Monodzukuri
Test

Learning Textbook

Japan Institute of Plant Maintenance

1

Chapter

Basics of
Production

Inspection Standard Manual

Operation Standard
ManualChapter 1

Basics of Production

1 Management by 5S
5S stands for the five Japanese words that start with an S: seiri (order/clearingup), seiton (arrangement), seiso (cleaning), seiketsu (neatness), and shitsuke(discipline). The 5S activities are well-known in Japan and throughout the world
alike.
Plant management starts with 5S. Workplaces without seiri and seiton cannot
produce good quality. Almost always, workplaces with low morale are disorderly
and lack discipline. Thorough implementation of seiri and seiton is the first step ofmaking a good workplace. See below for the definition of the 5S:① Seiri (order/clearing up): Distinguish between what are needed andwhat are not, and get rid of unnecessary things and things that should not
be seen in a workplace.
② Seiton (arrangement): Put necessary things in order so that they areeasy to use.
③ Seiso (cleaning): Make sure that everything is clean and well-maintained,
including the machines, dies, jigs, tools, measuring instruments. Also
make sure that the workers are clean and tidy—your hair, hands, working
clothes, and shoes—make it the usual.
④ Seiketu (neatness): Maintain high levels of seiri, seiton, and seiso.
⑤ Shitsuke (discipline): Train everybody so that they abide by the rules
and regulations. Make it a practice through mutual admonition.
Here, it is important that you understand the meaning of the 5S correctly.
If you put things away without sorting them, it is mere storage rather than seiri.
In seiton, you always need to consider efficiency—are they easy to fetch and use?
The objective is not to make the arrangement look good; make sure that you canfind necessary things without effort.

Try not to act superficially. Before implementing the 5S, you need to understand
why they should be done.

2

2

Quality

2 Quality
1 Basics of Quality Control
Job management has two sides: maintenance and improvement(Kaizen). In
maintenance, you need to keep the results of activities at the targeted levels. In
improvement, you need to set high levels of goals and achieve them.

In your daily work, you may be involved in a series of activities to change what

is not compatible with the goals or change the status quo that should not be.
These are typical improvement activities in your daily quality control.
The most important concept in supporting maintenance and improvement
is to speak on behalf of the data. This concept is also called fact-based
management. It is the foundation of quality control.
How can you efficiently speak on behalf of the data? Use the seven tools of QC
and statistical methods. They will help you process the data quantitatively andfind precise conclusions.
Learn the fundamental items that are essential in addressing quality issues
around you regarding production activities.

1

Management cycle

In maintenance and improvement alike, use the PDCA cycle as the principles
of job management around you. See Figure 1-1 for the outline of the PDCA
cycle.
Figure 1-1 Basics of management (turning the PDCA cycle)

Act

Check

Plan
Act

Plan

Check

Do

Higher level

Do

3

Chapter 1

Basics of Production

PDCA stands for plan, do, check, and act.
The P (plan) phase has two factors: deciding the objectives and goals, anddeciding the method of achieving the objectives and goals. The D (do) phase has
two factors: preparing for implementation, and implementing things as planned.
In the C (check) phase, check whether the results of the implementation meet theobjectives and goals. , In the A (act) phase, take necessary measures to address
the difference between the objectives/goals and the results. If the objectives
and goals have not been achieved, clarify the reason why and address it in youraction—change the way you do things in the next cycle, for instance. The starting
point need not be the P phase; you can start with the C phase by identifying thestatus quo and turn the CAPD cycle.

2

5W1H

When you collect and organize data or plan how to implement improvement
ideas, try 5W1H as the basic principles.
5W1H stands for ① who, ② what, ③ when, ④ where, ⑤ why, and ⑥ how. Whenyou speak on behalf of the data, the first thing you need to do before moving
on to the next step is to narrow the scope and capture facts and to make theimprovement activities concrete. (See 3-1, "Action Standards and 5W1H," Section
6, Chapter 4.)

3

PQCDSMEPQCDSME represents the indices of your daily activities. It stands for
production, quality, cost, delivery, safety, morale, and environment. Examples areshown below.
P : Total efficiency of equipment, number of failures, number of minor
stoppages
Q : Process defect rate, number of quality defects in local process,number of complaints on the market
C : Production cost, process defects, material cost
D : Raw materials, products in process, completed products in stock
S : Number of accidents causing major or minor injuries
M : Number of improvement suggestions, number of qualified or certified
people (Monodzukuri Test, for instance)
E : Monetary value of energy-saving, reduction in industrial wastes, numberof environmental improvements

To use these indices, you need to first identify the current values. If you do nothave a current value, collect data for at least three months during the preparation
period for the relevant activities and obtain the mean value. The current value

4

2

Qualityor the mean value is considered the starting value for the activities, and is called
the benchmark (BM). Clarifying the BM will allow you to set target values for the
future improvement activities.

4

The sangen (3 Gen) principles

As described earlier, speaking on behalf of the data, or fact-based management,is the foundation of quality control.
To identify facts, basically you need to make much of the three gens—genba(work site), genbutsu (actual product), and gensho/genjitsu (phenomenon/reality).
When an issue has occurred, you need to identify the fact by immediately goingto the work site and looking straight at the actual product and phenomenon. It

will allow you to pursue the cause properly and take necessary measures. Takecare to do it until it becomesa habit.

