17. TOTAL PRODUCTIVEMAINTENANCE (TPM)

KATHLEEN E. McKONEÍ 'iiiversity of Minnesota, Mimieapolis, MN, USA

ELLIOTT N. WEISSUniversity of Virginia. Charlotti'sville. VA. USA

ABSTRACT

Substantial capital investments are required for manufacturing almost allgoods of economic significance. The productivity of these investments en-able companies and nations to compete. The maintenance of capital in-vestments involves significant recurring expenses. For example, in 1991,DuPont's expenditure on company-wide maintenance was roughly equal toits net income. Maintenance expenses vary depending on the type of in-dustry; however, they are typically 15^0% of production costs. Companiesattempt to control maintenance costs by keeping them at a specified budgetlevel, a level often based on the previous year's expenses.

During the last decade, manufacturers found this approach to be insuf-ficient. As companies have invested in programs such as JIT and TQM inan effort to increase organizational capabilities, the benefits from these pro-grams have often been limited by unreliable or inflexible equipment, hi thecontext of JIT & TQM use, rather than being seen simply as an expense thatmust be controlled, maintenance is now regarded as a strategic competitivetool. Total Productive Maintenance (TPM) has evolved as an effective pro-gram for improving equipment performance and increasing organizationalcapabilities.

TPM has resulted in significant improvements in plant performance.McKone, Schoreder, and Cua (1998) evaluated the impact of TPM practices

187

188 VIH. Lean ma nu tac tu ri ne

on manufacturing performance and found that TPM has a positive and sig-nificant relationship with low cost (as measured by high inventory turns),high levels of product quahty (as measured by higher levels of conformanceto specifications), and strong delivery performance (as measured by higherpercentage of on-time deliveries and by faster speeds of delivery). Their re-search indicates that TPM plays a significant role in improving manufacturingperformance.

BACKGROUND

TPM originated from the fields of reliability and maintenance—a pair of closely relateddisciplines that have become standard engineering functions in many industries. Theprimary objective of these functions is to increase equipment availability and overalleffectiveness.

There have been four major periods in the history of maintenance management:

1. The period prior to 1950 was characterized by reactive maintenance. During thisphase little attention was placed on defining reliability requirements or preventingequipment tailures. Typically, equipment specifications included requirements forindividual parts without the consideration of the reUability or availability of theentire system.

2. The second period, which saw the growth of preventive maintenance, involved ananalysis of current equipment to determine the best methods to prevent failure andto reduce repair time. This period resulted from the emergence of the militaryequipment industry during World War II. Emphasis was placed on the economicefficiency of equipnient replacements and repairs as well as on improving equipmentreliability to reduce the mean time between failures.

3. The third period, called productive maintenance, became well established during the1960s when the importance of reliability, maintenance, and economic efficiencyin plant design was recognized. Productive maintenance has three key elements:maintenance prevention, which is introduced during the equipment-design stages;maintainability improvement, which modifies equipment to prevent breakdownsand facilitate ease of maintenance; and preventive maintenance, which includesperiodic inspections and repairs of the equipment. General Electric Corporationis typically credited for initiating productive maintenance in the 1950s but theapproach did not gain popularity until the 1960s (Hartmann, 1992). In the late1950s the concepts of productive maintenance were also promoted in Japan.

4. The most recent period is represented by Total Productive Maintenance (TPM). TPMofficially began in the 1970s in Japan. Seiichi Nakajima, vice-chairman of theJapanese Institute of Plant Engineers (JIPE), the predecessor of the Japan Instituteof Plant Maintenance (jIPM), promoted TPM throughout Japan and has becomeknown as the father of TPM. In 197J, TPM was described byJIPE as follows:

TPM is designed to maximize equipnient effectiveness (improving overall efficiency) byestablishing a comprehensive productive-maintenance system covering the entire life ofthe

._ 1.

17. Total productive maintenance (TPM) 189

equipment, spanning all equipment-related fields (planning, use, maintenance, etc.) and,with the participation of all employees from top management down to shop-floor workers,to promote productive maintenance through motivation management or voluntary small-group activities {Tsuchiya, 1992, 4).

TPM provides a comprehensive conipany-vi'ide approach to maintenance manage-ment.

