Final Paper Instructions/Guidelines: The final paper must be a minimum of 5 pages and a maximum of 7 pages in APA format. You can find APA guidelines in the Week Six folder under final paper tips. The paper will constitute of a literature review. You must select at least 3 articles (that have been provided) and analyze how the presented theories in the articles can improve maintenance programs in your workplace. The paper is not a summary of the articles however, you may include a brief summary. You will need to include an abstract, introduction and conclusion. Please make sure to adhere to the APA guidelines.

Optimizing Maintenance Management Efforts by the Application of TOC: A Case Study Mahesh Pophaley* and R K Vyas** The Industrial Age has given way to the Information Age. This transition calls for unmatched kind of organizations filled with innovations, since success in the past does neither assure continued success nor a good reputation or bigger size in future. It is not uncommon for large businesses to have millions of dollars invested in production assets. Today, the management of maintenance function, of these assets, which range from factory machines to huge power generating units are increasingly being viewed as strategic contributors to company's profit and loss. The constant increase in capital needed for this function has recently directed vast interest in two methodologies: Total Productive Maintenance (TPM) and Theory of Constraints (TOC), that are found to be adequate to optimize returns on capital invested. This paper presents a case study of initiating TPM implementation backed by TOC application in an automobile company. As the case with many continuous improvement projects in maintenance management, TPM program is often launched using Pareto analysis by focusing on the resource with the most unscheduled downtime. The logic behind this approach is that such a resource presents the biggest potential for improvement. While the logic appears obvious the question remains: Is this always true? The specific purpose of this paper is to demonstrate a new and innovative approach for directing maintenance improvement initiative using the theory of constraint principle. Further, this research also shows that both the methodologies are convergent and the ideas and concepts of the two different approaches to improvement can be combined to give the company a unique competitive advantage. Introduction In today's global economy the survival of companies depends on their ability to rapidly innovate and improve. As a result, an unceasing search is on for methods and processes that drive improvements in quantity, costs, and productivity. Thus, in this fast-changing * Reader, Department of Mechanical Engineering, Medi-Caps Institute of Technology and Management, Indore, Madhya Pradesh, India; and is the corresponding author. E-mail: mahesh_pophaley@rediffmail.com ** Reader, International Institute of Professional Studies, Devi Ahilya Vishwavidyalaya (DAVV), Indore, Madhya Pradesh, India. E-mail: ramkrishnavyas@gmail.com . 48 2010 IUP All Rights Reserved. The IUP Journal of Operations Management, Vol. IX, No. 3, 2010 marketplace, slow and steady improvements in manufacturing operations will not guarantee profitability or survival. Companies must improve at a faster rate than their competitors if they are to become or remain leaders. To confront this challenge, enlightened company leaders are adopting and adapting 'best-in-class' manufacturing practices and improvement processes. As part of these benchmarking efforts, Total Productive Maintenance (TPM) and Theory of Constraints (TOC) have been identified as improvement philosophies. Since traditional approach to maintenance function has not been able to provide any dramatic improvement in performance, TPM as an upcoming industrial maintenance program, seems to provide the answer. Further, TPM is a new and fast growing concept among industries, assessing inefficiencies and determining where to focus improvement actions, i.e., identifying the problem areas to implement TPM, is the most interesting task for the plant managers. Included in the Continuous Flow Manufacturing (CFM) strategy is an improvement process, called theory of constraints, which outlines a methodology to achieve continuous flow manufacturing. The philosophy concentrates on maximizing throughput while simultaneously reducing operating expenses. CFM can be defined as a manufacturing philosophy which strives to continually reduce manufacturing inefficiencies through improvements in logistics. This can be complementary to TPM's focus on equipment-related losses. Although TOC and TPM have entirely different roots, the processes support one another. When both are effectively coordinated in implementation, they provide an unbeatable team. The case presented in this paper refers to the work carried out at an automobile component manufacturing unit located in Central India. Within the ABC automobile unit, company management emphasizes effective maintenance management to reduce cost of maintenance and increase availability of equipments and throughput of the system, that are their improvement goals. To achieve these goals, the company has started implementing TPM in their production shops for efficient maintenance of production units to minimize the downtime. A case study was undertaken in the company to direct the TPM efforts for effective maintenance along with maximizing pipeline throughput, considering effective bottleneck-constraint management to help realize dual goals. The fundamental principle used was that the output of the production pipeline is limited by and can never be greater than the output of the 'primary constraint'. It was anticipated that the combined methodology will support in setting the priorities for addressing the critical maintenance issues along with increasing throughput. The rest of the paper is organized as follows: It provides a literature survey, followed by brief description of the