5

Building in quality in local process

Sampling inspection is a method of intermediate inspection of the products
output from a production line or the products in process. Certain quantities,
which are determined statistically, are sampled at random and tested (measured).
The products are deemed good or bad according to the test results.
Total inspection, in contrast, inspects each and every product. When total
inspection is done, most importantly, the customer who buys the productbelieves that the quality of all products is guaranteed by total inspection. Thus, aproduction system is demanded to work out ways to implement mechanisms thatwork like total inspection.
Basically, quality assurance should not depend on a particular inspection
process; assurance by the local process is the norm. The required quality needs to
be attained in the work processes; the subsequent processes must be considered
as customers. Poka yoke (preventing carless errors) measures, which prevent
people from Poka misu (committing careless errors), can be considered a methodof guaranteeing all products (100%).

2

The Seven Tools of QC

The Seven Tools of QC (Q7) is named after a Japanese legend—the seven toolsof Benkei. The seven tools are used widely in the field to analyze and manage
issues, and have proven effective in maintaining and improving quality. They
are the graph, Pareto diagram, cause-and-effect chart, check sheet, histogram,stratification, scatter diagram, and control chart. There are eight items but thename is seven—from time to time, the graph and control chart are united or
stratification is excluded.

5

Chapter 1

Basics of Production

Graph

1

Graphs are the most basic tool of statistical methods. The objective of using
statistical methods is to clarify how serious the issue is and what has caused

the issue. You cannot solve problems by using graphs alone. However, you can
express data as drawings rather than as numbers, thus stratifying the data invarious ways and estimating where the cause is.
It is very important to use the graph as a tool of problem-solving.

(1)

FigureBar graph

Bar graphs are intended to compare

two or more quantities, represented
by the lengths of the bars of a certain
width. Bar graphs can be vertical or
horizontal; vertical bar graphs are morecommon.
Bar graphs and line graphs are thetwo leading types of graphs. Bar graphs,
however, are the most popular actually(see Figure 1-2).

100
80# of defects(2)

1-2 Bar graph

60
40
20
0

4

6 （Month）

5

Circle graph

Circle graphs show the proportions of data as segments of a circle. A circle
graph is generated by ① collecting data, ② classifying the data according to theobjectives of the analysis, and ③ representing the proportions of the classified
items by radially dividing a circle into segments. The primary objective of a circle
graph is to compare the proportions.
Circle graphs have variations (see Figure 1-3)—circular breakdown graphs
or fan-shaped graphs (a), pie charts (b), and doughnut graphs that have an inner
Figure 1-3（a）Loss due to operation

Circle graph（b）

Judgment

Operation
12
Loss duetopeopleLoss due toequipment

People26

InformationLoss
86cases

Stock

Equipment
48

Arrangement

Operation
PeopleLoss

Equipment

Efﬁciency

Startup
Minor stoppage

6

Energy（c）

DefectMalfunction

Chapter2

Improving
Efficiency andCapturing
LossesChapter 2

Improving Efficiency and Capturing Losses

11

Basics of TPM®

Definition of TPM

TPM stands for total productive maintenance, which is a short for productive
maintenance in which all members participate.
TPM is defined as follows:
①
②

③

④
⑤

The objective is to create a corporate culture that pursues ultimate
efficiency of production systems (total efficiency).
Working mechanisms to prevent all kinds of losses, including zeroaccident, zero-defect, and zero-failure systems, are built on-site andwith actual products. The mechanisms cover the entire life cycle ofthe production system.
The efforts encompass all departments, including the development,
sales, and management departments, not to mention the production
department.
All members participate, from the top management to the front-line
employees.
A zero-loss state is achieved through overlapping small-group activities.

TPM requires the five items listed above. Implementing TPM in its true sense
requires implementing all the five items.

2

Basic concept of TPM

To deepen your understanding of TPM, check the following five keywords that
represent the fundamental principles related to the definition above.
Figure 2-1 shows the relationship between the TPM definitions and thefundamental principles.

54

1Figure 2-1

Definition and fundamental concept of TPM

Deﬁnition of company-wide TPM

Basic concepts of TPM

1. The objective is to create a corporate
culture that pursues ultimate eﬃciency of
production systems (total eﬃciency).

1. Building a proﬁtable corporate structure─ Pursuit of economic eﬃciency, zeroaccidents, zero defects, and zero failures

2. Working mechanisms to prevent all kindsof losses, including zero-accident,
zero-defect, and zero-failure systems, arebuilt on-site and with actual products. The
mechanisms cover the entire life cycle ofthe production system.

2. Preventive philosophy (prevention)－MP－PM－CM

3. The eﬀorts encompass all departments,
including the development, sales, andmanagement departments, not tomention the production department.

4. All members participate, from the top
management to the front-line employees.

5. A zero-loss state is achieved throughduplicated small-group activities.

①②③

Basics of TPM®

3. Total participation (management throughparticipation and respect for humanity)─ Duplicated small groups, autonomous
maintenance by operators

4. Priority placed on actual scenes andactual things
─ Making the equipment what it shouldbe, visual management, making theworkplace clean

5. Nurturing common sense─ Evolution and growth of the ways oflooking at things and thinking, while
ensuring continuity from the past④⑤

Building a profitable corporate structure
Preventive philosophy (prevention)
Total participation (management through participation and respect forhumanity)
Priority placed on actual work sites and actual things
Nurturing common sense1

Building a profitable corporate structure

By reducing defects and failures to a zero through TPM, customer satisfaction(CS)* will be maximized in terms of quality (Q), cost (C), and delivery (D).

