Total productive maintenance (TPM) is a series of methods that ensures every piece of equipment in a production process is always able to perform its required tasks so that production is never interrupted. It is a comprehensive, team-based, continuous activity that enhances normal equipment-maintenance activities and involves every worker. TPM helps you focus on and accelerate the equipment improvements required for you to implement methods such as one-piece flow, quick changeover, and load leveling as part of your company’s lean initiative. TPM also helps to improve your first-time through, or FTT , quality levels. It also helps in
- Improved equipment performance. Equipment operators and maintenance workers prevent poor performance by conducting maintenance inspections and preventive maintenance activities. They also capture information about poor machine performance, enabling teams to diagnose declining performance and their causes. By preventing and eliminating these causes, these employees can improve performance efficiency.
- Increased equipment availability. TPM enables operators and maintenance workers alike to help prevent equipment failures by performing maintenance inspections and preventive maintenance activities. These employees also capture information regarding machine downtime, enabling your improvement team to diagnose failures and their causes. When you are able to prevent and eliminate the causes of failures, your asset availability improves.
- Increased equipment FTT quality levels. Process parameters that have a direct effect on product quality are called key control characteristics. For example, if a thermocouple in a furnace fails and an incorrect measurement is sent to the heating elements, this causes temperatures to fluctuate, which might significantly affect product quality. The goal of a TPM program is to identify these key control characteristics and the appropriate maintenance plan to ensure prevention of a failure of performance degradation.
- Reduced emergency downtime and less need for “firefighting” (i.e., work that must be done in response to an emergency).
- An increased return on investment, or ROI , in equipment.
- Increased employee skill levels and knowledge.
- Increased employee empowerment, job satisfaction, and safety.
Types of maintenance:
- 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.
- Preventive maintenance:
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.
- 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.
- 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 in colour indicates the deteriorating condition of the oil. As this is a condition-based maintenance, the oil or coolant is replaced.
- Periodic maintenance (Time based maintenance – TBM):
- Corrective maintenance:
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.
- Maintenance prevention:
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.
What is Total Productive Maintenance (TPM)?
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.Each letter in the acronym of TPM is subtle yet critical.
- Total implies a comprehensive look at all activities that relate to maintenance of equipment and the impact each has upon availability.
- Productive relates to the end goal of the effort i.e. efficient production not merely efficient maintenance as is often mistakenly assumed.
- Maintenance signifies the directional thrust of the program in ensuring reliable processes and maintaining production.
Operational availability has long been recognized as critical in many process intensive industries. Oil drilling petroleum companies, airlines, chemical process plants, for example and many other asset intensive industries simply can not afford to have any down time. Each minute an oil well is down represents lost barrels of output and a tremendous amount of foregone revenue to the parent company. Airlines also can not afford any downtime for obvious reasons of passenger safety as well as revenue. It is not surprising therefore that these industries are often the benchmarks in terms of operational availability although it is often accomplished via extensive redundant systems as well as excellence in maintenance methods. Other companies however, should also examine the benefits of TPM as well for additional reasons. First TPM is critical as a precondition for many elements of lean manufacturing to flourish and secondly there are financial benefits as well.
There are four key points regarding TPM implementation. These points are critical for long term success of the program. These points include a total life cycle approach, total pursuit of production efficiency, total participation, and a total systems approach.
- Total life cycle approach
A total life cycle approach recognizes that much like humans equipment requires different levels of resources and types of attention during the life cycle. During production start up is when initial trouble is most likely to occur and significant time is spent debugging equipment and learning to fix and maintain processes. This learning process is started long before the equipment ever reaches the production floor by extensively researching previous processes and continuing what worked well and improving weak points in the machine design. After machine installation different maintenance techniques is employed in order to efficiently maintain production. As a last resort breakdown maintenance (BM) is employed when all else fails until the root cause is thoroughly identified and the problem can be prevented from recurring. During most of the equipment life cycle time, frequency, or condition based preventive maintenance (PM) methods are employed to stop problems before they occur. PM intervals and contents are adjusted as experience is gained about the equipment over the life cycle. Daily maintenance (DM) is practiced by the operators of the equipment. Occasionally equipment reliability problems result that require the time and attention of the original equipment manufacturer or specialists to resolve. In these instances involving changes to fixtures, jigs, tooling, etc. corrective maintenance (CM) is practiced and fundamental improvements to the design of the process are implemented. Lastly, all processes are studied at length over the entire life cycle to see where time, spare parts, and money are being consumed. When future equipment is ordered a list of required improvements are identified for the vendor and analyzed jointly in terms of maintenance prevention (MP) activities.
- Total pursuit of production efficiency
Total pursuit of production efficiency relates to the goal of eliminating all the aforementioned six types of production losses associated with a piece of equipment. Different situations and types of equipment require different improvement activities. For example during the 1950’s the primary source of production loss in a stamping department was the changeover process from one stamping die to another. Frequently this change over from one die to the next might require anywhere from one to two shifts. Over time however, by studying the changeover and identifying the waste in the process teams were able to improve this loss downward over a ten years period to a few minutes at worst. In some cases the changeover can now be done in seconds. Today in other processes such as machining lines the predominant equipment loss is machine breakdown time and minor stops which are often hard to identify.
- Total participation
The total participation aspect of TPM is often much trumpeted by consultants and displayed in articles as a team based event where a single piece of equipment is cleaned and checked from top to bottom to improve availability. The projects are noble and excellent learning activities. They should not be mistaken however as the primary way to implement participation.
