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

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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

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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

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Maszyna

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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

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OVER

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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

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MIC

RO

STO

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OVER

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MPTIO

N

UN

BA

LAN

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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