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International Journal of IT, Engineering and Applied Sciences Research (IJIEASR) ISSN: 2319-4413 Volume 1, No. 1, October 2012

i-Xplore International Research Journal Consortium www.irjcjournals.org

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OEE Improvement by TPM Implementation: A Case Study Amit Kumar Gupta1, Dr. R. K. Garg2

1Associate Professor-Deptt. of Mechanical Engineering, CEC, Landran, Mohali (India) 2Professor- Deptt. of Industrial and Production Engineering, NIT Jalandhar (India)

ABSTRACT

The manufacturing industry has gone through significant changes in the last decade. Competition has increased dramatically. Customers focus on product quality, product delivery time and cost of product. Because of these, the organization should introduce a maintenance system to improve and increase both quality and productivity continuously. Total Productive Maintenance (TPM) is a methodology that aims to increase the availability of existing equipment hence reducing the need for further capital investment. The aim of this paper is to study the effectiveness and implementation of TPM programme in an automobile manufacturing organization. Through the case study of implementing TPM in an automobile manufacturing organization, the increase in efficiency and productivity of machines in terms of Overall Equipment Effectiveness (OEE) are discussed. On the basis of results a database has been prepared which can be further used.

The paper is organized as: Section 1 gives introduction about maintenance function. Section 2 discusses literature review regarding development of TPM. Section 3 gives details about the steps in implementation of TPM. Section 4 describes detailed TPM implementation in the case company. The improvements in OEE after TPM implementation are described in Section 5. Section 6 discuses the results and conclusions of the work. Section 7 describes the scope of study.

1. INTRODUCTION

Maintenance has become more challenging in the current dynamic business environment. It is considered one of the important strategic decisions in operations management (Heizer and Render, 2009; Krawjeski and Ritzman, 2002; Russell and Taylor, 2009). The manufacturing sector has been experiencing tremendous challenges in ensuring all products are delivered to customers on time. However, the current business environment and pressures from various parties such as customers, suppliers, governments and so forth have put manufacturing sectors under severe pressure. To

operate efficiently and effectively, manufacturing sectors need to ensure no disruption due to equipment breakdown, stoppages and failure.

Manufacturing systems in particular often operate at less than full capacity, with low productivity, and the cost of producing products are high. Recent study (Mobley,1990) shows that 25-30% of total production cost is attributed to maintenance activities in the factory. The quality of maintenance significantly affects business profitability. The importance of maintenance functions has increased due to its role in keeping and improving the availability, product quantity, safety requirements, as maintenance costs constitute an important part of the operating budget of manufacturing firms (Al-Najjar and Alsyouf 2003:85-100). In response to maintenance problems encountered in manufacturing environment, the Japanese developed and introduced the concept of Total Productive Maintenance (TPM), in 1971. TPM is a maintenance system defined by Nakajima (Nakajima 1988) in Japan, which covers the entire life of equipment in every division including planning, manufacturing, and maintenance. It describes a synergistic relationship among all organizational functions, but particularly between production and maintenance, for continuous improvement of product quality, operational efficiency, capacity assurance and safety.

TPM is an aggressive strategy focuses on actually improving the function and design of the production equipment (Swanson 2001:237-244). TPM aims to increase the availability/effectiveness of existing equipment in a given situation, through the effort of minimizing input (improving and maintaining equipment at optimal level to reduce its life cycle cost) and the investment in human resources, which results in better hardware utilization. Another goal of TPM as stated by Schippers (Schippers 2001:93-105) is to reduce and to control the variation in a process.

2. Literature Survey



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The literature has revealed that the manufacturing organizations worldwide are facing many challenges to achieve successful operation in today’s competitive environment. Modern manufacturing requires that to be successful, organizations must be supported by both effective and efficient maintenance practices and procedures. Modern equipment management began with preventive maintenance and evolved into productive maintenance. These approaches both abbreviated as ‘‘PM’’ originated in the US with activities focused in the maintenance department. TPM, however, stands for total productive maintenance with total participation. Till 1950s organizations were carrying out breakdown maintenance. As and when machinery went out of order, maintenance crew was called to attend and put it back to normalcy for production.