- Total systems approach
Like a chain composed of multiple links the total strength of the system is only as good as the weakest link in the chain. Constant effort and management attention is placed upon improving the described aspects of the equipment life cycle, pursuit of efficiency, and participation by all in accordance with their responsibilities. A total systems approach also means effectively linking and improving all support activities such as employee training and development, spare parts and documentation management, maintenance data collection and analysis, and feedback with equipment vendors.
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.
- 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
|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 “I (Production operators) Operate, You (Maintenance department) fix” is not followed.
|Direct benefits of TPM
|Indirect benefits of TPM
TPM Basic Concepts And Structures:
TPM is defined as “Total Productive Manufacturing is a structured equipment-centric continuous improvement process that strives to optimize production effectiveness by identifying and eliminating equipment and production efficiency losses throughout the production system life cycle through active team-based participation of employees across all levels of the operational hierarchy.” The key elements of TPM is :
- Structured Continuous Improvement Process.
- Optimized Equipment (Production) Effectiveness.
- Team-based Improvement Activity.
- Participation of employees across all levels of the operational hierarchy
One of the most significant elements of the structured TPM implementation process is that it is a consistent and repeatable methodology for continuous improvement.
OEE (Overall Equipment Efficiency):
The basic measure associated with Total Productive Maintenance (TPM) is the OEE. This OEE highlights the actual “Hidden capacity” in an 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.
- Availability or uptime (downtime: planned and unplanned, tool change, tool service, job change etc.)
- Performance efficiency (actual vs. design capacity)
- Rate of quality output (Defects and rework)
Overall Equipment Effectiveness Model
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:
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 = (No of products processed – No of products rejected) (Number of products processed)
A simple example on how OEE is calculated 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.
The Pillars of TPM
The principal activities of TPM are organized as ‘pillars’. Depending on the author, the naming and number of the pillars may differ slightly, however, the generally accepted model is based on Nakajima’s eight pillars
Focused Improvement Pillar (Kobetsu Kaizen)
Focused improvement includes all activities that maximize the overall effectiveness of equipment, processes, and plants through uncompromising elimination of losses and improvement of performance.Losses may be either a function loss (inability of an equipment to execute a required function) or a function reduction (reduced capability without complete loss of a required function). The objective of Focused Improvement is for equipment to perform as well every day as it does on its best day. The fact is machines do virtually 100 percent of the product manufacturing work. The only thing we people do, whether we’re operators, technicians, engineers, or managers, is to tend to the needs of the machines in one way or another. The better our machines run, the more productive our shop floor, and the more successful our business. The driving concept behind Focused Improvement is Zero Losses. Maximizing equipment effectiveness requires the complete elimination of failures, defects, and other negative phenomena – in other words, the wastes and losses incurred in equipment operation.
Leflar identifies a critical TPM paradigm shift that is the core belief of Focused Improvement.
- Old Paradigm – New equipment is the best it will ever be.
- New Paradigm – New equipment is the worst it will ever be.
“The more we operate and maintain a piece of equipment, the more we learn about it. We use this knowledge to continuously improve our maintenance plan and the productivity of the machine. We would only choose to replace a machine should its technology become obsolete, not because it has deteriorated into a poorly performing machine.”
Focused Improvement methodologies have led to short-term and long-term improvements in equipment capacity, equipment availability, and production cycle time. Focused Improvement has been, and still is, the primary methodology for productivity improvement.Overall Equipment Effectiveness (OEE) is the key metric of Focused Improvement. Focused Improvement is characterized by a drive for Zero Losses,meaning a continuous improvement effort to eliminate any effectiveness loss. Equipment losses may be either chronic (the recurring gap between the equipment’s actual effectiveness and its optimal value) or sporadic (the sudden or unusual variation or increase in efficiency loss beyond the typical and expected range).
The loss causal factors may be,
- Single – a single causal factor for the effectiveness loss.
- Multiple – two or more causal factors combined result in the effectiveness loss.
- Complex – the interaction between two or more causal factors results in the effectiveness loss.
Focused Improvement includes three basic improvement activities. First, the equipment is restored to its optimal condition. Then equipment productivity loss modes (causal factors) are determined and eliminated. The learning that takes place during restoration and loss elimination then provide the TPM program a definition of optimal equipment condition that will be maintained (and improved) through the life of the equipment. Equipment restoration is a critical first step in Focused Improvement, maintaining basic equipment conditions is a maintenance practice that is ignored in most companies today. When the maintenance group gets occupied with capacity loss breakdowns and trying to keep the equipment running properly, basic tasks like cleaning, lubricating, adjusting, and tightening are neglected. Equipment failure is eliminated by exposing and eliminating hidden defects (fuguai). The critical steps to eliminate equipment restoration is to expose the hidden defects, deliberately interrupt equipment operation prior to breakdown, and to resolve minor defects promptly. The first aim of attaching importance to minor defects is to ‘cut off synergic effects do to the accumulation of minor defects’. Even though a single minor defect may have a negligible impact on equipment performance, multiple minor defects may stimulate another factor, combine with another factor, or may cause chain reactions with other factors. The elimination of minor defects should be one of the highest priorities of continuous improvement. It is important to realize that even in large equipment units or large-scale production lines, overall improvement comes as an accumulation of improvements designed to eliminate slight defects. So instead of ignoring them, factories should make slight defects their primary focus. Minor Defects are the root cause of many equipment failures and must be completely eliminated from all equipment.Machines with minor defects will always find new ways to fail. Minor or hidden defects result from a number of causal factors such as:
- Physical Reasons.
