-
An Introduction to Total Productive
Maintenance (TPM)
In today’s industrial
scenario huge losses/wastage occur in the
manufacturing shop floor. This waste
is
due to operators, maintenance personal, process,
tooling problems and non-availability of
components in
time etc. Other forms of
waste includes idle machines, idle manpower, break
down machine, rejected parts
etc
are
all
examples
of
waste.
The
quality
related
waste
are
of
significant
importance
as
they
matter
the
company in
terms of time, material
and
the hard earned reputation
of the
company. There
are
also
other
invisible wastes like
operating the machines below the rated speed,
start up loss, break down of the machines
and bottle necks in process. Zero
oriented concepts such as zero tolerance for
waste, defects, break down and
zero
accidents are becoming a pre-requisite in the
manufacturing and assembly industry. In this
situation, a
revolutionary concept of
TPM has been adopted in many industries across the
world to address the above said
problems. This chapter deals in length
about this TPM.
What is Total Productive Maintenance
(TPM)?
It can be
considered as the medical science of machines.
Total Productive Maintenance (TPM) is
a
maintenance program, which
involves a newly defined concept for maintaining
plants and equipment. The
goal of the
TPM program is to markedly increase production
while, at the same time, increasing employee
morale and job satisfaction.
TPM brings maintenance into
focus as a necessary and vitally important part of
the business. It is no
longer
regarded
as
a
non-profit
activity.
Down
time
for
maintenance
is
scheduled
as
a
part
of
the
manufacturing day and, in some cases,
as an integral part of the manufacturing process.
The goal is to hold
emergency and
unscheduled maintenance to a minimum.
Why TPM?
TPM was introduced to
achieve the following objectives. The important
ones are listed below.
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Avoid wastage
in a quickly changing economic environment.
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?
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Producing goods without reducing
product
quality.
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Reduce
cost.
?
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Produce a low batch quantity at the
earliest possible time.
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?
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Goods send to the
customers must be non-
defective.
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Similarities and differences between
TQM and TPM:
The
TPM program closely resembles the popular Total
Quality Management (TQM) program. Many
of the tools such as employee
empowerment, benchmarking, documentation, etc.
used in TQM are used to
implement and
optimize TPM. Following are the similarities
between the two.
1. Total commitment to the program by
upper level management is required in both
programmes
1
2.
Employees must be empowered to initiate
corrective action, and
3.
A long-range outlook must be accepted
as TPM may take a year or more to implement and is
an on-
going process. Changes in
employee mind-set toward their job
responsibilities must take place as well.
The
differences
between TQM and TPM are summarized
below.
Category
TQM
TPM
Object
Quality (Output and effects)
Equipment (Input and
cause)
Systematize the
management. It is
Mains of
attaining goal
software
oriented
Employees
participation
and
it
is hardware
oriented
Target
Quality for PPM
Elimination
wastes.
of
losses
and
Types of
maintenance:
1.
Breakdown maintenance:
In this type of maintenance, no care is
taken for the machine, until equipment fails.
Repair is then
undertaken. This type of
maintenance could be used when the equipment
failure does not significantly affect
the operation or production or generate
any significant loss other than repair cost.
However, an important
aspect
is
that
the
failure
of
a
component
from
a
big
machine
may
be
injurious
to
the
operator.
Hence
breakdown maintenance
should be avoided.
2. Preventive maintenance
(1951):
It is a
daily maintenance (cleaning, inspection, oiling
and re-tightening), design to retain the healthy
condition of equipment and prevent
failure through the prevention of deterioration,
periodic inspection or
equipment
condition diagnosis, to measure deterioration. It
is further divided into periodic maintenance and
predictive maintenance. Just like human
life is extended by preventive medicine, the
equipment service life
can be prolonged
by doing preventive maintenance.
2a. Periodic maintenance
(Time based maintenance - TBM):
Time based maintenance
consists of periodically inspecting, servicing and
cleaning
equipment
and
replacing
parts
to
prevent
sudden
failure
and
process
problems.
E.g.
Replacement
of coolant or oil every 15 days.
2b. Predictive
maintenance:
This
is
a
method
in
which
the
service
life
of
important
part
is
predicted
based
on
inspection
or
diagnosis, in order to use the parts to
the limit of their service life. Compared to
periodic maintenance,
predictive
maintenance is condition-based maintenance. It
manages trend values, by measuring and
analyzing data about deterioration and
employs a surveillance system, designed to monitor
conditions
through an on-line system.
E.g. Replacement of
coolant or oil, if there is a change in
colour. Change
2
in colour indicates the deteriorating
condition of the oil. As this is a condition-based
maintenance, the
oil or coolant is
replaced.
