBM CYCLES
AND WE COVER 258 COMPONENTS IN LACAS2 WITH:
• 2 CBM CYCLES
• 4 TBM CYCLES
183
• 4 TBM CYCLES
WHICH CONTAIN THOSE COMPONENTS.
7 steps to parts development7 steps to parts development
Phase Proce
dure
Name Details of activities
1
Reduce
variation in
remaining life
1
Analysis difference
between designated
usage conditions and
current conditions
Select important equipment, establish all current causes of faults, and use
analysis to plan measures to achieve correct usage conditions, and
restore visible deterioration in the equipment.
2 Measures for dealing
with difference in 1.1
Improve problem points were usage conditions are not being met, and
increase the reliability of the equipment
3
Create standards for
usage conditions
Set provisional standards, and execute them, work towards improvement
Set standards for cleaning, lubrication, tightening.
Clarify division of maintenance responsibilities among departments.
2 Measures for dealing Define and improve conditions of use2
Increase
remaining life
for individual
units
4
Measures for dealing
with problems in
lengthening remaining
life (Improve
maintenance)
Define and improve conditions of use
Increase remaining life through improvement and maintenance
Eliminate random faults caused by mistakes in operation and repair
Form and execute plans based on loss analysis.
3
Restore
regular
deterioration
5
Improve efficiency of
checking
Ready maintenance standards, aim to improve maintainability, ease of
operation and safety.
Find abnormal signs indicating deterioration, and execute measures to
deal with weak points in the inspection.
4
Predict
remaining life
6
Overall assessment
of equipment (MQ
analysis)
Establish maintenance procedures which emphasis product quality, based
on assessment of equipment faults and MQ analysis.
(Clarify the relationship between the equipment and product quality, and
guarantee reliability of product quality through PM)
7
Establish limits of use Determine limit points of faulty equipment and establish plans for the use
of assessment technology.
Technical analysis of critical faults.
Step 4
Step 5
Step 6
Step 7
Establishment
of a periodic
MQ analysis,
trend management
and checking
Component
cost
management
Phase 1
Phase 2
Phase 3
Phase 47. Component Maintenance
185
Step 1
Step 2
Step 3
Step 4
Investigation of gaps between
designated usage conditions and
current conditions of use
Countermeasures
against the gaps
Establishment
of maintenance
standards
Measures to
extend
component life
of a periodic
replacement
cycle
Phase 1
Phase Step Title Objectives
1
Stabilize mean time between breakdowns ( MTBF )
1 Investigation of gaps between designated usage conditions and current conditions of use
・ Selection of important components.
・ Restoration of the apparently deteriorated parts.
・ Clarification of designated usage conditions.
・ Investigation of gaps between designated usage conditions and current conditions of use.
2 Countermeasures against the gaps
・ Elimination of the gaps and improvement of the reliability of the equipment.
3 Establishment of maintenance standards
・ Setting tentative maintenance standards, especially for cleaning , lubricating and retightening.
・ Clarification of roles of maintenance for production and maintenance.
2
Lengthen
4 Measures to extend component life
・ Definition and improvement of conditions of use.
・ Extension of the lifetime by corrective maintenance.
7 S
teps o
f P
rofe
ssio
nal M
ain
tenance (
com
ponent le
ve
l)
Seven steps of establishing professional maintenance ( component level )
186
Lengthen component’s
life
component life ・ Extension of the lifetime by corrective maintenance.
・ Elimination of chance breakdowns caused by human errors and repair errors.
3
Periodically restore deterioration
5 Establishment of a periodic replacement cycle and improvement of inspection efficiency
・ Setting maintenance standards and improvement of maintanability, operationability, and safety.
・ Investigation of abnormal symptoms indicating deterioration.
・ Execution of countermeasures against weak points in carrying out inspection.
4
Predict component’s
life
6 MQ analysis, trend management and checking
・ Establishment of CBM and Quality maintenance by MQ analysis.
・ Clarifications of the relationships between the equipment and the product quality, and maintenance of product quality by PM.