- Contamination (dust, dirt, chemical leaks, etc.).
- Not visible to the operator.
- Excessive safety covers.
- Equipment not designed for ease of inspection.
- Operator Reasons.
- Importance of visible defects not understood.
- Visible defects not recognized.
Tracking OEE provides a relative monitor of equipment productivity and the impact of improvement efforts. Understanding efficiency losses drives the improvement effort.Typically, productivity losses are determined through analysis of equipment and production performance histories. The impact of productivity losses should be analyzed from two perspectives;
- The frequency of loss (the number of occurrences during the time
- The impact of the loss (the number lost hours, lost revenue, cost, etc.).
Companies differ in their approaches to systematic improvement, but all incorporate roughly the same basic elements: planning, implementing, and checking results. A number of tools are commonly used to analyze productivity losses in the Focused Improvement pillar.
- Pareto Charts.
- 5-Why Analysis.
- Fishbone Diagrams.
- P-M Analysis.
- Fault Tree Analysis (FTA).
- Failure Mode and Effects Analysis (FMEA).
It is important to note that Focused Improvement and equipment restoration is not a one-time activity. Usage results in wear and potential deterioration. Restoring normal equipment wear is a process that continues for the entire life of the equipment.
Autonomous Maintenance Pillar (Jishu Hozen):
Autonomous maintenance is the process by which equipment operators accept and share responsibility (with maintenance) for the performance and health of their equipment. The driving concept of Autonomous Maintenance (AM) is the creation of ‘expert equipment operators’ for the purpose of ‘protecting their own equipment’.The paradigm shift that AM addresses is a transition in the operator perception from ‘I run the equipment, Maintenance fixes it’, to ‘I own the performance of this equipment’. In this Autonomous Maintenance environment, The greatest requirements for operators are, first, to have the ability to ‘detect abnormalities’ with regard to quality or equipment, based on a feeling that ‘there is something wrong’.Autonomous Maintenance is closely linked with Focused Improvement in that both TPM pillars support equipment restoration and sustaining basic equipment conditions. Through autonomous activities – in which the operator is involved in daily inspection and cleaning of his or her equipment – companies will discover the most important asset in achieving continuous improvement – its people.Autonomous Maintenance has two aims,
- To foster the development and knowledge of the equipment operators, and
- To establish an orderly shop floor, where the operator may detect departure from optimal conditions easily.
Autonomous Maintenance offers a significant departure from Taylorism where operators are required to repeat simple structured work tasks with little understanding and knowledge about the equipment they run or the products they manufacture. Autonomous Maintenance involves the participation of each and every operator, each maintaining his own equipment and conducting activities to keep it in the proper condition and running correctly. It is the most basic of the eight pillars of TPM. If autonomous maintenance activities are insufficient, the expected results will not materialize even if the other pillars of TPM are upheld. Autonomous Maintenance empowers (and requires) equipment operators to become knowledgeable managers of their production activities, able to:
- Detect signs of productivity losses.
- Discover indications of abnormalities (fuguai).
- Act on those discoveries.
JIPM(Japan Institute of Plant Maintenance ) describes the critical operator Autonomous Maintenance skills to be:
- Ability to discover abnormalities.
- Ability to correct abnormalities and restore equipment functioning.
- Ability to set optimal equipment conditions.
- Ability to maintain optimal conditions.
The operator skill levels required to support Autonomous Maintenance can be defined as:
Recognize deterioration and improve equipment to prevent it.
Understand equipment structure and functions.
Understand causes of equipment-induced quality defects.
|Level 4||Perform routine repair on equipment.
The specific goals of Autonomous Maintenance include:
- Prevent equipment deterioration through correct operation and daily inspections.
- Bring equipment to its ideal state through restoration and proper
- Establish the basic conditions needed to keep equipment well maintained.
Four significant elements of the Autonomous Maintenance effort are
- Initial Clean,
- Manager’s Model and Pilot Teams.
- Visual Controls and One Point Lessons.
Cleaning equipment is typically the first phase in Autonomous Maintenance. Known as the Initial Clean within the AM program, this really means inspection of equipment. The philosophy being that in the process of cleaning the operator discovers fuguai. From the TPM perspective, cleaning is aimed at exposing and eliminating hidden defects. Prior to starting the Initial Clean process, the team should receive training in equipment operation and safety precautions so that the Initial Clean can proceed at no risk to the equipment or the team members. The TPM Initial Clean is part of the early TPM training and is performed by a small team that includes the operator responsible for the area, maintenance personnel who work on the tool, the area production supervisor, and others with a vested interest in performance of the production area. A qualified TPM trainer should act as facilitator for the Initial Clean activity. Seven types of abnormalities that should be the focus of the Initial Clean activity.