Over the past two decades, manufacturing organizations have used different approaches to improve maintenance effectiveness (Roup 1999:32-5). One approach to improving the performance of maintenance activities is to implement and develop a TPM strategy. The TPM implementation methodology provides organizations with a guide to fundamentally transform their shop floor by integrating culture, process, and technology (Moore 1997:88-90).

The concept of TPM originated in Japan’s manufacturing industries, initially with the aim of eliminating production loses due to limitations in the JIT process for production operations. Seiichi Nakajima, vice chairman of the Japanese Institute of Plant Engineers (JIPE), promoted TPM through Japan and has become known as father of TPM. Modern equipment management began with preventive maintenance (PM) and evolved into productive maintenance. First developed in Japan, TPM is team based productive maintenance and involves every level and function in the organization, from top executives to the production floor operators. Japan adopted PM concept in 1951. PM can be thought of as a kind of physical check up and preventive medicine for equipment (Willmott 1994).

Various researchers have noted the importance of TPM implementation in the manufacturing environment (Ahmed et al. 2005:19-42; Ahuja and Khamba 2007:338-52) and in the service sector (Patra et al. 2005:415-24; Pramod et al. 2006:150-71). TPM is considered to be Japan’s answer to US style productive

maintenance (Wal and Lynn 2002:359-66). TPM has been widely recognized as a strategic weapon for improving manufacturing performance by enhancing the effectiveness of production facilities (Dwyer 1999:15-16; Dossenbach 2006:29-32). TPM has been accepted as the most promising strategy for improving maintenance performance in order to succeed in a highly demanding market arena (Nakajima 1988). TPM is the proven manufacturing strategy that has been successfully employed globally for the last three decades, for achieving the organizational objectives of achieving core competence in the competitive environment (Ahuja et al. 2004:422-6).

3. About TPM

TPM is a program that “addresses equipment maintenance through a comprehensive productive-maintenance delivery system covering the entire life of the equipment and involving all employees from production and maintenance departments to top management” (McKone et al. 1999:123-144).

Seiichi Nakajima (Nakajima 1988) has defined TPM as an “innovative approach to maintenance that optimizes equipment effectiveness, eliminates breakdowns, and promotes autonomous maintenance by operators through day-to-day activities involving the total workforce”.

TPM is not a specific maintenance policy; it is a culture, a philosophy and a new attitude towards maintenance. TPM is a major departure from the “I operate, you maintain” philosophy. TPM is a manufacturing-led initiative that emphasizes the importance of: (i) people with a ‘can do’ and continual improvement attitude and (ii) production and maintenance personnel working together in unison. TPM includes participation by all sectors of the organization that plan, use, and maintain equipment.

Total Productive Maintenance (TPM) is a proven and successful procedure for introducing maintenance considerations into organizational activities. It involves operational and maintenance staffs working together as a team to reduce wastage, minimize downtime and improve end product quality. TPM is an aggressive strategy focuses on actually improving the function and design of the production equipment.

In essence, TPM seeks to integrate the organization to recognize, liberate and utilize its own



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potential and skills. The aim of TPM is to bring together management, supervisors and trade union members to take remedial actions as and when required. Total Productive Maintenance (TPM) is a productive maintenance program, which focuses on the following:

• Maximizing overall equipment effectiveness. • Establishing a planned system of Preventive

Maintenance (PM) for the equipment’s life span. • Involving all employees from top management to

shop floor workers. • Empowering employees to initiate corrective

activities. • According to the Nakajima (Nakajima 1988), the

word ‘total’ in TPM has three meanings: • Total effectiveness indicates TPM’s pursuit of

economic efficiency and profitability. • Total maintenance system includes Maintenance

Prevention (MP) and Maintainability Improvement (MI), as well as PM. Basically; this refers to ‘‘maintenance-free’’ design through the incorporation of reliability, maintainability, and supportability characteristics into the equipment design

• Total participation of all employees includes Autonomous Maintenance (AM) by operators through small group activities. Essentially, maintenance is accomplished through a ‘team’ effort, with the operator being held responsible for the ultimate care of his/her equipment.

