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.

• Avoid wastage in a quickly changing economic environment.

• Producing goods without reducing product quality.

• Reduce cost.

• Produce a low batch quantity at the earliest possible time.

• Goods send to the customers must be non defective.

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

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 is summarized below.

Types of maintenance:

1. Breakdown maintenance:

            It means that people waits until equipment fails and repair it.  Such a thing could be used when the equipment failure does not significantly affect the operation or production or generate any significant loss other than repair cost.

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.  

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.      

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

4. Maintenance prevention ( 1960 ):

            It indicates the design of a new equipment.  Weakness of current machines are sufficiently studied (on site information leading to failure prevention, easier maintenance and prevents of defects, safety and ease of manufacturing ) and is incorporated before commissioning a new equipment

The Evolution of TPM:

            TPM is a 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 routine maintenance of equipment would be carried out by the operators.  ( 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 was released of their routine maintenance task and they carried out equipment modification for improving reliability and maintainability.  The modifications were made or incorporated in new equipment.  These task are aimed at maintenance prevention (MP).  Thus preventive maintenance along with Maintenance prevention and Maintainability Improvement gave birth to Productive maintenance (PM).  The aim of productive maintenance was to maximize plant and equipment effectiveness to achieve optimum life cycle cost of production equipment.

            By then Nippondenso 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.

TPM Targets:

    P    
                Obtain Minimum 80% OPE.
                Obtain Minimum 90% OEE ( Overall Equipment Effectiveness )
                Run the machines even during lunch.  ( Lunch is for operators and not for machines ! )

    Q   
                Operate in a manner, so that there are no customer complaints.

    C       
                Reduce the manufacturing cost by 30%.
    D   
                Achieve 100% success in delivering the goods as required by the customer.

    S            
                Maintain a accident free environment.

    M   
                Increase the suggestions by 3 times.  Develop Multi-skilled and flexible workers.

OPE (Overall Plant Efficiency):

            It is a function of three factors namely Management losses, Scheduled downtime loss and OEE (discussed in detail in the subsequent paragraph).  Management losses include losses due to want of tools, want of raw materials, want of trays, want of men etc.  Scheduled downtime includes any JH activity, Preventive maintenance activity or meetings.

OEE ( Overall Equipment Efficiency ):

            The basic measure associated with Total Productive Maintenance (TPM) is the OEE.  This OEE highlights the actual "Hidden capacity" in a organization.  OEE is 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 a 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:

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.  In terms of quality rate, there are two theories of accounting for product defects. The first theory contends that quality defects upstream of the constraining machine affect the output of the line or process only if they starve the constraining machine for material. Quality defects at or downstream of the constraining machine do affect the potential output of the line or process and should be counted against the quality rate.

            Quality experts and the “concept of zero” state that any quality defect is unacceptable and we should attempt to penalize our performance indicators for all quality defects whether they are upstream or downstream of the constraining machine.  This concept is valid, but some quality defects do cost more than others. When resources are limited, more severe quality issues should be addressed before those of less severity.  Quality issues downstream of the constraining machine are more severe than those upstream and therefore should be of higher priority.  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 figured for a critical piece of equipment is shown below.

• 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.

Example of OEE calculation
        Given below is the details that contain shift data to be used for a complete OEE calculation (Including calculation of the three contributing factors of availability, performance, and quality)

1. Planned production time = Shift length – breaks = 480 – 15 – 15 – 30 = 420 Minutes

2. Operating time = Planned production time – Downtime = 420 – 50 = 370 Minutes

3. Good pieces = Pieces produced – Reject pieces = 20,225 – 503 = 19,722 Pieces

4. Availability = Operating time / Planned production time = 370 Minutes / 420 Minutes = 0.881 (88.1%)

5. Performance (Speed) = Pieces produced / (Ideal rate x Operating time) = 20,225 / 70 x 370 = 0.781 (78.1%)

6. Quality = Good pieces / Pieces = 19,722 / 20,225 = 0.975 (97.5%)

7. OEE = Availability x Performance x Quality = 0.881 x 0.781 x 0.975 = 0.671 (67.1%)

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Steps in introduction of TPM in a organization

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 to all.  Publish it in the house magazine and put it in the notice board.  Send a letter to all concerned individuals.

STEP 2 - Initial education and propaganda for TPM:

            Training is to be done based on the need. Some need intensive training and some just an awareness. Take people who matters to places where TPM already successfully implemented.

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:

            Now each area is benchmarked and fix up a target for achievement.

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

            This is a ceremony and we should invite all. Suppliers as they should know that we want quality supply from them. Related companies and affiliated companies who can be our customers, sisters concerns etc. Some may learn from us and some can help us and customers will get the communication from us that we care for quality output.

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 all there activities one would has reached maturity stage. Now is the time for applying for PM award. Also think of challenging level to which you can take this movement.