Type of Abnormality Abnormality Examples Minor Flaws Contamination Dust, dirt, powder, grease, rust, paint Damage Cracking, crushing, deformation, chipping, Play Shaking, falling out, tilting, eccentricity, wear, distortion, corrosion Slackness Belts, chains Abnormal phenomena Unusual noise, overheating, vibration, strange smells, discoloration, incorrect pressure or other parameter Adhesion Blocking, hardening, accumulation of debris, peeling, malfunction Unfulfilled Basic Conditions Lubrication Insufficient, dirty, unidentified, unsuitable, leaking Lubrication supply Dirty, damaged, deformed inlets, faulty lubricant pipes Oil level gauges Dirty, damaged, leaking, no indication of correct level Tightening Nuts and bolts – slackness, missing, cross threaded, too long, crushed, corroded, washer unsuitable, backwards Inaccessible Places Cleaning Machine construction, covers, layout, footholds, access space Checking Covers, construction, layout, instrument position and orientation, operating-range display Lubricating Position of lubricant inlet, construction, height, footholds, lubricant outlet, space Operation Machine layout, position of valves/switches/levers, footholds Adjustment Position of pressure gauges/thermometers/flow meters/etc. Contamination Sources Product Leaks, spills, spurts, scatter, overflow Raw materials Leaks, spills, spurts, scatter, overflow Lubricants Leaking, split, seeping Gases Leaking Liquids Leaking, split, spurting Scrap Flashes, cuttings, packaging materials, scrap/rework product Other Contaminants brought in by people/equipment Quality Defect Sources Foreign matter Inclusion, infiltration, entrainment Shock Dropping, jolting, collision, vibration Moisture Control (too little/too much), infiltration, defective elimination Filtration Abnormalities in filter mechanisms Unnecessary and Non-Urgent items Machinery Excessive or unused Piping Pipes, hoses, ducts, valves, etc Measurement instruments Temperature, pressure, vacuum, etc. Electrical Equipment Wiring, switches, plugs, etc. Jigs and tooling General tools, jigs, molds, dies, frames, etc. Spare parts Equipment spares, process spares, etc. Repairs in progress Components and maintenance tooling Unsafe Places Floors Uneven, projections, cracking, peeling, wear Steps Too steep, irregular, pealing, corrosion, missing handrails Lights Dim, out of position, dirty, broken covers Rotating machinery Displaced, broken/missing covers, no emergency stops Lifting gear Hooks, brakes, cranes, hoists Others Special/dangerous substances, danger signs, protective clothing/gear
The purpose of the Initial Clean is threefold.
- Small Work Groups (also known as Small Group Activity- SGA) are able to join together to accomplish a common goal, the cleaning of a particular equipment or area.
- Promote a better understanding of, and familiarity with, the equipment or process area.
- Uncover hidden defects that, when corrected, have a positive effect on equipment performance.
Manager’s Model and Pilot Teams:
A common approach to proliferating Autonomous Maintenance is through the Manager’s Model and Pilot Teams. The Manager’s Model and Pilot Teams develop individual Autonomous Maintenance skills, train leaders for Autonomous Maintenance teams, and demonstrate the effectiveness of Autonomous Maintenance implementation, and refine the Autonomous Maintenance implementation process.
The objectives for the Manager’s Model are:
- Change employee attitudes (foster positive attitudes) about TPM.
- Demonstrate the power of TPM implementation.
- Prove and improve the TPM implementation process.
- Show the results of effective teamwork.
- Test the water – experiment with TPM methodologies.
- Identify and address initial barriers to TPM implementation.
- Build the local TPM policies and procedures.
- Plan further TPM rollout and supporting infrastructure.
- Take academic TPM and turn it into results.
- Customize TPM activities to fit the organization.
- Prove that TPM can be implemented successfully.
- Develop and provide tools, procedures, and infrastructure for further TPM activity.
Continuous learning is the heart of continuous improvement. Machines do only what people make them do – right or wrong – and can only perform better if people acquire new knowledge and skills regarding equipment care. The proliferation of Autonomous Maintenance can be viewed as a series of cascading activities starting with the Manager’s Model
The key to the establishment and development of the basic TPM plan is ensuring the support of the plan’s priorities and activities by the top management who drive it forward. The most important point is how well the top and middle managers recognize the necessity for and future value of TPM activities. During the Manager’s Model, the site management team engages in an Autonomous Maintenance project. Managers trained during the Manager’s Model become the leaders of the subsequent Autonomous Maintenance Pilot Teams that continue Autonomous Maintenance proliferation in specific work areas. Depending on the size of the operation, there may be a number of Pilot Teams operating within a work area. Many times a company will embark on a TPM journey to have it fail because it was not supported at a high enough organizational level or management failed to follow the manager’s model of experiential tops down management involvement and participation. Likewise, the Pilot Teams spawn work area Autonomous Maintenance teams and provide training and experience for the leaders of those teams. Candidate equipment for Manager’s Model and Pilot Team Autonomous Maintenance deployment should be selected with the following criteria in mind.
- The equipment and the results of the AM activity are visible to the employees.
- There is a high probability that AM activity will improve the performance of the equipment and the improvement will be meaningful to the operation.
- Improving equipment performance through AM activity presents sufficient challenge to validate the Autonomous Maintenance improvement process.
Visual controls can be defined as visual or automated methods which indicate deviation from optimal conditions, indicate what to do next, display critical performance metrics, or control the movement and/or location of product or operation supplies. Visual controls present to the manufacturing operator;
- WHAT the user needs to know.
- WHEN the user needs to know it.
- WHERE the user needs to see it.
- In a format that is CLEARLY UNDERSTOOD by the user.
Visual controls are varied and may be specific to a particular production environment. Some examples of visual controls include the following.
- Graphic Visual Controls. Gauges and meters.
- Kanban systems.
- Slip marks.
- Storage or location identification.
- Audio Visual Controls.
- Alarms (sirens, buzzers, etc.).
- Verbal (commands, warnings, etc.).
- Automated Visual Controls.
- Closed-loop automation (detect and respond).