7 Component cost management ・ Determination of the limit point of the component.
・ Technical analysis of catastrophic breakdowns.
・ Utilization of equipment diagnosis techniques.
7 S
teps o
f P
rofe
ssio
nal M
ain
tenance (
com
ponent le
ve
l)
Red cards
PM cards
―― ――
Development of professional maintenance (component level)
Focused Improvement Daily measures Deployment by part (1st ~ 4th step)
Focus on time
Focus on the possibility
of producing a massive
volume of detectives
Pe
rso
nn
el i
n c
ha
rge
Serious breakdowns
Important equipment
Reply1st step
2nd step
3rd step
Focus on frequency
Focus on the number of
breakdown
Study the focused
breakdown for the
Check all
the reports
How to deal with PM
cards
Information on autonomous
maintenance
187
Pe
rso
nn
el i
n c
ha
rge
List of horizontal expansion
Checklist of other machines
Continued themes
and
Countermeasure
themes
Spare parts management Standardization Assistance to autonomous maintenance
7th step Full utilization of equipment
6th step MQ maintenance
(Equipment Diagnosis)
5th step Efficient inspection
4th step Measures to extend the lifetime
breakdown for the
day
Through recording
cards maintenance
Pareto diagram of broken components (example)
188
Cause classification of bearing breakdowns
Number of
breakdowns
Outflow of grease 3
Excessive tightening of distribution valve 3
Loosened copper pipe 2
Carbonized grease 2
Defective distribution valve 1
Leakage from pipe flange 1
Insufficient grease change at the installation stage 1
Classification
189
A A A A BBBB DDDD
2 4 1 3 5 1 5 3 4 2 2 1 5 3 4 6
1
2
3
4
5
6
Type of
equipment
Name of
componentC
om
mon c
om
ponent
Number of
breakdowns
190
10
Com
mon c
om
ponent
Model components
Model equipment
Nu
mb
er
of
bre
akd
ow
ns
Model equipment? Model components?
LowLowLowLowInterInterInterIntermedimedimedimediateateateate
HighHighHighHighLowLowLowLowInterInterInterIntermedimedimedimediateateateate
HighHighHighHighFewFewFewFewMediMediMediMedi----umumumum
ManyManyManyManySMBFewFewFewFewMediMediMediMedi----umumumum
ManyManyManyMany
Autonomous
Mainte-
Nance Level
Maintenance skills
Number of maintenance people
Forced
deterioration
Number of machines
Model machine? Model component?
191
Parts
ateateateateateateateate----umumumum----umumumum
Equip-
ment
Appendix: OEE calculation
192
Cost deployment identifies 18 big losses at the beginning:
Equipment : 10 major losses
(i) 7 major losses obstructing overall equipment effectiveness
1) Equipment downtime loss
(1) Equipment breakdown loss
Sudden and unexpected equipment breakdowns or breakdowns, Sudden and unexpected equipment breakdowns or breakdowns,
are an obvious cause of loss, since an equipment breakdown
means, that the machine is not producing any output.
(2) Changeover loss
A changeover is determined by a planned variation in the
production plan or replacing tools / dies due to wear and tear or
being broken.
(4) Cutting blade change loss
(3) Set-up & adjustment loss
Most machine changeovers require some period of shutdown so
that internal components can be exchanged or adjusted. The
time between the end of the last good product produced and the
first good product produced of the following production run is
downtime. This downtime loss often includes substantial time
spent making adjustments until the machine gives acceptable
quality on the required product.
(4) Cutting blade change loss
(5) Start-up loss / Shut down loss
The start up loss occurs for the period of time preparing the line
for starting up and running in the equipment until conditions have
been stabilized. Yield losses occur when production is not
immediately stable at equipment start-up, so the first products do
not meet specifications. This is a latent loss, often accepted as
inevitable, and it can be surprisingly large.
Other downtime
Management losses and such waiting losses as (awaiting
instruction loss, awaiting material loss, awaiting personnel
distribution loss) and quality confirmation waiting loss
( Adjustment of measurement)
2) Equipment performance loss
(6) Minor stoppage and idling losses
(abnormal operation of sensors, blockage of work on chutes, etc.)