theory of constrains. Subsequently, it covers the details of case study research, followed by the analysis of shop floor data. Finally, the findings of the paper are summarized as conclusion. An Appendix is given at the end of paper containing various tables showing results in support of analysis. Optimizing Maintenance Management Efforts by the Application of TOC: A Case Study 49 Literature Review The literature describes numerous applications of TPM and TOC principles in both manufacturing and non-manufacturing environments. Chaudhari and Mukhopadhyay (2003), in their research illustrate an application of TOC thinking processes in a service industry, namely the integrated poultry industry where interactions among the supply chain members were analyzed. In addition, the paper also demonstrates how a generic evaporating cloud was developed from three clouds each related to a specific undesirable effecta recent advance in TOC thinking processes. It highlights the fact that TP tools are particularly useful to address nonphysical constraints such as wrong policies or inconsistent performance measures. Kayton et al. (1997), in their study indicate clearly the serious detrimental effects of downtime on non-constraint machinery, particularly in environments with re-entrant product flows such as semiconductor wafer fabrication. The study resulted in, managements significantly revising their views of the causes of their problems, and prompted a significant effort to improve the maintenance function and reduce downtime. In the past few decades, a number of attempts have been made to redesign and analyze manufacturing systems. But most of them were not intended to facilitate productivity measurement and analysis. The turning point in the history of productivity measurement and analysis came when the concept of Overall Equipment Effectiveness (OEE), an integral part of the TPM paradigm was proposed by Nakajima (1997). TPM is an innovative approach to maintenance, that optimizes equipment effectiveness, eliminates breakdowns, and promotes autonomous operator maintenance through day-to-day activities involving the total workforce. Robinson and Ginder (1995), in their book stated that term 'total productive maintenance' was first used in the late 1960s by Nippondenso, a supplier of electrical parts to Toyota. At that time it was a slogan for their plant improvement theme, \"productive maintenance with total employee participation\". In 1971, Nippondenso received the Distinguished Plant Award from the Japan Institute of Plant Maintenance (JIPM). Nippondenso was the first plant to receive the award as a result of implementing TPM, and this marked the beginning of JIPM's association with the improvement methodology. Eventually Seiichi Nakajima, Vice-Chairman of JIPM, became known as the 'Father of TPM', since he provided implementation support to hundreds of plants, mostly in Japan. They explained the concept of TOC philosophy, and explored that the terms 'bottleneck' and 'Capacity Constrained Resource (CCR)' are not synonymous. A bottleneck resource is defined as one whose available capacity is equal to or less than the capacity required by the demand placed on it. A CCR is defined as \"any resource which, if not properly scheduled and managed, is likely to cause the actual flow of product through the plant to deviate from the planned product flow\". Scoggin et al. (2003), in their paper illustrate an application of the TOC thinking processes in a manufacturing environment. The paper demonstrates how a team of 50 The IUP Journal of Operations Management, Vol. IX, No. 3, 2010 employees used TP tools to document current reality, identify a core conflict and develop proposed changes to address the core problem, and create several detailed action plans to implement the changes. It provides insights into how to apply TOC processes to analyze a company's manufacturing strategy Umble et al. (2006), in their case study on Hitachi Tool Engineering highlight two important issues. One is that the TOC philosophy works very well in a traditional Japanese environment, in both manufacturing and non-manufacturing functional areas. Another issue highlighted is that the literature describes numerous applications of TOC principles and a vast majority of these reported applications have occurred in the US and most of the remainder have occurred in countries dominated by western culture and business practices. The website, TOC-Goldratt.com identifies companies that have undergone TOC-based implementations and are willing to publicly share their results. This site currently contains 95 references, 63 of which involve the US firms. The remaining 32 firms are from the UK(8), Ireland(3), Germany(1), Canada(2), Mexico(2), South Africa(5), Israel(3), Venezuela(1), Uruguay(1), Estonia(1), Lithuania(1), Czech Republic(1), Colombia(1), and India(2). With few exceptions, the literature is clearly lacking in case studies of TOC applications in Asian organizations, and as far as the authors can ascertain, contains no case studies of TOC applications in Indian automobile industry. Theory of Constraints The theory of continuous flow manufacturing was developed by Eliyahu M Goldratt and was first described in an educational novel, The Goal. This book describes the philosophy and its accompanying methodology (TOC) by using the story of a fictitious plant manager as he struggles to make his plant profitable. TOC is an approach to business which focuses on achieving the goal of that business, i.e., to make more money now and in the future. Goldratt stated that a business, like any system, operates with constraints. A constraint is defined as anything that limits the performance of a business relative to its goal. Another important aspect of TOC is its unique approach to improvement that does not focus on cost reduction, but instead focuses on increasing throughput. Under TOC, throughput is defined as the money generated by the system through sales. It is the throughput value (selling price minus raw material cost) which represents the value added to the product by the system. TOC strives to continuously increase the money generated by the system. The foundation of TOC is a five-step process for improving a system by focusing on the constraints of that system. These steps are (Umble et al., 2006): 1. Identify the primary constraints of the system. 