Activity boards are a specific type of visual control that is commonly utilized in TPM. JIPM refers to activity boards as a guide to action. They present the TPM team with “a visual guide to its activities that makes the improvement activities so clear that anyone can immediately understand them. JIPM suggests that the activity board include the following components.
- Team name, team members, and team roles (pictures).
- Company policy and/or vision.
- Ongoing results from team activities (charted by month).
- The improvement theme addressed by the team activity. The current problems being solved.
- The current situation and the causes.
- Actions to address the causes and the effects of specific actions (annotated graphs where appropriate).
- Improvement targets.
- Remaining problems or issues for the team.
- Future planned actions.
Activity boards, used as a visual control for Autonomous Maintenance, provide the following functions.
- Visual guide to team improvement activities.
- Scorecard for improvement activity goals and activity effectiveness.
- Translate and present the company vision to employees.
- Encourage, support, and motivate the team members.
- Share learning between improvement teams.
- Celebrate team successes.
Activity boards are posted so that the employees easily access them. They are typically located in the work area or common areas where employees meet.
Another common visual control tool that is used in Autonomous Maintenance is the One Point Lesson. A one point lesson is a 5 to 10-minute self-study lesson drawn up by team members and covering a single aspect of equipment or machine structure, functioning, or method of inspection. Regarding education of operators, in many cases sufficient time cannot be secured for the purpose of education at one time or operators cannot acquire such learning unless it is repeated through daily practice. Therefore, study during daily work, such as during morning meetings or other time, is highly effective. One-point lessons are therefore a learning method frequently used during ‘Jishu-Hozen’ (Autonomous Maintenance) activities. One-point lessons are:
- Tools to convey information related to equipment operation or maintenance knowledge and skills.
- Designed to enhance knowledge and skills in a short period of time (5-10 minutes) at the time they are needed.
- A tool to upgrade the proficiency of the entire team.
The basic principle is for individual members to personally think, study, and prepare a sheet [one-point lesson] with originality and to explain its content to all the other circle members, to hold free discussions on the spot and to make the issue clearer and surer. One-point lessons and are one of the most powerful tools for transferring skills. The teaching technique helps people learn a specific skill or concept in a short period of time through the extensive use of visual images. The skill being taught is typically presented, demonstrated, discussed, reinforced, practiced, and documented in thirty minutes or less. Single-point lessons are especially effective in transferring the technical skills required for a production operator to assume minor maintenance responsibilities. Some key concepts of the one-point lesson are:
- The OPL is visual in nature. Pictures, charts, and graphics are emphasized rather than words.
- The OPL discusses a single topic or action being shared.
- The OPL is developed and researched by the employee doing the work to share learning with other employees doing the work.
- The creating employee at the workstation or during team meetings presents OPL’s.
The significant themes for the effective development and use of one-point lessons are:
- One-point lessons contain a single theme to be learned.
- The information being shared should fit on one page.
- OPL’s contain more visual information than text.
- Any text should be straightforward, easy to understand, and to the point.
- When delivering the OPL, explain the need for the knowledge (what problem is being solved).
- Design OPL’s to be read and understood by the intended audience in 5-10 minutes.
- Those who learn the OPL’s continue to teach others.
- OPLs are delivered at the workstation.
- OPLs are retained for reference.
One-point lessons can share information on basic knowledge (fill in knowledge gaps and ensure people have knowledge needed for daily production), examples of problems (communicate knowledge or skills needed to prevent and resolve problems), or discussion of improvements to equipment or methods (communicate how to prevent or correct equipment abnormalities). After delivery, the one-point lessons become part of the operator training documentation. One-point lessons can also be included as attachments to equipment operating or maintenance specifications.
Planned Maintenance Pillar (PM):
The objective of Planned Maintenance is to establish and maintain optimal equipment and process conditions. Devising a planned maintenance system means raising output (no failures, no defects) and improving the quality of maintenance technicians by increasing plant availability (machine availability). Implementing these activities efficiently can reduce input to maintenance activities and build a fluid integrated system, which includes:
- Regular preventive maintenance to stop failures (Periodic maintenance, predictive maintenance).
- Corrective maintenance and daily MP (maintenance prevention) to lower the risk of failure.
- Breakdown maintenance to restore machines to working order as soon as possible after failure.
- Guidance and assistance in ‘Jishu-Hozen’ (Autonomous Maintenance).
Like Focused Improvement, Planned Maintenance supports the concept of zero failures. “Planned maintenance activities put a priority on the realization of zero failures. The aim of TPM activities is to reinforce corporate structures by eliminating all losses through the attainment of zero defects, zero failures, and zero accidents. Of these, the attainment of zero failures is of the greatest significance, because failures directly lead to defective products and a lower equipment operation ratio, which in turn becomes a major factor for accidents.
- Breakdown Maintenance (BM): Breakdown Maintenance refers to maintenance activity where repair is performed following equipment failure/stoppage or upon a hazardous decline in equipment performance. TPM strives for zero equipment failures, and thus considers any event that requires breakdown maintenance to be a continuous improvement opportunity.
- Time-Based Maintenance: Time-Based Maintenance also known as Periodic Maintenance refers to preventive maintenance activity that is scheduled based on an interval of time (for instance daily, weekly, monthly, etc.) Preventive maintenance keeps equipment functioning by controlling equipment components, assemblies, subassemblies, accessories, attachments, and so on. It also maintains the performance of structural materials and prevents corrosion, fatigue, and other forms of deterioration from weakening them.