3.
Corrective maintenance (1957):
It improves equipment and
its components so that preventive maintenance can
be carried out reliably.
Equipment with
design weakness must be redesigned to improve
reliability or improving maintainability. This
happens at the equipment user level.
E.g. Installing a guard, to prevent the burrs
falling in the coolant tank.
4. Maintenance prevention
(1960):
This
program indicates the design of new equipment.
Weakness of current machines is sufficiently
studied (on site information leading to
failure prevention, easier maintenance and
prevents of defects, safety
and ease of
manufacturing). The observations and the study
made are shared with the equipment manufacturer
and necessary changes are made in the
design of new machine.
TPM - History:
TPM
is
an
innovative
Japanese
concept.
The
origin
of
TPM
can
be
traced
back
to
1951
when
preventive maintenance
was introduced in Japan. However the concept of
preventive maintenance was taken
from
USA. Nippondenso
was the
first
company to
introduce
plant wide preventive maintenance in
1960.
Preventive
maintenance
is
the
concept
wherein,
operators
produced
goods
using
machines
and
the
maintenance group was dedicated with
work of maintaining those machines, however with
the automation of
Nippondenso,
maintenance
became
a
problem,
as
more
maintenance
personnel
were
required.
So
the
management
decided
that
the
operators
would
carry
out
the
routine
maintenance
of
equipment.
(This
is
Autonomous
maintenance,
one
of
the
features
of
TPM).
Maintenance
group
took
up
only
essential
maintenance
works.
Thus
Nippondenso,
which
already
followed
preventive
maintenance,
also
added
Autonomous
maintenance done
by production operators. The maintenance crew went
in the equipment modification for
improving
reliability.
The
modifications
were
made
or
incorporated
in
new
equipment.
This
lead
to
maintenance
prevention.
Thus
preventive
maintenance
along
with
Maintenance
prevention
and
Maintainability Improvement
gave birth to
Productive maintenance
. The
aim of productive maintenance
was
to maximize plant and
equipment effectiveness.
By
then
Nippon
Denso
had
made
quality
circles,
involving
the
employees
participation.
Thus
all
employees took part in implementing
Productive maintenance. Based on these
developments Nippondenso
was awarded
the distinguished plant prize for developing and
implementing TPM, by the
Japanese
Institute
of Plant Engineers
(JIPE). Thus Nippondenso of the Toyota
group became the first company to obtain
the
TPM
certification.
3
TPM Targets:
1.
2.
3.
4.
5.
6.
7.
Obtain Minimum
90% OEE (Overall Equipment Effectiveness)
Run the machines even during lunch.
(Lunch is for operators and not for machines!)
Operate in a manner, so that there are
no customer complaints.
Reduce the
manufacturing cost by 30%.
Achieve 100%
success in delivering the goods as required by the
customer.
Maintain an accident free
environment.
Increase the suggestions
from the workers/employees by 3 times. Develop
Multi-skilled and flexible
workers.
Motives of TPM
1.
Adoption of
life cycle approach for improving the overall
performance of production equipment.
2.
Improving
productivity by highly motivated workers, which is
achieved by job enlargement.
3.
The use of
voluntary small group activities for identifying
the
cause of failure, possible plant
and equipment modifications.
Uniqueness of TPM
The major difference between TPM and
other concepts is that the operators
are also
made to
involve in
the maintenance
process.
The concept
of
(Production operators)
Operate, You (Maintenance
department) fix
is not
followed.
TPM Objectives
1.
Achieve Zero
Defects, Zero Breakdown and Zero accidents in all
functional areas of the organization.
2.
Involve people
in all levels of organization.
3.
Form different
teams to reduce defects and self-Maintenance.
Direct benefits
of TPM
1.
2.
3.
4.
5.
Increase in
productivity and OEE (Overall Equipment
Efficiency)
Reduction in customer
complaints.
Reduction in the
manufacturing cost by 30%.
Satisfying
the customers needs by 100 % (Delivering the right
quantity at the right time, in the
required quality.)
Reduced accidents.
Indirect benefits of TPM
1.
2.
3.
4.
5.
Higher confidence level among the
employees.
A clean, neat and attractive
work place.
Favourable change in the
attitude of the operators.
Achieve
goals by working as team.
Horizontal
deployment of a new concept in all areas of the
organization.
6.
Sharing knowledge and
experience.
7.
The workers get a feeling of owning the
machine.