In the 1980s, TPM was introduced in the United States. There are several reasonswhy American companies are utilizing TPM. Dominant, among other reasons, is thatmany organizations face competitive pressures from firms that have improved plantproductivity, often through successful TPM implementation. One particular group ofcompetitors, the Japanese, have demonstrated in many industries that maintenance isa critical component of their success. JIPM has emphasized the importance of main-tenance and has awarded over 830 preventive-maintenance prizes to companies thathave achieved a high level of success with TPM implementation.

It would, however, be a gross oversimphfication to suggest that the Japanese influ-ence is the only factor that has brought about the popularity of TPM. There are alsoseveral other changes in the manufacturing environment that have increased the im-portance of maintenance. JIT, TQM, and Employee Involvement (EI) programs havebecome more commonplace in industry to address the increasing demands of cus-tomers, companies have attempted to reduce costs, shorten production lead-time, andimprove quality. These improvement programs require rehable and consistent equip-ment throughout the entire plant. Moreover, as customers become more demandingand processes become more interrelated, the need for an effective maintenance strategyalso increases. Figure 1 shows the interrelationships between TPM, JIT, TQM, andEI. From this diagram, it is clear that proper implementation of TPM will enhance theeffectiveness of the other improvement programs. Schonberger (1986) also highlightsthe importance of JIT, TQM, El and TPM to World Cla.ss Manufacturing.

As the technology of production equipment becomes more sophisticated, it is essen-tial that operators and maintenance personnel are provided with the tools and trainingto support the new demands of the equipment. It is also important that productionpersormel take advantage of the new maintenance technologies, such as vibrationanalysis and infrared thermography, that have become useful means for predicting anddiagnosing equipment problems.

The trends in manufacturing techniques and processes make it important for or-ganizations to maintain manufacturing equipment in working condition to meet thehigher performance criteria, produce maximtim returns, and compete aggressivelyworldwide. Thus, TPM has emerged as a result of heightened corporate focus onmaking better use of available resources.

KEY FEATURES OF TPM

Figure 2 provides a framework for considering TPM activities. The elements of theframework have been developed based upon popular TPM literature (Hartmann, 1992;

190 VIII. Lean manufacturing

LcaniLng Organi/alionEducation ant) training

TeamworkEmployee ownership and involvranent

Inventory ReductionLead'time reduciionProduction leveEing

Autonomation

Reduce variationPolicy managementFocus on next process as

customerStatistical ToolsSmall group efTorts

Elimination of eqtiiptnent failuresand quality probiems

Fostering equipment-knowiedgeableworkers

Create disciplined woitplacc

Figur« 1. The mterdependcnce of JIT, TQM, TPM and £L

Nakajima, 1988; Shimbun, 1995; Suzuki, 1992; and Tsuchiya, 1992; Gotoh, 1991),and a number of site visits and interviews with practicing managers. While mainte-nance activities primarily focus on cost reduction and equipment effectiveness, TPM,which emphasizes a company-wide approach to maintenance, also plays a vital rolein improving other manufacturing performance measures. Therefore, improved cost,quality, delivery, flexibility, and innovativeness are important goals ofa TPM programand are represented in the framework.

TPM Values: Critical to successful TPM implementation are its core operating values.Although these values should be tailored to any given organization, they offer broadguidelines for the management of equipment. The following represent the generalvalues of TPM:

Process and product quality are a key part of every person's performance.Equipment failures and off-quality product can and will be prevented.If it ain't broke, fix it anyway.Equipment performance can be managed.

17. Total productive maintenance (TPM) 191

CostQualityDelivery

FlexibilityInnovativeness

Cross Functional TeamsSkill Develo|»nent

Accountabiliiv

Process and product quality are a key part of every person's performanceEquipmeni failures and oil'-quality product can and wil) be prevented

If it ain't broke, fix it any\vayEquipment performance can be managed

3. TPM Prognun

2, Involvement

[Values

Figure 2. A mode! of TPM.

Employee Iiwoli^ement: Every employee should be involved in the TPM process. Account-ability for equipment performance is important to the success ofthe TPM program.However, employees cannot be accountable for quality and predictable production ifthey cannot impact equipment performance. Employees' skills must be developed tomeet the needs of their expanded roles under TPM.