2

Preventive philosophy (prevention)

The preventive philosophy is a concept that has been around since theintroduction of preventive maintenance and carried over to TPM.
*Customer satisfaction: The term originated in the U.S. in the 80's. People buy a productwhen they feel some sort of satisfaction with it. The degree of satisfaction should be regularly
evaluated, and the results should be used in developing or improving products. "Customer
first" has long been part of management concept, yet too much inclination to productivity andefficiency will not allow you to survive through the severe competition between companies. J. D.
Power and Associates is famous for providing related survey services.

55

Chapter 2

Improving Efficiency and Capturing Losses

3 Total participation (management through participation and respect for humanity)
Total participation is nothing but overlapping small-group activities. The
autonomous maintenance (Jishu-Hozen) activities by operators embody

management through participation and respect for humanity.
In TPM, small groups at different layers spontaneously define their goals—
zero defects or zero failures, for instance. They solve problems through total

participation to achieve the goals. All members share the sense of achievement
and success, thus their desire for growth is fulfilled.

4 Priority placed on actual work sites and actual things
TPM activities avoid conventional "serrated" improvement (Kaizen) activities(in which the original conditions tend to prevail for a certain period after
improvements and thus ups and downs are repeated). TPM activities aim toultimately minimize the losses of equipment throughout its lifespan, and promotebuilding a working mechanism that maintains good conditions (see Figure 2-2).
For that purpose, TPM activities address daily issues in the field under thefundamental concept of clarifying and handling true problems and causes,
always prioritizing the actual work sites, actual things, and reality. The activities
ensure that such an attitude takes root as corporate culture. Effective preventive
measures cannot be taken until this process is completed.

Loss

Figure 2-2

Development of
TPM activities
Mechanism for preventing problems
and maintaining a good condition

Zero level5

Nurturing common sense

People look at and think about things based on their past experience andlearning, which is called common sense. It is important that the common sense
be nurtured to suit the time and environment and thus human abilities shouldbe evolved and grown. Continuous nurturing allows continuous evolution andgrowth, thus leading to the prosperity of a company.

56

1

3

Basics of TPM®

TPM Objectives
Nurturing people

1

The objective of TPM, in short, is to revamp corporate structures by improving
people and equipment. In terms of people, TPM aims to nurture operators,
maintenance personnel, and production engineers who have the following skills:
・Operators: Autonomous maintenance skills to protect their own equipmenton their own

・Maintenance personnel: Skills to maintain mechatronics equipment* (suchas NC machines, industrial robots, and unattended carriers).
・Production engineers: Skills to plan and design equipment with highreliability and maintainability

2

Improving equipment (Kaizen of equipment)

Equipment is improved by improving people. The improvement is done in thefollowing two steps:(1)

Improving the existing equipment(2)

Improving new equipment and immediate startup

The first thing you should do is streamline the existing equipment. Implement
individual improvements (kobetsu kaizen) and autonomous maintenance to reduce
losses to a zero—downtime losses, setup and adjustment losses, minor stoppage
losses, and poor quality losses, for instance. Thus improve the equipment
currently used.

While improving existing equipment, you can obtain information that can be fed
back to the makeup of new equipment. The information is useful in implementing

LCC-conscious design and enabling immediate startup.
LCC stands for life cycle cost. LCC-conscious design minimizes the total costthroughout the equipment lifecycle, including the purchase and acquisition costs

and the operation and maintenance costs. In essence, LCC-conscious designmeans maintenance prevention (MP) in the design phase—designing equipment sothat known problems do not occur.
*Mechatronics equipment: Mechanical equipment incorporating expertise on electronics.
For instance, computers are introduced to the operation and control of machines to increase
their performance, implement automation, and save labor. The term mechatronics is acombination of mechanics and electronics, and was originated in Japan.

57

Chapter 2

Improving Efficiency and Capturing Losses

Immediate startup means full-scale production immediately after startup.
To enable immediate startup, you need to increase the quality of tasks in thedevelopment phase, including the designing of new equipment. For instance, you
should design new equipment taking care to prevent initial failures and problems
and enable full-scale production in month one, rather than scheduling a three-month period between installation and full-scale production. Thus, immediate
startup activities are intended to shorten the initial period of uncertainty (theperiod from the installation and trial operation to full-scale production) and thedevelopment lead time and to increase the overall efficiency.

4

Distinctive Features of TPM

The American PM is centered on the maintenance department based on theAmerican concept of functional specialization.
In contrast, TPM, the Japanese way of PM, is characterized by total
participation, particularly autonomous maintenance by operators (see Figure 2-3).
A distinctive feature of TPM is autonomous maintenance. Figure 2-4 shows thedifferences in the distinctive features between pre-TPM mainstreams (preventive
maintenance and productive maintenance) and TPM.

1

Pursuit of economy (profitable PM)

Pursuit of economy (profitable PM) is a feature of TPM. It was inherited fromthe time of preventive maintenance and productive maintenance.