When a machine is running and stop / starting frequently, it will
lose speed and obstruct a smooth flow. The idling and stoppages
in this case are not caused by technical breakdowns, but small
problems such as product(s) that block sensors or get caught in
chutes. Even though the operator can easily correct such
problems when they occur, the frequent stoppages can
significantly reduce the effectiveness of the equipment.
(7) Speed loss
(discrepancies between designed and actual speed of equipment)
significantly reduce the effectiveness of the equipment.
Reduced speed operation refers to the difference between the
actual operating speed and the equipment’s designed speed (also
referred to as theoretical). There is often a gap between what
people believe is the “maximum” speed and the actual designed
(theoretical) maximum speed. The aim is to eliminate the gap
between the actual speed and the designed speed. Significant
losses from reduced speed operation are often neglected or
underestimated.
3) Defect loss
(8) Defects and rework loss
(ⅡⅡⅡⅡ) Losses in equipment loading time
Loss occurs when products do not meet quality specifications,
even if they can be reworked to correct the problem. The goal
should be zero defects – to make the product right first time, every
time.
(9) Shutdown loss
(10) Unused time loss
This is the period of time during the week where the equipment
is not staffed due no weekend working, bank holidays or factory
shutdown having an impact on loading time.
Other scheduled downtime losses due to no loading, no
material and labor shortage
Labour : 5 major losses
(ⅠⅠⅠⅠ) Production manhour loss
(11) Management loss
(such loss as awaiting instruction or material loss)
(12) Operating motions loss
(production manhour loss such as equipment breakdown loss
and equipment performance loss, method/procedure loss,
(ⅡⅡⅡⅡ) Line organization manhour loss
(13) Line organization loss
(line organization loss, loss due to breakdown to automate)
and equipment performance loss, method/procedure loss,
skill & morale loss)
(14) Logistics loss
(transportation loss)
(Ⅲ) Defect quality loss
(15) Measurement and adjustment loss
Material and energy : 3 major losses
(16) Material yield loss
defects quality loss, cutting loss, start-up loss, losses in
weight, losses in overages
start-up loss, overload loss, temperature loss
(17) Energy loss
(18) Maintenance spare parts loss
Cost of physical consumption of spare parts on
refurbishment of items on the line. (This loss does not
have an impact on OEE)
Other loss such as Jig & die loss
Definition of Overall Equipment EffectivenessDefinition of Overall Equipment Effectiveness
Overall equipment effectiveness = Availability x Performance rate x Quality rate
200
・ Breakdown losses
・ Setup and adjustment
losses
・ Startup losses
・ Idling and minor
stoppage losses
・ Reduced speed losses
・ Quality defect and rework losses
Efficiency =Output (constant)
Input Minimize
Excess amount of input = waste
Terminology : A comparison between efficiency
and effectiveness
201
Effectiveness =Output Maximize
Not effectively used input= lossesInput (constant)
Relationship between 7 Major Losses on Equipment and Relationship between 7 Major Losses on Equipment and
Overall Equipment EffectivenessOverall Equipment Effectiveness
Equipment 7 major losses
Loading time
Operating time
Downtime
loss
(1) Equipment failure
(2) Set-up & adjustment
(3) Cutting blade change
(4) Start-up
(5) Minor stoppage & idlingPerformance
Standard cycle time
Operating time× 100=
Availability460 mins. - 60 mins. 460 mins.
×100=87%=
(Example)
Product units processed
Availability Loading time - downtimeLoading time
× 100=
×
202
Perform
ance
loss
Net operating time
Value operating time
Defect loss
(5) Minor stoppage & idling
(6) Speed
(7) Defects & rework
Performance rate Operating time
× 100=
Performance rate 400 mins.