The core values and skills ofthe organization provide the foundation for TPM im-plementation. Cross-functional teams also encourage employee involvement. Teamshelp to break down the barriers that are inherent in the traditional approach to mainte-nance. Teams also help to identify problems and suggest new approaches for eliminationofthe problems, introduce new skills, initiate training programs, and defme TPM pro-cesses.

The TPM Program: While TPM is commonly associated with autonomous and plannedmaintenance activities, the program also includes other activities that help to improveequipment effectiveness over the entire life of the equipment. These activities in-clude: Training, Early Equipment Design, Early Product Design, Eocused Improve-ment Teams, and Support Group Activities (Tajiri and Gotoh 1992; Nakajima, 1988;Gotoh, 1991). The six major TPM activities are reviewed below.

TPM training should be given to every employee. Although internal capabilities maynot be sufficient to achieve the goals of TPM at the start ofthe program, the capabilitiesfor continuation of TPM must be developed. Also, as needs develop, training should

192 VIH. Lean manufacturing

I

support new TPM activities such as inspection, periodic restoration, and predictionanalysis.

Early equipment management activities are typically driven by the research and develop-ment or engineering fiancdons within the organization. Early equipment managementconsiders the trade-offs between equipment attributes encompassing reliability, main-tainabihty, operability, and safety. The engineering efforts involve the consideration ofthe life-cycle costing for equipment purchases as well as comprehensive commissioningperiods prior to full production.

Early product design involves efforts to simplify the manufacturing requirements andimprove quality assurance through product design. By considering these factors in theproduct-design stage, it is easier to meet the diversified needs of consumers in termsof product features, design, quality, and price. The shop-floor employees can focus onmaintaining the process and equipment rather than on working out the logistics ofmanufacturing the product.

Focused improvement team efforts help to eliminate the major equipment-related lossesincluding breakdown losses, setup and adjustment losses, minor stoppage losses, speedlosses, quality defects and rework losses, and start-up/yield losses. Typically, selecting aprocess-improvement team to resolve a particular problem eliminates the major losses.The team then identifies and analyzes the cause ofthe problem, plans and implementsa solution, checks the results, and if improvement occurs, develops standards to ensurethat the improved conditions will remain. The improvement team also documents itswork so that others can learn 6x)m its improvement efforts.

Support group activities ensure that the production department does not produceuseless or wasteful products, and that orders are fiUed on time, at the quaUty andcosts that the development and engineering departments prescrihe. This is not the soleresponsibility ofthe production department; it requires a TPM program that embracesthe entire company, including the administrative and support departments.

Much ofthe day-to-day maintenance planning and execution is performed by theproduction and maintenance personnel. These efforts are represented by the Au-tonomous and Planned Maintenance activities in Figure 2. Together, production andmaintenance groups help to improve the effectiveness ofthe maintenance program. Asoperators are trained, they begin to inspect and maintain the equipment and performbasic maintenance tasks. This assignment of maintenance tasks to production operatorsfrees up time for maintenance personnel to perform long-term improvement effortsand plan maintenance interventions.

FIVE PHASE IMPLEMENTATION

The autonomous and planned maintenance efforts are typically divided into four phasesthat correspond to the four stages of maintenance development proposed by Nakajima(1988); they are also frequently included in subsequent books (Tajiri and Gotoh, 1992;Nachi-Fujikoski, 1990; Suzuki, 1992). We also include a fifth stage that foresees the fu-ture direction of TPM efforts. This phase incorporates the many TPM activities that arenot direcdy part of autonomous or planned maintenance roles. Figure 3 shows a five-phase Bramework for autonomous and planned maintenance development under TPM

17. Total productive maintenance (TPM) 193

g 1.

•g Ia. s

5 "̂« ¡̂ r£ »a Q £ E

ni c\

& &

¡1

— M f-l

55 M iî

ïnooiooDiny

194 VIII. Lean manuiâcturing

and includes typical steps for implementation. The five phases are described in detailbelow.

A practitioner's framework for autonomous and planned maintenance is shown inFigure 3. It is accepted by practitioners, easy to understand, and closely depicts themanagerial decisions made for maintenance on a day-to-day basis within the plant.