2

Total system (MP—PM—CM)

The second feature of TPM is its focus on establishing a total system that
Figure 2-3

Distinctive features of TPM and differences with American PM

Distinctive features of TPM

American PM

TPM is intended for ultimate pursuit of total production systemeﬃciency.
─ TPM ultimately increases production eﬃciency by improving
how to make, use, and maintain equipment.

The American PM is led by equipment specialists,and ultimately pursues equipment eﬃciency by
improving how to make and maintain equipment.
However, it does not encompass how to use
equipment, thus fails to ultimately pursue total
production eﬃciency.

TPM is characterized by autonomous maintenance by
operators (protecting their own equipment on their own).
─ Operators handle routine maintenance (cleaning,lubrication, tightening, and inspection, for instance), andspecial maintenance staﬀ members closely inspect (diagnose)and repair the equipment.

In the American PM, operators focus on production(operation). All the maintenance work, including
routine maintenance, inspection, and repair, ishandled by the maintenance staﬀ.

TPM consists of small-group activities in which all members
participate
─ The small-group activities are conducted in solidarity withthe managers and technical staﬀ. All members, including the
top management, middle-level workers, and front-line workers.
Thus, the activities are called duplicated small-group activities.

The American PM does not involve small-group
activities in which all members participate.

58

Chapter3

Improvement
andAnalysis
Methods

Chapter 3

Improvement and Analysis Methods

1

Improvement (Kaizen) andAnalysis Techniques

Improving production efficiency requires a system that prevents all losses fromoccurring. You need to analyze the status quo, find problems, trace causes, andtake appropriate measures. This chapter describes several analysis methods thatare required in improvement (Kaizen) activities.

1

QC story

QC story shows the most fundamental steps of problem-solving. The steps are:
①
②
③
④
⑤
⑥
⑦
⑧

Setting a theme
Stating the reason that you have chosen the theme
Capturing the status quo, showing the problems based on data
Setting goals and planning activities
Analyzing the problems to reveal their causes
Taking measures against the causes
Checking the effectivenessStandardizing the measures (setting brakes) to prevent the situationfrom going backward⑨ Considering the remaining issues and what to do in the future
QC story was devised as a structure of reports to clearly describe the past
problem-solving cases. The QC story showed a well-organized procedure ofsolving problems, and people eventually found that activities in accordance with
the QC story work. Now it has taken root as a method of solving problems due tounknown causes.
For your information, Figure 3-1 shows the relationship between the methods
used in the different steps of the QC story. For 5W1H and the seven QC tools,
review Chapter 1, Basics of Production.

98

1

Improvement and Analysis Techniques

Figure 3-1 The QC story and analysis methods
No.

QC Story

1

Setting a theme: Stating the reason thatyou have chosen thetheme (Backgroundof the theme)

Recommended analysis method
Brainstorming
Cause-and-effect diagram

Capturing the status
quo

QC7

"Why-why" analysis
Check sheet

QC7(Matrix diagram)
2

Class

New QC7

Brainstorming
Cause-and-effect diagram
Graph, Pareto diagram, stratification

QC7

HistogramElement task analysis
3

Setting goals andplanning activities

5W1H
Gantt chart(PERT)

4

Analyzing causes

IE

New QC7

Brainstorming
Cause-and-effect chart
Stratification, scatter diagram

QC7

Correlation analysis"Why-why" analysis/PM analysis(Matrix diagram, tree diagram)
5

Taking measures

New QC7

5W1H(Matrix diagram, tree diagram)

New QC7

Gantt chart(PERT)New QC7"Why-why" analysis
6
7

Checking the effectivenessSetting brakes (standardization and having
the management takeroot)

Graph, radar chart

QC7

Histogram, Pareto diagram
5W1H
Graph, control chart

QC7

Standards, QC process table*In the Recommended analysis method column, a new QC7 tool is shown in parentheses.

99Chapter 3

Improvement and Analysis Methods

2

Brainstorming

Brainstorming is a team activity that involves free exchange of ideas. Somecompanies provide brainstorming opportunities in the form of a training
program, for instance, the Originality Development Course. It is intended for theparticipants to learn how to originate ideas, as inspired by the way geniuses think.
It is encouraged that the method be fully used in workplaces.

The four rules

1

Brainstorming is conducted under the following basic rules:① No criticism
Do not criticize the opinions from others, nor your own ideas. Being criticalprevents ideas from coming out.
(Typical criticism: "You can't do that," "It's costly," "I'm embarrassed," "I'd be
scolded," "People will laugh at me," and the like)② Freewheeling
Keep your mind free. Try to think from many points of view.
③ Quantity over quality
To get ideas, you should first give priority to quantity rather than quality.
④ Take advantage of others' ideas
Ideas can be associated. When you present an idea, it is effective to use thethinking of others.

Effective leverage

2

Leverage brainstorming in a team in the following ways, for instance:①

Plan two sessions for the discussion: discussing the problems fromthe viewpoints of all, and discussing countermeasures.
② Avoid criticism strictly. Producing ideas needs no criticism. Later inthe judgment phase, you will organize and select the ideas while using

criticism. In the judgment phase, you will make a judgment from theviewpoints of effectiveness, feasibility, and cost, for example.
③ Try the KJ method to organize the presented ideas. The KJ methodclassifies items into several groups according to their similarities. It
is effective to organize the ideas in the middle of the discussion; theparticipants can look at the organized ideas, and will be able to add

100

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Improvement and Analysis Techniques

freewheeling opinions under the "Take advantage of others' ideas(association)" rule above.