- Usage-Based Maintenance: Usage-Based Maintenance refers to preventive maintenance activity that is scheduled based on some measure of equipment usage (for example number of units processed, number of production cycles, operating hours, etc.) Usage-Based Maintenance is significantly different from Time-Based Maintenance in that it is scheduled based on the stress and deterioration that production activity places on equipment rather than just a period of time. Since equipment may run different levels of production from one time period to another, Usage-Based Maintenance allows preventive maintenance to be aligned with the actual workload placed on the equipment.
- Condition-Based Maintenance: Condition-Based Maintenance is a form of preventive maintenance that is scheduled by actual variation or degradation that is measured on the equipment. Condition-Based Maintenance expands on the concept of Usage-Based Maintenance by scheduling maintenance based on observed (or measured) wear, variation, or degradation caused by the stress of production on equipment. Examples of monitored equipment parameters include vibration analysis, ultrasonic inspection, wear particle analysis, infrared thermography, video imaging, water quality analysis, motor-condition analysis, jigs/fixtures/test gauges, and continuous condition monitoring. To execute Condition-Based Maintenance, the user must determine observation points or parameters to be measured that accurately predict impending loss of functionality for equipment. Observations and measurements are taken during scheduled inspection cycles. Visual controls play a role in Condition-Based Maintenance by providing graphic indications for out-of-specification measurements or conditions.
Two types of equipment degradation that should be considered when developing the site Planned Maintenance TPM pillar.
- Graceful Deterioration: Degradation is gradual and the thresholds of acceptable performance can be learned and failures projected within scheduled inspection cycles. Since the deterioration progresses slowly, the pre-failure degradation is identifiable within the scheduled Condition-Based Maintenance inspection cycles.
- Non-graceful Deterioration: Deterioration progresses rapidly (from normal measurement to failure in less than the inspection cycle) and may not be detected within the inspection cycle of Condition-Based Maintenance. Non-graceful deterioration may be learned, which allows the life expectancy of the component or function to be projected. In this case, Calendar-Maintenance Maintenance or Usage- Based Maintenance preventive maintenance scheduling will be effective.
- Predictive Maintenance: Predictive Maintenance takes Condition-Based Maintenance to the next level by providing real-time monitors for equipment parameters (for example voltages, currents, clearances, flows, etc.). The objective of predictive maintenance is to prevent the function of equipment from stopping. This is done by monitoring the function or loss of performance of the parts and units of which equipment is composed, to maintain normal operation. Predictive Maintenance can be considered the ‘crystal ball’ of Planned Maintenance. Predictive Maintenance measures physical parameters against a known engineering limit in order to detect, analyze, and correct equipment problems before capacity reductions or losses occur. The key to the predictive method is finding the physical parameter that will trend the failure of the equipment. Preventive maintenance is then scheduled when a monitored parameter is measured out-of-specification. The flow of predictive maintenance is divided into three broad elements,
- Establishment of diagnostic technologies (monitoring techniques),
- Diagnosis (comparing actual to target readings), and
- Maintenance action (responding to variation).
Where Condition-Based Maintenance occurs as the result of scheduled inspections, Predictive Maintenance identifies variation or degradation as it occurs and initiates maintenance activity.
- Closed-Loop Automation: Simple Closed-Loop Automation describes an advanced automation capability in which equipment performance variation or degradation is monitored real-time and automated corrective input is made to the equipment (when possible within acceptable performance conditions) to adjust for the variation or degradation and continue normal in-specification processing.
Advanced Closed-Loop Automation looks beyond just the equipment performance and monitors production flow as well as equipment, including the following functionality
- Sense changes.
- Execute real-time decision logic acting on all data available to factory automation.
- Work in Progress (WIP).
- Maintenance Repair Operations (MRO).
- Production inventory.
- Resource capacity.
- Issue work directives according to enterprise goals.
- Coordinate equipment and material processing.
- Continuously monitor and report status of equipment, material, and other factory resources.
- Corrective Maintenance: Corrective Maintenance is planned maintenance that makes permanent continuous improvement changes (versus repair activity) to equipment. Within the TPM framework, identification of desirable corrective action activity occurs within the Focused Improvement, Autonomous Maintenance, and Planned Maintenance TPM pillar activity. Corrective Maintenance may reduce/eliminate failure modes, improve variation/degradation identification (visual controls), or simplify scheduled or unscheduled maintenance activity. The key to effective Planned Maintenance is to have a PM plan for every tool. The PM plan is based on the history and analysis of failure modes to determine preventive practices. The PM plan consists of five elements.
- A set of checklists for PM execution.
- A schedule for every PM cycle.
- Specifications and part numbers for every checklist item.
- Procedures for every checklist item.
- Maintenance and parts log (equipment maintenance history) for every machine.
The PM plan is then executed with precision; meaning that is implemented 100% of the time, completed 100% as specified, and implemented without variation by knowledgeable people. The PM plan is continually improved to make it easier, faster, and better. Equipment failures suggest the need for further improvement of the PM plan. To this end, two questions must be answered for every equipment failure post-mortem.