(1) Phases I and II—Equipment Improvement: The first phase of TPM involves effortsto reduce the variability in equipment life span. This phase involves the removal ofassignable causes that reduce equipment life span. The efforts include restoration andcleaning of the equipment. At this stage, practitioners must decide how much timeand money to invest in restoring the equipment to a base condition.

The main objective of Phase II is to lengthen the equipment's life. In this stage, thecleaning and lubrication procedures become standardized and operators are educated toconduct detailed inspection of all equipment. Companies must decide how much timeand money to invest in training operators and technicians. Cross-training personnelcan make an organization more flexible and more responsive to maintenance needs;however, some tasks will still be too difficult or unsafe for operators to perform. AnotherPhase II decision is to make investments in eliminating the root causes of contaminationand failure, and to simplify the inspection and maintenance tasks. Finally, practitionersmust decide how much time to invest in order to sustain the equipment at its basecondition.

Both Phase I and II assume that it is possible to change the distribution of equipmentfailure occurrences. This assumption is central to the TPM philosophy. In traditionalmaintenance, the assumption is made that equipment conditions deteriorate over dme,leading to failure or the need for replacement. With TPM, investments are made toreduce equipment problems; the assumption is that a goal of zero failures and defectsis achievable.

(2) Phase ¡II: After implementing the fint two phases, equipment conditions shouldbe dependable and operating conditions should be consistent. Equipment life span canbe accurately estimated, and mechanics and operators can plan periodic inspectionsand renovations. Phase III of TPM development begins to determine the best typeand interval of inspections and repairs.

It is interesting that much of the traditional maintenance literature supports thedecisions involved in Phase III of TPM development. Essentially, the failure rate isassumed to be a ñinction of the equipment, and little attention is given to the possibilityof improving the equipment or restoring the equipment to a better condition {Phase 1and II decisions).

See McCall (1965), Pierskalla and Voelker (1976), and Valdez-Flores and Feldman(1989) fora comprehensive reviews of literature relevant to this phase of maintenancemanagement.

Most of the Phase III literature compares the cost benefits of various mainte-nance poUcies: preparedness or preventive maintenance, and periodic- or sequential-replacement policies. More recent work extends the base models to incorporatemulti-component equipment and multi-state equipment conditions, or relax someof the assumptions of earlier models.

17. Total productive maintenance (TPM) 195

Phase III models have been extremely effective in the development ofa philosophyof preventive versus reactive maintenance. Most organizations realize that it can bebeneficial to replace equipment prior to failure, when die costs of breakdowns arehigh. However, in practice, the replacement interval is often chosen based on theequipment manufacturers recommendations. Therefore, intervals are often establishedwithout considering the actual failure distribution (based on the environment in whichit operates) or maintenance costs (based on the downtime costs associated with aparticular plant). Research is needed to develop better estimates ofthe actual failuredistribution and the associated maintenance costs.

(3) Phase IV: Phase III allows operators and technicians to gain a deeper understand-ing ofthe equipment and process. Phase TV permits personnel to use this new knowl-edge about equipment deterioration, together with diagnostic techniques, to predictfailures of equipment, and eliminate equipment-related quality problems. Condition-based maintenance helps get additional time out ofthe equipment as well as eliminateunexpected failures. The practitioner must thus decide where, when, and how to useprediction tools. In addition, maintenance policies must be coordinated with quality-control policies in order to reduce product quality problems.

Traditionally, equipment maintenance was treated as a method for increasing equip-ment availability'. The goal of maintenance was to keep the equipment running. Withthe advent of quality-management efforts, however, the condition ofthe equipmentbecame important to control the quality ofthe product. Several recent papers addressthe relationship between maintenance and quality; some examples are presented here.Tapiero (1986) considers the problem of continuous-quality production and machinemaintenance. In his model, quality is assumed to be a known function of the machine-degradation state. He considers open-loop (based on quantity or age of equipment)and closed-loop (based on the equipment condition) stochastic control-maintenanceproblems. Rahim (1994) presents a model for jointly determining the economic pro-duction quantity, inspection schedule, and control-chart parameters for an imperfectproduction process.