④ Familiarize yourself with the KJ method, and enjoy using it.

3"Why-why" analysis

In the event of a failure or anomaly such as a stoppage or defect, it isimportant to investigate why the cause happened, starting with the phenomenon
that occurred. Then, ask why again, that is, investigate the results of the firstinvestigation.
Repeat why over and over to find out all the causes (true causes) of failures andanomalies systematically, in the right order, and without omissions. Turn overthe last why to plan a precise countermeasure. This method is called "why-why"
analysis (see Figure 3-2).

Phenomenon
There are small
bugs in theworkplace.

Example of "why-why" analysis
Measures

Why ①

Why ②

Why ③

Why ④

The bugs
come fromtheoutside.

The bugs comewith theoutside air.

The inside air isblended with theoutside airs whenan operator opens
the door.

Double doors
are not
installed.

The bugs are on
the operators'
clothes.

The bugs cannot
be shaken oﬀ
outside theworkplace.

No air shower
is installed.

NG

There is no place
to change
clothes.

NG

The bugs areon the materialbags.

The environment
is suitable for thebugs.

The bugs are
generated in
the workplace.

OK

Install double
doors.

NG

Install an air
shower.

Examine if
clothes need
to be changed.

There are lights.
(shortwavelengths)

NG

There is a sugar
solution spilt
on the ﬂoor.

NG

Once a sugar solution is spilt,
immediately clean the ﬂoor.
Make it a rule.

Thetemperature is
30 to 40°C.

NG

Install an air-conditioner andset the temperature at 20°or
less.

The gutter isdirty.

NG

The bugs are
generated inside
the materials.

OK

Uselong-waveleng
th lights.

Determine priorities and implement countermeasures.

Figure 3-2

Regularly clean
the gutter, andrebuild it sothat waterdrains well.

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Chapter 3

Improvement and Analysis Methods

When implementing "why-why" analysis, keep the following in mind:(1)

Before using the method① Identify the problem as a specific fact.
Identify the problem clearly. A vague description like "The line has
stopped" is not sufficient. Capture the specific phenomenon, like "XX
has been disconnected." It is important to summarize the information
by 5W1H or stratification.

② Understand the structure and role (function) of the problem part.
(2) Once a series of "why-why" analysis is completed, backtrack the logic
from the last "why" to the starting phenomenon. Make sure that thepath is logical. This is the most vital point, so get accustomed to doing it

without fail.
(3) If you have never done "why-why" analysis before, many causes(factors) may not pop up in your mind. Cover your inexperience bychecking the actual work site, actual product, and phenomenon (reality)— the sangen (3 Gen) principle plus the fourth gen (genba, genbutsu,
gensho, and genjitsu).
(4) Avoid vague expressions of causes (factors), for instance:
・XX is bad.
・I was tired.
・I felt faint.
・I was busy producing something.

4

PM analysis
PM analysis

1

PM analysis is a method and concept of analysis intended for reducing chronic
losses (defects and failures). It analyzes the subject phenomena physically andclarifies the mechanisms. Thus, it is called PM analysis.
PM analysis consists of the following steps:①

Carification of phenomena—Stratifying the phenomenon sufficiently*②③④

Physical analysis of phenomena
Conditions defining phenomena(Details are given later)

Study of relations with equipment (including jigs/tools), materials, andmethods—Listing all the probable causes of the conditions.

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Chapter

4

RoutineMaintenance ofEquipment(Autonomous Maintenancein General)Chapter 4

Improvement and Analysis Methods

1 Basic Knowledge about Autonomous
Maintenance (Jishu-Hozen)
1 Autonomous maintenance (Jishu-Hozen)
1

Why is autonomous maintenance required?

What does a company need to survive? In recent years, companies havebecome increasingly aware of the importance of maintenance activities. Thus,
need has arisen for the companies to review their operators and maintenancetasks.
Meanwhile, small-group activities, including QC circles and ZD (zero defect)groups, are widespread today, and people have gotten used to managing their own
tasks spontaneously. This idea has strengthened and evolved into the concept ofautonomous maintenance—protecting one's own equipment on one's own.

2

Protecting one's own equipment on one's own

Equipment has been becoming more advanced and complex with company
scales expanding and technologies making remarkable progress.
Accordingly, the concept of "I make, you fix" has taken root gradually. The
production department focuses on production, leaving equipment maintenance tothe maintenance department.
As a result, people involved with production just make things—setting andremoving works or starting and stopping the equipment. They leave everything
related to equipment to the maintenance people, including repairs and lubrication,and quality check to the inspection people. That idea, however, has become amajor obstacle to companies intending to improve productivity.
Today, prevention has become essential for equipment health maintenance.
Just like preventing diseases, you need to prevent equipment failures and quality

defects. However, the maintenance department has only a limited number of＊

QC circle: A small group that autonomously conducts quality control activities within aworkplace. The members enlighten themselves and each other as part of company-wide
quality control activities, and use the QC methods to continuously manage and improve theworkplace through participation by all.
†ZD (zero defect): A movement in which people endeavor to rectify their weak points andperform proper tasks (operations), thus eliminating defects. ZD and TPM share the samezero-oriented concept. Yet you can say that TPM is more severe, as it considers attaining
zero is required rather than desired.