1. Why did we not see the failure coming?
2. Why did the PM plan not prevent the failure?
Maintenance Prevention Pillar (MP)
Maintenance Prevention refers to “design activities carried out during the planning and construction of new equipment, that impart to the equipment high degrees of reliability, maintainability, economy, operability, safety, and flexibility, while considering maintenance information and new technologies, and to thereby reduce maintenance expenses and deterioration losses. Maintenance Prevention is also known as Early Management, Initial
Phase Management or Initial Flow Control. The objective of MP is to minimize the Life Cycle Cost (LCC) of equipment. In TPM, the concept of MP design is expanded to include design that aims at achieving not only no breakdowns (reliability) and easy maintenance (maintainability) but also prevention of all possible losses that may hamper production system effectiveness and pursuit of ultimate system improvement. To be specific, MP design should be so done as to satisfy reliability, maintainability, ‘Jishu-Hozen’, operability, resource saving, safety, and flexibility. Effective Maintenance Prevention supports reduction of the vertical startup lead-time by improving the initial reliability and reducing variability of equipment and processes. In large part, MP improvements are based on learning from the existing equipment and processes within the Focused Improvement, Autonomous Maintenance, and Planned Maintenance TPM pillar activities. MP design activity minimizes future maintenance costs and deterioration losses of new equipment by taking into account (during planning and construction) maintenance data on current equipment and new technology and by designing for high reliability, maintainability, economy, operability, and safety. Ideally, MP-designed equipment must not break down or produce non conforming products…The MP design process improves equipment and process reliability by investigating weaknesses in existing equipment [and processes] and feeding the information back to the designers. One of the goals of MP design is to break free of equipment-centered design mentality by adopting a human-machine system approach. In addition to equipment/process reliability and performance attributes, the systems approach will also look at the man-machine interface as it relates to operability and maintainability and safety.
Quality Maintenance Pillar:
Quality maintenance, in a nutshell, is establishment of conditions that will preclude the occurrence of defects and control of such conditions to reduce defects to zero. Quality Maintenance is achieved by establishing conditions for ‘zero defects’, maintaining conditions within specified standards, inspecting and monitoring conditions to eliminate variation, and executing preventive actions in advance of defects or equipment/process failure. The key concept of Quality Maintenance is that it focuses on preventive action ‘before it happens’ (cause oriented approach) rather than reactive measures ‘after it happens’ (results oriented approach). Quality Maintenance, like Maintenance Prevention, builds on the fundamental learning and structures developed within the Focused Improvement, Autonomous Maintenance, Planned Maintenance, and Maintenance Prevention TPM pillars. Quality Maintenance supports a key objective of TPM – ensuring that equipment and processes are so reliable that they always function properly. The core concept of Quality Maintenance is integrating and executing the structures, practices, and methodologies established within Focused Improvement, Autonomous Maintenance, Planned Maintenance, and Maintenance Prevention. Quality Maintenance occurs during equipment/process planning and design, production technology development, and manufacturing production and maintenance activity. The precondition for implementation of quality maintenance is to put the equipment, jigs, and tools for ensuring high quality in the manufacturing process, as well as processing conditions, human skills, and working methods, into their desired states. Pre-conditions for successful Quality Maintenance implementation include abolishment of accelerated equipment deterioration, elimination of process problems, and the development of skilled and competent users.
Training and Education pillar:
The objective of Training and Education is to create and sustain skilled operators able to effectively execute the practices and methodologies established within the other TPM pillars. The Training and Education pillar establishes the human-systems and structures to execute TPM. Training and Education focuses on establishing appropriate and effective training methods, creating the infrastructure for training, and proliferating the learning and knowledge of the other TPM pillars Training and Education may be the most critical of all TPM pillars for sustaining the TPM program in
the long-term. A test of TPM success is to look at organizational learning, TPM is about continual learning. It is aimed to have multi-skilled revitalized employees whose morale is high and who has eager to come to work and perform all required functions effectively and independently. Education is given to operators to upgrade their skill. It is not sufficient know only “Know-How” by they should also learn “Know-why”. By experience they gain, “Know-How” to overcome a problem what to be done. This they do without knowing the root cause of the problem and why they are doing so. Hence it becomes necessary to train them on knowing “Know-why”. The employees should be trained to achieve the four phases of skill. The goal is to create a factory full of experts. The different phase of skills is
Phase 1: Do not know.
Phase 2: Know the theory but cannot do.
Phase 3: Can do but cannot teach
Phase 4: Can do and also teach.
The objective of Training and Education pillar is
- Achieve and sustain downtime due to want men at zero on critical machines.
- Achieve and sustain zero losses due to lack of knowledge / skills / techniques.
- Aim for 100 % participation in suggestion scheme.
While conducting training and Education Focus should on improvement of knowledge, skills and techniques. Creating a training environment for self-learning based on felt needs. Training curriculum / tools /assessment etc conductive to employee revitalization.Training to remove employee fatigue and make, work enjoyable.
The Steps in Educating and training activities are :
- Setting policies and priorities and checking present status of education and training.
- Establish of training system for operation and maintenance skill up gradation.
- Training the employees for upgrading the operation and maintenance skills.
- Preparation of training calendar.
- Kick-off of the system for training.
- Evaluation of activities and study of future approach.
Administrative TPM Pillar
Administrative TPM applies TPM activities to continuously improve the efficiency and effectiveness of logistic and administrative functions. These logistic and support functions may have a significant impact on the performance of manufacturing production operations. Consistent with the view of a ‘production system’ that includes not only manufacturing, but also manufacturing support functions, TPM must embrace the entire company, including administrative and support departments. Manufacturing is not a stand-alone activity, but is now fully integrated with, and dependent on, its support activities. These departments increase their productivity by documenting administrative systems and reducing waste and loss. They can help raise production-system effectiveness by improving every type of organized activity that supports production. Like equipment effectiveness improvement Administrative TPM focuses on identifying and eliminating effectiveness losses in administrative activities. Implementing Administrative TPM is similar to equipment/process related TPM continuous improvement. The methodologies used in Focused Improvement, Autonomous Maintenance, Planned Maintenance, Maintenance Prevention, and Quality Maintenance are applied to administrative and support tasks and activity. Training and Education, of course, supports Administrative TPM also.