3.1 Pillars of TPM

The pillars or steps (Yeomans and Millington 1997:170-173) on which the TPM implementation methodology is based are shown in Figure 1.

i) 5S Program: TPM starts with 5S. 5S is the foundation stone of TPM. It is a systematic process of housekeeping to achieve a serene environment in the work place involving the employees with a commitment to sincerely implement and practice housekeeping (Productivity 1998:4-6). 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.

ii) PILLAR 1 - Autonomous Maintenance or Jishu Hozen: This is the basic premise of TPM. “Autonomous maintenance is the process by which equipment operators accept and share responsibility (with maintenance) for the performance and health of their equipment” (Robinson and Ginder 1995). The

attitude of the operator that ‘I just operate it’ is to be changed. TPM encourages the operator to maintain the machine himself. The role of the operator is not only its operation but also to ensure highest productivity of the machine by being actively involved in the maintenance. iii) PILLAR 2 – 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 (Suzuki 1994). Kaizen in Japanese context simply means change (kai) for the better (zen). Kaizen is implemented by lower management and workers but relies heavily on support from senior management. This pillar focuses on that “A very large number of small improvements are more effective in an organizational environment than a few improvements of large value.”

iv) PILLAR 3 – Planned Maintenance: The objective of Planned Maintenance is to “establish and maintain optimal equipment and process conditions” (Suzuki 1994). A system developed to cover daily, weekly and monthly checks in conjunction with identifying symptoms of deterioration and implementing an equipment refurbishment program.

v) PILLAR 4 – Overall Equipment Effectiveness (OEE) Calculation: Measurement is an important requirement of continuous improvement processes. It is necessary to establish appropriate metrics for measurement purposes. From a generic perspective, TPM can be defined in terms of overall equipment effectiveness (OEE), which in turn can be considered a combination of the operation maintenance, equipment management, and available resources. The goal of TPM is to maximize equipment effectiveness, and the OEE is used as a measure (Waeyenbergh and Pintelon 2002:299-313). According to Nakajima (Nakajima 1988), OEE measurement is an effective way of analyzing the efficiency of a single machine or an integrated manufacturing system. It is a function of availability, performance rate, and quality rate. Actually, the three dimensions are measures of the equipment losses. In practice, OEE is calculated as the product of its three contributing factors (Leflar 1999): OEE = Availability X Performance X Quality

For example if all the three contributing factors are 90.0%, the OEE would be72.9 %.

The method of calculating OEE is:



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A

OEE CALCULATION SHEET

Shift Time (General) ___

B Planned Downtime ___

C Running Time (A-B) ___

D Running Time Losses ___

E Operating Time (C-D) ___

F Availability ___ (E/C) x 100

G Output ___

H Machine Speed (No. of components/min)

___

I Expected Output (HxE) ___

J Efficiency ___ (Gx100)/I

K Rejection ___

L Quality ___ (G-K x 100)/G

OEE = Availability x Efficiency x Quality

___

In practice, the generally accepted worldwide goals for each factor are quire different from each other, as shown below:

World Class OEE OEE Factor World Class

Availability 90.0 %

Performance 95.0 %

Quality 99.9 %

OEE 85.0 %

Worldwide studies indicate that the average OEE rate in manufacturing plants is 60%. World class OEE is considered to be 85% or better (Leflar 1999). Clearly, there is a room for improvement of OEE in many manufacturing plants! vi) PILLAR 5 – Education and Training: Education and Training (Nakajima 1984) is the important pillar of

TPM. Training of operators is needed to give them the knowledge of what daily maintenance is needed as well as what are the optimal operating conditions as well. Training of maintenance crew gives them the knowledge of how to monitor, improve and correct design flaws and get equipment restoration. The ultimate goal being that operator’s responsibilities would cover maintenance responsibility.

4. TPM Implementation in Automobile Manufacturing Organization

In this section, the TPM implementation is demonstrated through a case study in an automobile manufacturing organization. Section 4.1 gives a brief review of case organization and then the TPM implementation procedure is discussed in section 4.2.

4.1 About XYZ

XYZ is one of the prestigious automobile manufacturing organizations in India. With the dual objective of industrial and agriculture growth, XYZ was established in 1970. XYZ, is India’s first large-scale project based company with a totally indigenous design, know-how and technology. XYZ is a leading manufacturing organization manufacturing tractors, harvesting combines, fork lifters etc. Till 1998, the organization did not give much attention to the maintenance work. The machines were being checked and repaired only after the breakdown. But with the industrialization, it became necessary to adopt new concepts to survive in the market. The organization decided to adopt “Total Productive Maintenance (TPM)” for its survival.