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1

Basic Knowledge about Autonomous Maintenancepeople; there may be too many pieces of equipment for them to cover. Thus,
operators have to share a part of maintenance work in their routine managementtasks.
The routine maintenance (daily maintenance) tasks by operators are calledautonomous maintenance by operators. Operators do what they can do on their own:
for instance, inspect the equipment daily, find anomalies early, check the equipment
for precision, lubricate the equipment, replace some parts, and make easy repairs.
In other words, each and every operator protects the equipment on their own.

3

Proficient equipment operators

Autonomous maintenance requires each and every operator to be proficient in

operation and maintenance. An operator has to be able to operate the equipment
correctly, of course. Further, the operator has to be able to perform routine
maintenance—cleaning, inspection, and lubrication, for instance. The more theequipment is automated and robotized, the higher the need for autonomous
maintenance.
To be proficient in equipment operation and maintenance, an operator firstneeds to be able to find anomalies. The operator has to have skills of detecting
anomalies (to be a good judge), being able to say "Something is wrong!" withquality or equipment. Namely, a proficient operator has to have the following four
skills:①②Detect anomalies as anomalies (anomaly finding skill),
Immediately take proper action on the anomalies (treatment andrecovery skill),③ Determine quantitative judging criteria for proper operation andanomalies (condition setting skill), and④ Abide by the predetermined rules (maintenance and management
skill).
Specifically, each and every operator has to be able to:①

Find and rectify defects of equipment,② Find causes ＊ of anomalies based on the knowledge on the equipment
structure and functions,③ Predict quality anomalies and find causes＊ based on theunderstanding of the relationship between equipment and quality, and④ Repair equipment.

＊ Causes: Factors that can cause failures and defects, such as vibrations due to loose bolts,
wear due to poor lubrication, and abnormal heat.

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Chapter 4

Improvement and Analysis Methods

Figure 4-1

Steps to a proficient equipment operator

4
3
2
1

Able to make minor
repairs on the equipment

Understands the relationshipbetween the 4M conditions(machine, material, man, andmethod) and product quality

Knows the functions and structure of
the equipment

Able to see ﬂaws as ﬂaws, and have learned
the ways of thinking required for equipment
improvement and the actions to take

An operator truly proﬁcientin equipment

Skills of maintenance andmanagement

Skill to set up conditions

Skills to ﬁnd anomalies
Skills to address and rectify
anomalies

Those skills cannot be acquired at one time. Through the steps of autonomous
maintenance activities, an operator should learn the skills one by one (see Figure
4-1).

4 Concept of implementing autonomous maintenance activities
The "I make, you fix" attitude in the field has brought about many evils that
impede equipment efficiency. Autonomous maintenance was conceived to correct
the situation.
The essential tasks of an operator is to operate equipment and process orassemble products. An operator may not be familiar with sharing part of themaintenance work. Thus, to make autonomous maintenance familiar to theoperators, autonomous maintenance activities are implemented. The fundamental
concept of autonomous maintenance activities is as described below.
<Fundamental concept>① Equipment failures and quality defects can be reduced to a zero if all people
involved with the equipment correct their way of thinking and behavior.
② Changing the equipment changes people. Changing people changes theworkplace.
③

The management leads the activities, and all members participate. The
activities are conducted in steps, making sure that the participants arebrought to a higher level.
Bringing workers to a higher level through participation by all—that is the coreidea of autonomous maintenance activities (see Figure 4-2).

116

1

Figure 4-2

Basic Knowledge about Autonomous Maintenance

Implementing autonomous maintenance activities in steps
Changes in theways of thinking

Step zero(preparation)

Step 1
Step 2
Step 3

Motivation

Change theequipment.

Thinking andacting●Motivation comesfrom the processesof action.
Have the members
think how forced
deterioration
occurs and see
why autonomous
maintenance isrequired now.

2

Correcting ﬂaws

Step 4
Step 5Eﬀectiveness

Peoplechange.

Reduceddefects
and failures

Changes in
activities
・Aggressive
involvement in
improvement
・Permeation ofmaintenance andmanagementawareness●Cleaning means inspection.
●Inspection means discovery
of ﬂaws.
● Flaws require rectiﬁcation andimprovement
Enhance ﬂaw-ﬁnding abilities
and improvement philosophies

CFailures bringshame on theworkplace.

Eﬀectiveness
Actualexamples ofzero-defectandzero-failure
achievements●Equipment improved or restored fromdeterioration is the fruit of labor.
●The fruit of labor means joy of achievement.

Step 6
Step 7
The workplacechanges.

●ottom-up decision-making
from the circle● Members create tasks required
for the solutions on their own.

〔People and their ways of thinking do not change unless they see tangible results.〕

 oles and activities of production andRmaintenance departments

1 Roles of production and maintenance departments in autonomous maintenance
Quite often, the maintenance department has a passive attitude—doing
construction work upon request from the production department. It even looks
as if the maintenance department is doing it out of generosity. When a piece ofequipment fails, it is natural that the production department wants it repaired assoon as possible. Thus, the production department tends to ask for help. And themaintenance department may be too busy. They may have too many requests forconstruction work to deal with. Thus, before they know, they tend to take the wegenerously-do-it-for-you attitude.
Productivity cannot be improved when the two departments are in that kind of
relationship.
The production department must take on the activities to prevent deterioration,
which is the foundation of maintenance.