Safety and Environmental Pillar
Although shown as the last pillar of TPM , the TPM Safety and Environmental pillar is equally, if not more, important than the seven others. No TPM program is meaningful without strict focus on safety and environmental concerns. “Ensuring equipment reliability, preventing human error, and eliminating accidents and pollution are the key tenets of TPM. Example of how TPM improves safety and environmental protection is shown here.
- Faulty or unreliable equipment is a source of danger to the operator and the environment. The TPM objective of Zero-failure and Zero-defects directly supports Zero-accidents.
- Autonomous Maintenance teaches equipment operators how to properly operate equipment and maintain a clean and organized workstation. 5-S activity eliminates unsafe conditions in the work area.
- TPM-trained operators have a better understanding of their equipment and processes and are able to quickly detect and resolve abnormalities that might result in unsafe conditions.
- Operation of equipment by unqualified operators is eliminated through effective deployment of TPM.
- Operators accept responsibility for safety and environmental protection at their workstations.
- Safety and environmental protection standards are proliferated and enforces as part of the TPM Quality Maintenance pillar.
Implementing the TPM Safety and Environmental pillar focuses on identifying and eliminating safety and environmental incidents. According to the Heinrich Principle, for every 500,000 safety incidents there are 300 ‘near misses’, 29 injuries, and 1 death. Investigating industrial accidents, Heinrich found that 88% of accidents where caused by unsafe acts of people, 10% where the result of unsafe physical conditions, and 2% he considered ‘acts of God’.
TPM uses Why-Why Analysis to probe for the root causes (incidents in the Heinrich model) that result in safety or environmental near misses.
There are six phases that an operation passes through during an industrial accident.
- Phase 1 – Normal operation, stable state.
- Phase 2 – Signs of abnormality, the system becomes more and more disordered.
- Phase 3 – Unsteady state, difficult to restore to normal.
- Phase 4 – Obvious danger as a result of failure or abnormality. Damage and injury can still be contained and minimized.
- Phase 5 – Injury and severe damage occur.
- Phase 6 – Recovery after the situation is under control.
TPM practices, such as those listed below, allow quick operator intervention and prevent incidents from approaching Phase 3.
- Monitor equipment and processes and quickly correct abnormalities.
- Install and check safety equipment.
- Identify and eliminate hidden equipment abnormalities and defects.
Environmental safety is becoming an increasing point of focus for TPM implementation. Manufacturing management in the 21st century will not be effective if the environmental issues are ignored. Manufacturing management that does not take environmental issues into consideration will be removed from society. One of the causes of environmental issues is that industries, academic institutions, and government agencies have been specialized in research, development, promotion, and diffusion of design technologies to produce more artificial products. There is very little concern about setting conditions for equipment to the most favorable ones after it is put into operation or diagnostic techniques to maintain those conditions. Environmental safety goes beyond simply eliminating accidents. In today’s manufacturing environment, environmental safety includes reduction of energy consumption, elimination of toxic waste, and reduction of raw material consumption. Ichikawa proposes that TPM address the following key environmental objectives within the Safety and Environmental pillar.
- Construct an Environmental Management System (EMS) that integrates environmental issues as a system. This objective is consistent with ISO 14001.
- Implement activities, through the TPM program, to reduce the
environmental impact of manufacturing operations.
- Create systems to reduce the environmental impact of manufacturing product and process development.
- Enhance the environmental awareness and education of all employees.
Ichikawa emphasizes that the Environmental Management System is part and parcel of the work and this implementation should be done through TPM. In concrete terms, this consists of environmental education, products and equipment development that implement improvements for environmental aspects reduction and give consideration to environmental load, and it is considered to be appropriate to develop these themes along the conventional TPM pillars.
Twelve steps TPM Implementation process
|TPM Implementation Phase||TPM Implementation Step||Key Points||Actions|
|Preparation||Formally announce the decision to introduce TPM.||Top management announcement of TPM introduction at formal meeting and through newsletter.||
|Conduct TPM introductory education and publicity campaign.||
|Create a TPM promotion organization.||
|Establish basic TPM policies and goals.||Set baselines and targets.||
|Draft a master plan for implementing TPM.||Draft a master plan for implementing TPM.||
|Introduction||Kick off the TPM initiative.||Master plan from preparation stage to application for TPM prize.||
|Implementation||Establish a system for improving production efficiency.
Focused Improvement Pillar
Autonomous Maintenance Pillar
Planned Maintenance Pillar
Education and Training Pillar
|Establish and deploy the Maintenance Prevention activities.
Maintenance Prevention Pillar
|Develop optimal vertical startup for products, processes, and equipment.||TPM team training.|
|Establish Quality Maintenance systems.
Quality Maintenance Pillar
|Establish, maintain, and control conditions for zero failures, zero defects, zero accidents.||TPM team training.|
|Create systems for eliminating efficiency losses in administrative and logistic functions.
Administrative Maintenance Pillar
|Create the systems for managing health, safety, and the environment.
Safety and Environmental Pillar
|Create systems to ensure zero safety and environmental accidents.||TPM team training.|
|Consolidation and Sustaining||Sustain full TPM implementation and continually improve the TPM process.||
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