4
OEE (Overall
Equipment Efficiency):
The basic measure associated with Total
Productive Maintenance (TPM) is the OEE. This OEE
highlights the
actual
not
an exclusive measure of
how well the maintenance
department
works. The design and installation of equipment as
well as how it is operated and maintained
affect the OEE. It measures both
efficiency (doing things right) and effectiveness
(doing the right things) with
the
equipment. It incorporates three basic indicators
of equipment performance and reliability. Thus OEE
is a
function of the three factors
mentioned below.
1.
Availability
or uptime (downtime: planned and unplanned, tool
change, tool service, job change etc.)
2.
Performance
efficiency (actual vs. design capacity)
3.
Rate of
quality output (Defects and rework)
Thus
OEE = A x PE x
Q
A - Availability of the
machine
. Availability is proportion of
time machine is actually available out of
time
it
should be
available.
Availability = (Planned
production time
–
unscheduled downtime)
Planned production time
Production time = Planned production
time
–
Downtime
Gross available hours for
production include 365 days per year, 24 hours per
day, 7 days per week.
However this is
an ideal condition. Planned downtime includes
vacation, holidays, and not enough loads.
Availability
losses
include
equipment
failures
and
changeovers
indicating
situations
when
the
line
is
not
running although it is
expected to run.
PE - Performance Efficiency
.
The second category of OEE is performance. The
formula can be expressed
in
this way:
5
Performance (Speed) = (Cycle time x
Number of products processed)
Production time
Net production time is the time during
which the products are actually produced. Speed
losses, small stops,
idling, and empty
positions in the line indicate that the line is
running, but it is not providing the quantity it
should.
Q - Refers to quality rate.
Which is percentage of good parts out
of total produced. Sometimes called
“yield”.
Quality losses
refer to the situation when the line is producing,
but there are quality losses due to in-progress
production and warm up rejects. We can
express a formula for quality like
this:
Quality (Yield) = (Number
of products processed
–
Number of products rejected)
(Number of products
processed)
A simple example
on how OEE is calculated is shown
below.
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Running 70 percent of the time (in a
24-hour day)
?
?
Operating at 72 percent of design
capacity (flow, cycles, units per
hour)
?
?
Producing quality output 99 percent of
the time
?
?
When the three factors are considered
together (70% availability x 72% efficiency x 99%
quality), the
result is an overall
equipment effectiveness rating of 49.9
percent.
Stages
in TPM implementation:
Step A - PREPARATORY STAGE:
STEP 1 - Announcement by
Management to all about TPM introduction in the
organization:
Proper understanding, commitment and
active involvement of the top management in
needed
for
this
step.
Senior
management
should
have
awareness
programmes,
after
which
announcement is made.
Decision the implement TPM is published in the in
house magazine,
displayed
on
the
notice
boards
and
a
letter
informing
the
same
is
send
to
suppliers
and
customers.
STEP 2 - Initial education and
propaganda for TPM:
Training is to be done based on the
need. Some need intensive training and some just
awareness training based on the
knowledge of employees in maintenance.
STEP 3 - Setting up TPM and
departmental committees:
TPM includes improvement, autonomous
maintenance, quality maintenance etc., as
part of it. When committees are set up
it should take care of all those needs.
STEP 4 - Establishing the
TPM working system and target:
Each area/work station is benchmarked
and target is fixed up for achievement.
6
STEP 5 - A
master plan for institutionalizing:
Next step is implementation
leading to institutionalizing wherein TPM becomes
an
organizational culture. Achieving PM
award is the proof of reaching a satisfactory
level.
STEP B -
INTRODUCTION STAGE
A
small
get-
together,
which
includes
our
suppliers
and
customer’s
participation,
is
conducted.
Suppliers as they should know that we
want quality supply from them. People from related
companies and
affiliated companies who
can be our customers, sisters concerns etc. are
also invited. Some may learn from
us
and some can help us and customers will get the
message from us that we care for quality output,
cost and
keeping to delivery
schedules.
STAGE
C - IMPLEMENTATION
In this stage eight
activities are carried which are called
eight
pillars
in
the development
of TPM
activity. Of these four activities are
for establishing the system for production
efficiency, one for initial control
system of new products and equipment,
one for improving the efficiency of administration
and are for control
of safety,
sanitation as working environment.
STAGE D -
INSTITUTIONALISING STAGE
By now the TPM implementation
activities would have reached maturity stage. Now
is the time to
apply for PM
award.
TPM
Organization Structure:
7
Pillars of TPM:-
PILLAR 1
–
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Work
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TPM starts with 5S. It is a systematic
process of housekeeping to achieve a serene
environment in the
work place involving
the employees with a commitment to sincerely
implement and practice house keeping.
Problems cannot be clearly seen when
the work place is unorganized. Cleaning and
organizing the workplace
helps
the
team
to
uncover
problems.