Predictive maintenance is commonly discussed in trade journaLs; however, very littleacademic research focuses on this area. McKone and Weiss (1999) consider the joint useof continuously monitoring prediction tools as well as periodic maintenance policiesin order to minimize maintenance costs. They recommend that periodic tools not beabandoned for the use of predictive tools, and provide decision rtües for selecting theappropriate periodic policy, when predictive tools are available.

The product quality literature clearly provides some support for this stage of TPMdevelopment. Tools and techniques that help to define, identify, and eliminate knownand/or potential failures, problems, and errors in the system are important to equip-ment improvement efforts. For example. Failure Model and Effect Analysis (FMEA)(Stamatis, 1995) helps to identify plant equipment and process problems that resultin product quality problems. FMEA can help to link both maintenance and qualityimprovement efforts.

(4) Phase V: The fifth phase involves an organization-wide focus on plant produc-tivity. First, design teams made up of engineers, maintenance personnel, and operators

196 VIII. Lean manufacturing

prepare equipment cleaning and inspection standard.s, and personnel are trained to pro-duce efficiently and effectively. Phase V decisions also consider non-maintenance sys-tems, such as spare parts, raw materials, and production scheduling, that impact theequipment productivity and quality. Finally, efforts are made to eliminate losses inlabor, energy, and materials in addition to equipment efficiency The decisions in thisphase primarily focus on organizational and systemic issues.

Phase V is comprehensive. At this phase, flinctional areas within manufacturingmust be carefully integrated. Essentially, all six TPM activities must be coordinated foreffective and efficient equipment operation.

Other issues in implementation

Thilander (1992) conducted a case study of two Swedish firms in an effort to definethe benefits ofthe organizational aspects of TPM. The study shows that well-definedareas of responsibility, one individual who holds the overall responsibility for the main-tenance, and direct contact between the operators and maintenance technicians havepositive impact on productivity.

There are several case studies of TPM that present the TPM development story orexamples of TPM improvement activities in plants (Varughese, 1993; Shimbun, 1995;Steinbacher and Steinbacher, 1993, Chapter 15; Hartmann, 1992; Tsuchiya, 1992;Suzuki, 1992, Chapter 4; and Tajiri and Gotoh, 1992). These studies also include stepsfor TPM implementation.

Key Concepts: Autonomous and Planned Maintenance; Employee Involvement; Just-in-time manufacturing; Preventive Maintenance; Productive Maintenance; ReactiveMaintenance.

Related Articles: Just-in-Time Manufacturing; Lean Manufacturing Implementation;Predictive Maintenance; The Case of Delia Steam Plant; Total Quality Management.

REFERENCES

Anderson, M.Q. (1981). "Monotone Optimal Preventative Maintenance Polices For StochasticaUy FailingEquipment." Naiial Research Logistics Quarterly, 28, 347—358.

Bain, L. J. and M, Engelhardt (1991). Statistical Analysis Of Reliability And Life-Testing Models. Marcel Dekker,Inc., New York.

Chikte, S.D. and S.D. Deshmukh (1981). "Preventive Maintenance And Replacement Under AdditiveDamage." Narnl Research Logistics Quarterly, 28, 33-46.

Dada, M. and R. Marcellus (1994). "Process Concrol With Learning." Operations Reseanh, 42 (2), 323-336.Fine, C.H. (1988). "A Quality Control Model With Learning EfFects." Operations Research, 36 (3). 437-444.Gotoh, F. (199!). Equipment Planning For Tpm: Maintenance Prevention Design, Productivity Press, Cambridge,

MA.Hartmann, E.H. (1992). Successfully Installing Tpm hi A Non-Japanese Plant. Tpm Press, Inc., Allison Park,

PA.Jorgenson, D.W. and J.J. Mccall (1963). "Optimal Scheduling Of Replacement And Inspection.'" Operations

Research, 11, 723-747.Lee, H.L. and M.J. Rosenblatt (1989). "A Production And Maintenance Pbrming Model With Restoration

Cost Dependent On Detection Delay." IIE Transactions, 21 (4), 368-375.Marcellus, R.L. and M. Dada (1991). "Interactive Process Quality Improvement." Management Science, 37

(11), 1365-1376.