4.2 TPM Implementation at XYZ

This section discusses implementation of TPM at XYZ organization. Various pillars of TPM i.e. 5S, Jishu Hozen, Kobetsu Kaizen, Planned Maintenance and OEE have been implemented. A maintenance plan has also been prepared. (i) Selection of Machine The first step of this work is selection of machines on which the study is carried out. To start with TPM, a few machines have been selected for implementation of TPM, which is known as TPM model machine. In XYZ, there are seven shops. Four machines have been selected from Light Machine Shop (LMS) i.e. 2 Broaching machines, 1 Cylindrical Grinder and 1 Surface Grinder for TPM implementation. This section was named as TPM model section in Light Machine



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Shop. These machines are used in production of components like bull gear, shafts for power transmission etc. A code is assigned to each machine for ease of identification. Each machine is studied thoroughly to identify each part and to understand the working of every component. Table 1 shows the machines selected for the work, their condition and make. Layout plan of machines in LMS is shown in Figure 2. (ii) Implementation of 5S on these Machines

5S are defined as Sort, Set in Order, Shine, Standardize and Sustain. Because each of the five pillars begins with S, this method was appropriately named 5S. These 5S are implemented on TPM model section.

5S – Sort: The first pillar of 5S helps to clearly distinguish the items needed in a work area from those no longer needed. At XYZ, various items have been sorted out on the basis of priority of use. Low priority denotes the less frequency of use while high priority shows the items used daily/frequently.

5S - Set In Order: The second pillar of 5S helps to keep the needed items in the correct place to allow for easy and immediate retrieval. The correct place, position, or holder for every tool, item, or material must be chosen carefully in relation to how the work will be performed and who will use them easy identification. At XYZ, for organizing activity, the components were stored according to their code number so assigned that the high priority items are located very near to the operator.

5S – Shine: The third pillar of 5S helps to keep work areas, all work surfaces and equipment clean and free from dirt, debris, oil, etc. At XYZ, all the persons from managers to operators were engaged for cleaning their table, chair and cabin.

5S – Standardize: The fourth pillar of 5S defines the standard activities, procedures, schedules and the persons responsible for keeping the workplace in a clean and organized manner. At XYZ color-coding and standardized coloration of surroundings were used for easier visual identification of anomalies in the surroundings

5S – Sustain: SUSTAIN is the last pillar of 5S and drives the organization to be disciplined in maintaining

these new standards and procedures and in continuously improving the 5S state of the workplace.

(iii) Implementation of JISHU HOZEN

Jishu Hozen also called autonomous maintenance is a team-based approach to maintenance activities. The goal of autonomous maintenance is to prepare operators to do some equipment care independently of the maintenance staff. Jishu Hozen implementation lays the foundation for other maintenance activities by establishing the basic conditions for a machine's operation. Various tentative standards for cleaning, inspection and lubrication are set for all machines.

These standards are shown in Table 2, 3 and 4.

Similarly tentative standards of cleaning, inspection and lubrication are set for different machines.

iv) Classification of Fuguaies After setting up of standards for all machines, fuguaies are found in all machines. Fuguaies are the abnormalities in the machine, which is noted during the initial cleanup. Table 5 below shows the various fuguaies found in Broaching Machine-I.

Similarly fuguaies for other machines are found. v) Implementation of Kobetsu Kaizen Around hundred Kaizens are performed on all the machines situated in the LMS. A proper kaizen sheet is filled for each kaizen, which contains all information like before and after photographs, ideas and benefits. So, if any further other modification is suggested then this sheet is very helpful for that. Some of the Kaizens performed on various machines are shown in Table 6:

Kaizen sheets are prepared for Kaizens performed on all machines. Kaizen sheets for Broaching machine –I are shown in Table 7

Similarly Kaizen sheets are prepared for other machines.

vi) Education and Training

Education and Training is the important pillar of TPM. The major problems faced during TPM implementation at XYZ are:



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• Workers are not well educated. • Fear of loosing jobs after adopting TPM. • Extra work to be done in TPM process.

To overcome these problems TPM education and training program has been prepared which is oriented towards three goals:

• Managers will learn to plan for higher equipment effectiveness and implement improvements aimed at achieving zero breakdowns and zero defects.

• Maintenance staff will study the basic principles and techniques of maintenance and develop specialized skills concerning the company’s equipment.