People of the production department handle the equipment every day, so they
are the best people to take on the fundamental maintenance role—detecting
minor anomalies. With responsibilities thus assigned, the maintenance department
can demonstrate the true performance of its special maintenance schemes. It is
the first step toward efficient maintenance.

2 Classification of maintenance schemes and assignment of responsibilities
This section classifies the maintenance schemes and what responsibilities

should be assigned to autonomous maintenance (see Figure 4-3).

117

Chapter 4

Improvement and Analysis Methods

Figure 4-3

Classification of maintenance schemes and assignment ofresponsibilities

Classiﬁcation of schemes

Preventive maintenance

Normaloperation

Measuring
deterioration

Rectifying
deterioration

Production Maintenance

Correct operation
Setup and adjustment
Cleaning, extraction of potential defects,
measures

Routineinspection

Lubrication
Retightening
Routine inspection of operating
conditions and deterioration
Minor
maintenance
Periodic inspection

Periodicmaintenance

Productive maintenance

Responsibilities

Activities

Preventing
deterioration

Periodic examination
Periodic overhaul
Trend inspection

Predictive
maintenance

Unscheduled
maintenance

Breakdown
maintenance

Maintenanceprevention

Corrective maintenanceImproved strength
Corrective
maintenance(reliability)

Reduced load
Improved precision

Corrective
maintenance(maintainability)

Developing condition
monitoring
Improving inspection work

Operability,
safety,and others

Improving
maintenance work
Improving
maintenance quality

MP activities
Planned breakdown
maintenance
Finding issues early and quickly and surely
reporting actions taken
Emergency
maintenance

Emergency repair

The activities for attaining the maintenance goals are largely classified into thefollowing two:①②

Maintenance activities: Preventing failures and repairing failures
Improvement (Kaizen) activities: Extending service life and shortening

maintenance time118

Chapter5

Basics of
RoutineMaintenanceChapter 5

Basics of Routine Maintenance

1 Basics of Routine Maintenance(Daily Maintenance)
1

Fastened components

Mechanical elements are diverse: screws, rivets, keys, cotters, geartransmissions, axles, bearings, links, cams, pipes, joints, and more. It is probably
impossible to attain proficiency in all of them; and it is not necessary to do so.

This section describes the very basics of mechanical elements—fasteners such as
screws and rivets. They are probably the most frequently used components, andaffect the precision of machines and the likelihood of failures.

1

Precision of machines

Machining tools and presses should be checked for precision at least once ayear. Maintaining precision enables good products to be produced safely and at
low cost. In overall inspection, check the following items as far as you can andclarify whether anomalies are present:① Machine center② Table levelness③ Main axis squareness and deflection

2

Fastening

There are many types of fasteners: keys, rivets, pins, cotters, splines, andscrews, for instance. Figure 5-1 shows their roles, rough sketches, primary
applications, and checkpoints in overall inspection.

3(1)

Bolts and nuts
Principles of screws

When a piece of paper in the shape of a right triangle is wrapped around acylinder, the long side forms a spiral. This spiral is called a helix.
The angle that shows the inclination of a helix ( β ) is called a lead angle.
By combining a cylindrical object with a groove along the helix on the outsidewith another cylindrical object with the same groove on the inside, you can turna small force into a large fastening force or change circular motion into linear
motion (and vice versa) (see Figure 5 (and vice versa) (see Figure 5-2).

198

1

Figure 5-1

Basics of Routine Maintenance

Types of fasteners and their characteristics
Roles and rough sketch

Applications

Checkpoints

Transmission of torque(Example)

Retaining gear,
coupling,
sprocket, or
pulley onto
shaft

①Noise②Too much play
③Wear
④Stepping⑤Looseness

Fastener type1. KeyParallel key(embedded key)
Taper key (Driving key)
Woodruﬀ key

Driving key
2. Rivet
Round-head rivet
Countersunk rivet
Thin ﬂat rivet
Pan-head rivet
Flathead rivet
Others

Couplings and joints

Pressure vessel(boiler)
BridgeBuilding
AircraftCrane①Looseness②Corrosion③Wear④Too much play
⑤Bend

3. Pins
Tapered pin
Parallel pin
Cotter pin
Spring pin

Fastening, retaining, locking, Steering
positioning
Chain(Example) Taper 1/50
Retaining parts
Positioning①Noise②Rust (corrosion)③Wear④Omission⑤Racing

4. Cotter
Single-sided
Double-sided

Fastening shafts that receive
both tensile and compressive
strengths
CotterTapered pin
Locomotive
Car pedal①Noise②Too much play
③Wear

SocketSee subsection 3, Bolts and nuts.

5. Bolts and nuts

Figure 5-2

Principles of screws

Principles of screws
d

3
12

4

B
6

5

A

Lead angle

β

1 2 3 4 5 6

πd

A
1

(2)

2 3 4

6
5

Helix
Helix angle

L
C
Lead L

Tangential
line of helixαβrBasics of screws① Male and female screws
When a cylinder has a groove along a helix on the outside, it is called a malescrew. When a cylinder has a groove along a helix on the inside, it is called afemale screw.