Making
problems
visible
is
the
first
step
of
improvement.
5s
is
a
foundation
program before the implementation of TPM, hence in
the above figure, 5s has been positioned in
the base.
If this 5S is not
taken up seriously, then it leads to 5D. They
are
Delays, Defects,
Dissatisfied
customers, declining
profits and Demoralized employees.
Following are
the
pillars of 5S.
8
Japanese
Term
English
Translation
Equivalent
term
'S'
Seiri
Organisation
Sort
Seiton
Tidiness
Systematise
Seiso
Cleaning
Sweep
Seiketsu
Standardisation
Standardise
Shitsuke
Discipline
Self - Discipline
SEIRI - Sort out:
This means sorting and
organizing the items as critical, important,
frequently used items, useless, or
items that are not need as of now.
Unwanted items can be salvaged. Critical items
should be kept for use
nearby and items
that are not be used in near future, should be
stored in some place.
For this step,
the worth
of the item should
be decided based on utility and not
cost
. As a result of this step, the
search time is
reduced.
Priority
Frequency of
Use
How to
use
9
Low
Average
High
Less than
once per year, Once per
year<
Throw away,
Store away from the
workplace
At least 2/6 months, Once
per month,
Store together but
offline
Once per
week
Once Per
Day
Locate at
the workplace
SEITON -
Organise:
The
concept here is that
Each items has a
place, and only one
place
back after usage at the
same place. To identify items easily, name plates
and coloured tags has to be used.
Vertical racks can be used for this
purpose, and heavy items occupy the bottom
position in the racks.
SEISO - Shine the workplace:
This involves cleaning the
work place free of burrs, grease, oil, waste,
scrap etc. No loosely hanging
wires or
oil leakage from machines.
SEIKETSU - Standardization:
Employees has to discuss
together and decide on standards for keeping the
work place / Machines /
pathways neat
and clean. This standards are implemented for
whole organization and are tested / Inspected
randomly.
SHITSUKE - Self discipline:
Considering
5S
as
a
way
of
life
and
bring
about
self-
discipline
among
the
employees
of
the
organization.
This
includes
wearing
badges,
following
work
procedures,
punctuality,
dedication
to
the
organization etc.
This
5S
implementation
has to
be
carried out
in
phased
manner.
First
the current
situation of the
workplace
has to be studied by conducting a 5S audit. This
audit uses check sheets to evaluate the current
situation. This check sheet consists of
various parameters to be rated say on a 5-point
basis for each 'S'. The
ratings give
the current situation. The each of the above-
mentioned 5S is implemented and audit is conducted
at regular intervals to monitor the
progress and evaluate the success of
implementation. After the completion
of
implementation
of
5S
random
audits
could
be
conducted
using
these
check
sheets
to
ensure
that
it
is
observed in true spirits by every one
in the work place. A sample check sheet is shown
below. The check
sheet
shown
below takes a
general
industry into consideration.
It
may
vary from
even
from
one plant to
another, and more exhaustive. The
points shown below could be used as rough
guidelines.
1-S
SEIRI (Sorting
out)
Score on
5
point basis
10
Floor area of the hangar is free of
unwanted items.
Tops and
inside of all the cupboards, shelves, tables,
drawers are free of unwanted
items.
Rules for disposal and detecting non
moving stocks are adhered to
?
Red
labelling done.
?
Disposal standards
maintained
?
Regular clearing of all storage areas
?
Regular removal of
garbage and waste bins
Items
are stored according to frequency of
use.
Notice boards are free
of old notices.
SEITON (Set
in order)
All gangways are
specified and clearly marked and machines have
identification
labels.
All equipments / tools / files /
cupboards etc are arranged. Cup boards have
index
list pasted in the
door.
Parking areas are
specified and marked for vehicles, pallets,
trolleys, garbage bens
etc.
Colour coding is effectively used for
easy identification wherever necessary.
SEISO (Shine)
All
equipments, tools, accessories, furniture are
maintained at high level of
cleanliness, maintenance schedules are
displayed and followed.
Floors walls windows are maintained at
high level of cleanliness.
There no oil spillage or dust in the
work area.
There is general
appearance of cleanliness all around.
2-S
3-S
4-S
SEIKETSU
(Standardization)
All aisles
/ gangways have a standard size and colour. All
labels and notices are
standardized.
Standards procedures related to are
followed.
Periodic disposal
of waste organized.
Fire
extinguisher type, validation, position in order.
First aid kit fully equipped.
Standard visual management viz.,
warning signs, labelling for
correct
identification,
colour coding checklists etc are followed and
maintained
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