×100=50%=
(Example) 0.5 mins./ units ×
400 units
Quality products rate
Product units processed
Product units processed× 100=
- defect units
Quality products rate 400 units
×100=98%=
(Example)
400 units - 8 units
Overall Equipment Effectiveness = Availability x Performance Rate x Quality Products Rate
(Example) 0.87 x 0.50 x 0.98 x 100 = 42.6(%)
Cost deployment identifies 33 big losses in
case of process industries in general :
Equipment : 15 major losses
(i) 4 major losses in equipment loading time
(1) Unused time loss
This is the period of time during the week where the
equipment is not staffed due to no weekend working, bank
holidays or factory shutdown having an impact on loading
203
(2) Shutdown loss
Shutdown loss is time lost when production stops for planned
annual shutdown maintenance or periodic servicing.
(3) Production adjustment loss
Production adjustment loss is time lost when changes in supply
and demand require adjustment in production plans.
holidays or factory shutdown having an impact on loading
time.
(4) Maintenance time loss
(ii) 11 major losses obstructing overall plant effectiveness
1) Equipment downtime loss
(5) Equipment breakdown loss
Equipment breakdown loss is time lost when a plant stops
because equipment suddenly loses its specified functions.
(6) Process breakdown
204
(6) Process breakdown
lossProcess breakdown loss is time lost when a plant shuts down
as a result of factors external to the equipment, such as
operating errors or changes in the physical or chemical
properties of the substances being processed.
(7) Changeover loss
A changeover is determined by a planned variation in the
production plan or replacing tools / dies due to wear and tear or
being broken
(8) Setup loss and adjustment loss
Most machine changeovers require some period of shutdown so
that internal components can be exchanged or adjusted. The time between
the end of the last good product produced and the first good product
produced of the following production run is downtime. This downtime loss
often includes substantial time spent making adjustments until the machine
gives acceptable quality on the required product.
(9) Shortage of operators
205
This loss is time lost when a plant is stopping due to in-availability
of operators.
(10) Lack of material
This loss is time lost when a plant is stopping due to a lack of
material to process.
2) Equipment performance loss
(11) Minor stoppage and idling losses
(abnormal operation of sensors, blockage of work on chutes, etc.)
When a machine is running and stop / starting frequently, it will
lose speed and obstruct a smooth flow. The idling and stoppages
in this case are not caused by technical breakdowns, but small
problems such as product(s) that block sensors or get caught in
chutes. Even though the operator can easily correct such
problems when they occur, the frequent stoppages can
significantly reduce the effectiveness of the equipment.
206
significantly reduce the effectiveness of the equipment.
(12) Abnormal production loss/speed loss
Abnormal production losses are rate losses that occur when a plant
performs inadequately as a result of malfunctions and other
abnormal conditions that interfere with performance.
(13) Start-up loss / Shut down loss
The start up loss occurs for the period of time preparing the line for
starting up and running in the equipment until conditions have been
stabilized. Yield losses occur when production is not immediately stable
at equipment start-up, so the first products do not meet specifications.
This is a latent loss, often accepted as inevitable, and it can be
surprisingly large.
3) Defect loss
(14) Quality defect loss
207
Quality defect losses include time lost in producing rejects, physical
loss in scrap and financial losses due to product downgrading.
(15) Reprocessing loss
Reprocessing losses are recycling losses that occur when rejected
material must be returned to a previous process to make it acceptable.
Material and energy : 8 major losses
(16) Material yield loss
1. Defect quality loss
2. Cutting loss
3. Start up loss
(17) Unit consumption losses
208
(18) Raw material loss
(19) Overage
(20) Maintenance materials loss
(21) Leakage and spillage losses
(22) Inventory loss
(23) Energy loss
Labor : 10 major losses
209
(I) Production manhour loss
(24) Work losses
Work losses include wasteful human labor necessitated by a plant’s
poor operating condition. A plant that develops abnormalities or faults
generates extra work, such as inspecting and reporting on the faulty
equipment and making appropriate adjustments. Taking emergency
action and following up on process breakdowns characteristic of
process plants (leaks, spills, blocks and so on) require many work-
hours.
(25) Cleaning loss
(26) Inspection loss
(27) Lubrication loss
(28) Testing and analysis losses
(II) Line organization manhour loss
(29) Management losses
inspectioninspection
210
Management losses are losses that arise from poor management
systems or poor operation of those systems.