199

Chapter 5

Basics of Routine Maintenance② Single- and multi-thread screws
A screw of a single helix is called a single-thread screw. A screw with two or

more helixes is called a multi-thread screw.
③

Lead and pitch

The distance between the center lines of two adjacent ridges is called a pitch (p).
The distance which a ridge travels when a screw is turned once is called a lead(L). When the lead is expressed as L, the pitch as p, and the number of threads asn, the following relationship is established: L ＝ p × n. With a single-thread screw,
the formula is L ＝ p. Thus, a multi-thread screw is tightened more quickly than asingle-thread screw for the same number of turns.
④ Effective diameter
The effective diameter (d2 or D2) of a screw is the diameter of an imaginary
cylinder that exists where the thread ridge thickness is equal to the thread valley
width.
5-3 Structure of thread°90

d : Outer diameter of male thread
d1 : Root diameter of male thread
d2 : Eﬀective diameter of male thread
D : Root diameter of female thread

Figure 5-4

D1 : Inner diameter of female thread
D2 : Eﬀective diameter of female thread
P : Pitch
H : 0.866025P

Types and characteristics of triangular threads

Name

Thread shape Unit ofThreadangle Ridge Groove pitch

Meter thread

60 °

Flat

Round

Uniﬁedthread60 °FlatThreads
Round per inchWhitthread55 ° Round Round per inch

Inch
thread200

Axis of threadd or DH
2P

d2 or D2

Male thread

d1 or D1

30° 30°60°

H

H

Femalethread

H
4

H
2

H
8

Figuremm

Nominaldiametermm

Numberor inchThreads Coarse thread: inch;
Fine thread: mm

1

Basics of Routine MaintenanceWith a male screw, the outer diameter (crest-to-crest diameter) is called d andthe diameter of the valley (root-to-root diameter) is called d1 (see Figure 5-3).
⑤ Nominal diameter
The nominal diameter of a crew represents its size. Mainly, the nominal
diameter is the reference size of the outer diameter of the male thread. In Figure
5-3, the nominal diameter is the outer diameter d of the male thread.

(3)

Mechanical properties of screw components

Screw components are for fastening two or more parts, and their most importantconditions are their mechanical properties. Difficult theories aside, you can easily
imagine that you will be in trouble if the two components are torn when pulled.

Thus, tensile strength is important.
The tensile strength is the reference for the various mechanical strengths ofbolts and nuts, which are assigned strength classes. Tensile strengths are indicatedby the symbol T—4T or 10T, for instance.

(4)

How bolts and nuts are tightened

Imagine fastening two flanges with a bolt and a nut. As you tighten the nut, thebolt is pulled longitudinally. As a result, it is stretched longitudinally, though only
slightly.
Inside the bolt, a tensile stress is generated in accordance with the pulling
force (axial force).The generated tensile stress fastens the flanges via the seat of
the nut. In accordance with
Figure 5-5 Stretch of a bolt
the axial force, a compressive
stress works on the flanges.
StretchA steel bolt is stretched whentightened, though it is not
Tensile stressvisible to the naked eye. Whatgenerated
inside the bolt
tightens the object is theelastic force of the stretched
Flangebolt shrinking to the original
length. Figure 5-5 shows thestretch of a bolt.

(5)

Fastening force of bolts and nuts (tightening torque)

Appropriate tightening means to give the necessary axial force to the bolt.

Generally, you use a wrench to tighten a bolt. Specifically, you use a wrench to
apply a tightening torque (turning torque) to the nut to generate the necessary
axial force (fastening force).
The tightening torque is the product of the distance L from the axial center of201

Chapter 5

Basics of Routine Maintenancethe bolt to the point of action and theturning force F (see Figure 5-6).

Figure 5-6

Tightening a bolt and a nut

The tightening torque is expressed
as follows:

LF

T ＝ F × L (kgf･cm）(6)①

Loosening of bolts and nuts

How does a bolt loosen?

Loosening of bolts and nuts frequently occur in the following places:
・Where impulse load is applied

・Where vibration is likely
・Where temperature changes are severe
・Where bolts and nuts are used on internal structures of a machine or device
and are difficult to maintain or manage
Figure 5-7 shows the types of screw loosening.
Figure 5-7

Types of screw loosening

Nut rotation

Cause of loosening

The nut does not turnin loosening direction.

①Wear of micro irregularities on the contact area
②Seat subsiding into fastened object③Worn gasket④Wear of contact area due to micro motions⑤Heat

The nut turns inloosening direction.

⑥Impulsive external force⑦Relative displacement of fastened objects② Loosening as a phenomenon
What is the loosening of a screw? It is a phenomenon in which the axial force
that has been generated by tightening a bolt is reduced below the required level
or disappears.
③ Loosening that occurs without a nut turning• Loss of micro roughness of joined surfaces
As shown in Figure 5-8, objects fastened with a screw have surfaces that are

joined under compressive force—the seats of the bolts and nuts, and the surfacesof the objects themselves, for instance.
The joined surfaces have micro roughness, which is squashed and flattened by
the fluctuating bearing stress. The distance between the objects is shortened asshown in Figure 5-9, and so is the tightening length. Thus, the axial force of thebolt decreases.

202