• Equipment operators will learn how to recognize equipment abnormalities as such during their daily and periodic inspection activities.

Education and training programs were conducted for managers, maintenance personnel and operators.

5. Improvements in OEE

According to Nakajima (Nakajima 1988), OEE measurement is an effective way of analyzing the efficiency of a single machine. It is a function of availability, performance rate, and quality rate. OEE is calculated for all the machines before and after implementation.

OEE for Broaching Machine –I.

Before TPM Implementation A Shift Time (General) 450 B Planned Downtime 60 C Running Time (A-B) 390 D Running Time Losses 78 E Operating Time (C-D) 312 F Availability (E/C) x 100 80% G Output 180 H Machine Speed (No. of

components/min) 0.75

I Expected Output (H x E) 234 J Efficiency (Gx100)/I 76.9% K Rejection 8 L Quality (G-K x 100)/G 95.5%

OEE = Availability x Efficiency x Quality = 80% x 76.9% x 95.5% = 58.7%

After TPM Implementation A Shift Time (General) 450 B Planned Downtime 60 C Running Time (A-B) 390 D Running Time Losses 58 E Operating Time (C-D) 332 F Availability (E/C) x 100 85.1% G Output 207 H Machine Speed (No. of

components/min) 0.75

I Expected Output (H x E) 249 J Efficiency (Gx100)/I 83.1% K Rejection 2 L Quality (G-K x 100)/G 99% OEE = Availability x Efficiency x Quality

= 85.1% x 83.1% x 99% = 70%

Similarly OEE is calculated for rest of the machines at LMS section of XYZ.

6. Results and Conclusions

After successful implementation of TPM, it is found that Overall Equipment Effectiveness is increased (Refer table 8 and figure 3). Today TPM may be the only thing that stands between success and total failure for some companies; it has been proven to be a program that works. The results shown above can be much more improved by continuing with TPM.

7. Scope of the Study Today, with competition in industry at an all time high, TPM may be the only thing that stands between success and total failure for some companies TPM can be adapted to work not only in industrial plants, but also in construction, building maintenance, transportation, and in variety of other situations. Employees must be educated and convinced that TPM is not just another



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“program of the month” and that management is totally committed to the program and the extended time frame is necessary for full implementation. If everyone involved in a TPM program does his or her part, a usually high rate of return compared to resources invested may be expected. TPM success requires strong and active support from management, clear organizational goals and objectives for TPM implementation.

Table 1. Machines selected for TPM Implementation S.No.

Name of Machine

Make

Stock No.

Breakdown Frequency (Shift/mont

h) 1 Broachin

g Machine – I

HMT 354.01

1.2

2 Broaching Machine – II

HMT 352.02

1.0

3 Cylindrical Grinder

HMT 527.01

0.95

4 Surface Grinder

PRAGA

512.03

0.85

Table 2. Standards for Cleaning (Broaching Machine-I)

Table 3. Standards for Inspection (Broaching Machine-I)

Table 4. Standards for Lubrication (Broaching Machine-I)



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Table 5. Fuguaies found in Broaching Machine-I

Table 6. Kaizens performed on Machines



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Table 7. Kaizen Sheet for Broaching Machine -I

Table 8. OEE Improvement before and after TPM Implementation

Name of Machine

OEE (%) Before After

Broaching Machine –I

59 70

Broaching Machine –I

60 69

Cylindrical Grinder

53 67

Surface Grinder 50 65

Fig. 1 Pillars of TPM

Figure 2. Layout of Machines in LMS

Figure 3. OEE Improvement before and after TPM Implementation

References [1] Ahmed, S., Hassan, M.H. and Taha, Z. (2005),

“TPM can go beyond maintenance: excerpt from a case implementation”, Journal of Quality inMaintenance Engineering, Vol. 11 No. 1, pp. 19-42.

59 6053 50

70 69 67 65

0

20

40

60

80

Broaching Machine -IBroaching Machine -IICylindrical GrinderSurface Grinder

OEE

(%)

Improvement in OEEOEE before implementation of TPMOEE after implementation of TPM



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[2] Ahuja, I.P.S. and Khamba, J.S. (2007), ‘‘An evaluation of TPM implementation in an Indian manufacturing enterprise’’, Journal of Quality in Maintenance Engineering, Vol. 13 No. 4, pp. 338-52.