(30) breakdowns loss of not introducing new control systems of
personnel reduction
(31) breakdown loss of not centralizing and simplifying processes
(32) Logistics loss
(III) Defect quality loss
(33) Defect quality loss
The reason why losses must be divided into
different categories is because the method to
attack each categorized loss is different.
211
attack each categorized loss is different.
Bad Example from a World Class Manufacturing
companyLoss Type Definition examples: Machine Losses
Planned Maintenance
All planned maintenance time (machine hours and labour hours), and 25% of maintenance materials, all separated out by process step.
Breakdowns Machine or component breakdown (mechanical, electrical, electronical, hydraulic, pneumatic)
Process stops Process related machine stops (operator error, blockages, jam-ups, etc)
Start Loss Time from feeding materials until good product is produced
Other Downtime Material supply, raw material problems, electricity supply breakdown, contamination in supplied material
Changeover Time from last good product is produced of type A until first good product type B is produced
Speed Equivalent machine running time where the maximum achievable speed/throughput is not achieved
Defect / Rework Time where the machine is used to rework defective product, and time when machine is running to produce defective material
Example from a World Class Manufacturing company
Loss Type Definition examples: Labour Losses
Management Waiting for instructions from management (manager not on shift) or from someone outside the crew
Operator Motion Lost man-hours due to any kind of machine stop and time to sort/rework defects
Line Organisation
Man-hours spend at a machine where money was spent already to replace the operator or where technology is readily available
Scrap Transportation
Man-hours spend to transport defects and rework
Measurement & Adjustment
Man-hours needed to adjust the machine while good product is produced (anything which is not “no touch”)
Loss Type Definition examples: Material & Energy Losses
Process rejects Scrap generated as a “normal” part of the process, but without a breakdown.
Start Up Material used during start-up time
Overages Overages above the ideal formulations (beware of losses hidden in standards)
Energy Heat energy or electricity loss due to downtime, start-up, defects,
Example from a World Class Manufacturing company
Energy Heat energy or electricity loss due to downtime, start-up, defects, N or from sub-optimal energy usage
The structure of losses
Calendar time
Calendar time is the number of hours on the
calendar :
365 x 24 = 8,760 hours in a year
30 x 24 = 720 hours in a 30-day month.
215
30 x 24 = 720 hours in a 30-day month.
Working time
Working time is the actual number of hours that a
plant is expected to operate in a year or month. To calculate
working time, subtract from the calendar time the time lost as
a result of closing the plant for production adjustment or for
periodic servicing such as shutdown maintenance.
Operating time
Operating time is the time during which a plant
actually operates. To calculate operating time, subtract from
the working time the time a plant loses when it shuts down
as a result of equipment and process breakdowns.
Net operating time
216
Net operating time is the time during which a plant is
producing at the standard production rate. To calculate net
operating time, subtract performance time losses from the
operating time.
Availability
Availability is the operating time expressed as a
percentage of the calendar time.
Availability = Calendar time – (shutdown loss + major stoppage loss)
Calendar time
x 100 (%)
217
Shutdown losses = shutdown maintenance loss +
production adjustment loss
Major stoppage loss = equipment breakdown loss +
process breakdown loss
Performance rate
A plant’s performance rate expresses the actual
production rate as a percentage of the standard production rate.
The standard production rate is equivalent to a plant’s design
capacity and is the intrinsic capacity of a particular plant.
Performance rate =Average actual production rate (t/h)
Standard production rate (t/h)x 100(%)
218
(D)
(C)x 100(%)=
average actual
production rate
Actual production rate (t/h)
Operating time=
Quality rate
The quality rate expresses the amount of acceptable
product (total production less downgraded product, scrap,
and reprocessed product as a percentage of total
production.
Quality rate = Production quantity (t) – (quality defect loss + reprocessing loss) (t)
219
Quality rate = Production quantity (t)
(E)
(D)x 100 (%)=
Overall plant effectiveness
Overall plant effectiveness is the product of the availability,
performance rate, and quality rate.
220
221
Theoretical example of OPE :
222
223