17. Total productive maintenance (TPM) 197

Mccall, J.J. (1965). "Maintenance Policies For Stochastically Failing Equipment; A Survey." ManagementScience. 11 (5), 493-524.

McKone, K., R. Schroeder, and K. Cua (1999). "TotaJ Productive Maintenance: A Contextual View."Journal Qf Operations Management, 17 (2). 123—144,

McKone, K., K. Schroeder, and K. Cua (1998a). "The Impact Of Total Productive Maintenance PracticesOn Maniifacturing Perforen a nee." Carbon School Working Paper.

McKone, K. and E. Weiss (1997a). "An Autonomous Maintenance Approach To Cycle Time Reduc-tion: Guidelines For Improvement." Darden School Working Paper Series, Dswp-97-30, University OfVirginia, Charlottes ville, VA.

McKone, K. and E. Weiss (1997b). "Analysis Of Investments In Autonomous Maintenance Activities."Carlson School Operations And Management Science Department Working Paper 97—7, University OfMinnesota, MinneapoUs, MN,

McKone, K. and E. Weiss (1999). "Managerial Guidelines For The Use Of Predicbve Maintenance." DardenSchool Working Paper Series, University Of Virginia, Charlottesviíle, VA.

N.ichi-Fujikoshi Corporation (1990). Training For TPM: A Manufacturing Success Story. Productivity Press,Cambridge, MA.

Nakajima, S, (1988), Introduction To TPM. Productivity Press, Cambridge, MA.t)zekici, S. and S.R. Pliska (1991). "Optimal Scheduling Of Inspections: A Delayed Markov Model With

False Positive And Negatives." Operations Research, 39 (2), 261—273.l'até-Cornell, M.E.. H.L. Lee, and G. Tagaras (1987). "Warning Of Malfunction: The Decision To Inspect

And Maintain Production Processes On Schedule Or On Demand." Management Science, 33 (10), 1277-129(1,

I'lL'rskalla, W.P andJ.A. Voelker (1976). "A Survey OfMaintenancc Models: The Control And SurveillanceOf Deteriorating Systems," Nai^l Research Logistics Quarterly. 23, 353-388,

Kahim, M.A. (1994). "Joint Deterinination Of Production Quantity, Inspection Schedule, And ControlChart Design." HE Transactions, 26 (6), 2-11.

Schonberger, R.J. (1986). \-Vorld Class Manufacturing: The Lessons Of Simplicity Applied, Free Press, N.Y.Shimbun, N.K. (Ed.) (199.S). Tpm Case Studies, Producbvity Press, Portland, Oregon.Steinbacher. H,R. and N,L, Steinbacher (1993). TPM For America: What ¡1 Is And IVIiy VOH Need It.

Productivity Press, Cambridge, MA,Stamatis, D.H. (1995). Failure Mode And Effect Analysü. ASQC Quality Press, Milwaukee, Wl.Suzuki. T. (1992). Neuf Directions For Tpnt, Productivity Press, Cambridge, MA.Tajiri, M. and F Gotoh (1992). TPM Implementation: A Japanese Approach, Mcííraw-Hill, Inc., New York.Tapieru. CIS. (1986), "Continuous Quality Production And Machine Maintenance." Naval Research Logistics

Quarterly. 33, 489-499,I Inlander, M. (1992). "Some Observations Of Operation And Maintenance In Two Swedish Firms."

Integrated Manufacturing Systems, 3 (2),Thompson, G, (1968). "Optimal Maintenance Policy And Sale Date Of A Machine." Management Science,

14 (9), 543-550.Tsuchiya, S, (1992). Quality Maintenance: Zero Defects Through Equipment Management, Productivity Press,

Cambridge, MA,Valdez-Flores, C. and R,M. Feldman (1989). "A Survey Of Preventative Maintenance Models For Stochas-

tically Deteriorating Single-Unit Systems," Naval Reseanh Legistia Quarterly. 36, 419—446.Varughese, K.K, (1993), "Total Productive Maintenance." University Of Calgary, A Thesis For The Degree

Ot Master Of Mechanical Engineering,Waldinan, K,H. (1983). "Optimal Replacement Under Additive Damage In Randomly Varying Environ-

ments." Naval Research Logistics Quarterly. 30, 377-386.