[3] Ahuja, I.P.S., Singh, T.P., Sushil, M. and Wadood, A. (2004), “Total productive maintenance implementation at Tata Steel for achieving core competitiveness”, Productivity, Vol. 45 No. 3, pp. 422-6.

[4] Al-Najjar, B. and Alsyouf, I. (2003). “Selecting the most efficient maintenance approach using fuzzy multiple criteria decision making”, International Journal of Production Economics, 84(1):85-100.

[5] Dossenbach, T. (2006), “Implementing total productive maintenance”, Wood and Wood Products, Vol. 111 No. 2, pp. 29-32.

[6] Dwyer, J. (1999), “More than a maintenance technique”, Works Management, Vol. 52 No. 9, pp. 15-16.

[7] Heizer, J. and Render, B. (2009), “Operations Management Flexible Edition”, 9th ed., Pearson Prentice-Hall, Upper Saddle River, NJ.

[8] Krawjeski, L.J. and Ritzman, L.P. (2002), “Operations Management: Strategy and Analysis”, 6th ed.,Prentice-Hall, Upper Saddle River, NJ.

[9] Leflar, J. (1999). TPM at Hewlett-Packard. 10th Total Productive Maintenance Conference, Las Vegas, NV, Productivity, Inc.

[10] McKone, K. E., R. G. Schroeder, et al. (1999), “Total Productive Maintenance: A contextual View.” Journal of Operations Management 17: 123-144.

[11] Mobley RK (1990). An introduction to predictive maintenance. Plant Engineering Series, Van Nostrand Reinhold, New York, 0-442- 31828-6.

[12] Moore, R. (1997), “Combining TPM and reliability-focused maintenance”, Plant Engineering, Vol. 51 No. 6, pp. 88-90.

[13] Nakajima, S. (1984). Introduction to TPM: Total Productive Maintenance. Cambridge, MA, Productivity Press.

[14] Nakajima, S. (1988), “Introduction to Total Productive Maintenance”, Cambridge, MA, Productivity Press.

[15] Patra, N.K., Tripathy, J.K. and Choudhary, B.K. (2005), ‘‘Implementing the office total productive maintenance (‘office TPM’) program: a library case study’’, Library Review, Vol. 54 No. 7, pp. 415-24.

[16] Pramod, V.R., Devadasan, S.R., Muthu, S., Jagathyraj, V.P. and Moorthy, G.D. (2006), ‘‘Integrating TPM and QFD for improving quality in maintenance engineering’’, Journal of Quality in Maintenance Engineering, Vol. 12 No. 2, pp. 150-71.

[17] Productivity, Inc. (1998), “Phillips 66 and Vistreon Emphasize Recognition Over Rewards.” TPM Report 8(10): 4-6.

[18] Robinson, C. J. and A. P. Ginder (1995). Implementing TPM: The North American Experience. Portland, OR, Productivity Press.

[19] Roup, J. (1999), “Moving beyond TPM to total plant reliability: redefining the concept to optimize benefits”, Plant Engineering, Vol. 53 No. 2, pp. 5-32.

[20] Russell, R.S. and Taylor, B.W. (2009), “Operations Management: Creating Value along the Supply Chain”, 6th ed., Wiley, New York, NY.

[21] Schippers, W.A.J., 2001, “An integrated approach to process control”, International Journal of Production Economics 69 (1), 93–105.

[22] Suzuki, T., Ed. (1994). TPM in Process Industries. Portland, OR, Productivity Press.

[23] Swanson, L., 2001, “Linking maintenance strategies to performance”, International Journal of Production Economics 70(3), 237–244.

[24] Waeyenbergh, G., Pintelon, L., 2002, “A framework for maintenance concept Development”, International Journal of Poduction Economics 77 (3), 299–313.

[25] Wal, R.W.E. and Lynn, D. (2002), “Total productive maintenance in a South African pulp and paper company: a case study”, The TQM Magazine, Vol. 14 No. 6, pp. 359-66.

[26] Willmott, P. (1994), “ Total Productive Maintenance: The Western Way”, Oxford, England, Butterworth- Heinemann, LTD.

[27] Yeomans, M. and P. Millington (1997), “Getting Maintenance into TPM”, Manufacturing Engineer: 170- 173.

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