Organization Structure for TPM Implementation :

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Pillars of TPM

PILLAR 1 - 5S:

            TPM starts with 5S.  It is a systematic process of house keeping 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.  If this 5S is not taken up seriously, then it leads to 5D.  They are Delays, Defects, Dissatisfied customers, Declining profits and Demoralized employees.

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.

SEITON - Organize:

            The concept here is that "Each items has a place, and only one place".  The items should be placed back after usage at the same place.  To identify items easily, name plates and colored tags has to be used.  Vertical racks can be used for this purpose, and heavy items occupy the bottom position in the racks.  The aim is to arrange items, so that it is in easy reach.

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.

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PILLAR 2 - JISHU HOZEN ( Autonomous maintenance ):

            This pillar is geared towards developing operators to be able to take care of small maintenance tasks, thus freeing up the skilled maintenance people to spend time on more value added activity and technical repairs. The operators are responsible for upkeep of their equipment to prevent it from deteriorating. 

Policy:

1. Uninterrupted operation of equipments.

2. Flexible operators to operate and maintain other equipments.

3. Eliminating the defects at source through active employee participation.

4. Focus on Kaizen and small group activities

5. Stepwise implementation of JH activities.

JISHU HOZEN Targets:

1. Prevent the occurrence of 1A / 1B because of JH.

2. Reduce oil consumption by 50%

3. Reduce process time by 50%

4. Increase use of JH by 50% (Lubrication / coolant / hydraulic)

Steps in JISHU HOZEN:

1. Preparation of employees.

2. Initial cleanup of machines.

3. Take counter measures

4. Fix tentative JH standards

5. General inspection

6. Autonomous inspection

7. Standardization and

8. Autonomous management.

            Each of the above mentioned steps is discussed in detail below.

1. Train the Employees :

            Educate the employees about TPM, Its advantages, JH advantages and Steps in JH.  Educate the employees about abnormalities in equipments.

2. Initial cleanup of machines :

• Supervisor and technician should discuss and set a date for implementing step1

• Arrange all items needed for cleaning

• On the arranged date, employees should clean the equipment completely with the help of maintenance department.

• Dust, stains, oils and grease has to be removed.

• Following are the things that has to be taken care while cleaning.  They are Oil leakage, loose wires, unfastened nits and bolts and worn out parts.

• After clean up problems are categorized and suitably tagged.  White tags is place where problems can be solved by operators.  Pink tag is placed where the aid of maintenance department is needed.

• Contents of tag is transferred to a register.

• Make note of area which were inaccessible.

• Finally close the open parts of the machine and run the machine.

3. Counter Measures :

• Inaccessible regions had to be reached easily.  E.g. If there are many screw to open a fly wheel door, hinge door can be used.  Instead of opening a door for inspecting the machine, acrylic sheets (It is transparent) can be used.

• To prevent work out of machine parts necessary action must be taken.

• Machine parts should be modified to prevent accumulation of dirt and dust.

4. Tentative Standard :

• JH schedule has to be made and followed strictly.

• Schedule should be made regarding cleaning, inspection and lubrication and it also should include details like when, what and how.

5. General Inspection:

• The employees are trained in disciplines like Pneumatics, electrical, hydraulics, lubricant and coolant, drives, bolts, nuts and Safety.

• This is necessary to improve the technical skills of employees and to use inspection manuals correctly.

• After acquiring this new knowledge the employees should share this with others.

• By acquiring this new technical knowledge, the operators are now well aware of machine parts.

6. Autonomous Inspection:

Loss	Category
Failure losses - Breakdown loss Setup / adjustment losses Cutting blade loss Start up loss Minor stoppage / Idling loss. Speed loss - operating at low speeds. Defect / rework loss Scheduled downtime loss	Losses that impede equipment efficiency
Management loss Operating motion loss Line organization loss Logistic loss Measurement and adjustment loss	Loses that impede human work efficiency
Energy loss Die, jig and tool breakage loss Yield loss.	Loses that impede effective use of production resources.

Aspect	Sporadic Loss	Chronic Loss
Causation	Causes for this failure can be easily traced.  Cause-effect relationship is simple to trace.	This loss cannot be easily identified and solved.  Even if various counter measures are applied
Remedy	Easy to establish a remedial measure	This is caused  by hidden defects in machine, equipment and methods.
Impact / Loss	A single loss can be costly	A single cause is rare - a combination of causes trends to be a rule
Frequency of occurrence	The frequency of occurrence is low and occasional.	The frequency of loss is more.
Type of analysis required	Why-Why analysis.  Here the question 'Why' is queried against the problem for five times, within which the solution is reached	Intricate and complex method required.  This includes cause and effect analysis and correlation analysis.
Corrective action	Usually the line personnel in the production can attend to this problem.	Specialists in process engineering, quality assurance and maintenance people are required.