2. Decide how to exploit the constraints. Optimizing Maintenance Management Efforts by the Application of TOC: A Case Study 51 3. Subordinate all other actions to exploit the constraints. 4. Determine if it is necessary to elevate the constraints. 5. If a constraint is broken in the previous step, return to the first step and repeat the process. It was believed that TOC can play an important role in successful implementation of TPM to reduce downtime and cost of maintenance, and increase throughput. With the bottleneck and near bottleneck equipment identified, the TPM teams identify and stratify the losses associated with these pieces of equipment. The teams that work on near bottleneck equipment, that feeds the bottleneck, work to reduce Mean Time to Repair (MTTR), since extended periods of downtime will starve the bottleneck equipment. The teams working on the bottleneck equipment focus on improving OEE and increasing Mean Time Between Failures (MTBF). This results in appropriate increases in productive capacity, i.e., increase in the overall rate of throughput and reduction of starvation and blockage at the bottleneck equipment. If a resource is not a CCR, then, by definition it has more capacity than demand. Consequently, it is possible that even though that resource has the most downtime, it also has sufficient capacity to absorb that downtime, without affecting the system's ability to achieve its scheduled target. Conversely, if a resource is a CCR, by definition, any amount of unscheduled downtime will adversely affect the systems ability to meet its schedule. From a TPM program's point of view, it illustrates that for a resource with relatively little downtime, the improvement potential for the system would be biggest if its impact on the systems ability to meet its schedule and produce throughput is high. As stated earlier, the TOC approach concentrates on increasing throughput rather than reducing costs, therefore it would evaluate directing a TPM program in the same manner, leaving TPM to work on the cost front. Case Study Overview of the Automobile Company ABC automobile company uses state-of-the-art technology to produce and manufacture automobile products. The plant described in this study is a classic plant and exhibits all the standard problems of a traditionally managed company, existing within the unique framework of Indian work culture. The plant management has been keen in applying the continuous improvement activities in maintenance function and has already implemented practices like 5S, Kaizen, and Daily Management, to improve productivity, lower manufacturing costs and achieve excellence. One major initiative being taken at ABC is TPM. Methodology A comparison of the traditional and newly-conceived integrated methodology for effective maintenance management is given in Figure 1. The system's constraint must 52 The IUP Journal of Operations Management, Vol. IX, No. 3, 2010 be identified early in the TPM implementation process by using TOC principles. Once the constraint is identified, Small Group Activity Teams (SGATs) are formed to apply TPM methodologies for improving performance. Figure 1: Approaches of Effective Maintenance Management Traditional Approach of Applying Improvement Processes in Maintenance Function 1. Identify the resources with the unscheduled downtime An Integrated Approach in Applying Improvement Process 1. Analyze the resources by TOC methodology and identify CCR and non-CCR 2. Apply the improvement process on the resource which is a CCR 2. Arrange the resources in the decreasing order of downtime (Pareto Analysis) 3. Start the improvement process with the resource having highest unscheduled downtime 3. Exploit the constraint to utilize its capacity, which generates the most monetary return 4. Repeat the steps 1 to 3 to identify new CCR for improvement process, till all resources become non-CCR General Information 1. Plant operates one shift of 8 hours per day, 6 days per week (i.e., 2,880 minutes per week; excluding 30 minutes for lunch per day and overtime is not allowed). 2. There is one worker per station. 3. Selling price of product X = Rs. 6,000 per unit, and selling price of product Y = Rs. 7,000 per unit (rounded off accurately to the nearest zero). 4. Average market demand for product X and product Y = 60 units per week (demand is stable and continuous). 5. Average rate of production for both the products is assumed as 10 units per day. 6. Downtimes for each station have been collected and are presented in Table 1 (based on previous year history/data sheet of each station). Optimizing Maintenance Management Efforts by the Application of TOC: A Case Study 53 7. The actual layout of the final machining and assembling shop where this case study was carried out is presented in Figure 2, along with the quantity of Raw Materials (RM) required per day. 8. Simplified flow diagram of material with scheduled processing/assembling time per unit at each station is presented in Figure 3, along with the cost of raw materials per unit. It also shows individual product routing information. Here product alternatives are not allowed. Table 1: Average Downtime at Each Station Per Day S. No. Station No. Downtime (Avg.) Downtime (Approx. %) 1. Station A 1 h 35 min/day 20 2. Station B 2 h/day 25 3. Station C 2 h 25 min/day 30 4. Station D 2 h 50 min/day 35 Figure 2: Layout of Final Machining and Assembling Shop Station C P RM2 (20 units/day) Station A P P RM3 (10 units/day) P Station B Station D Y (10 units/day) X (10 units/day) P RM1 (10 units/day) P P A P: Processing; A: Assembling Observations and Analysis To utilize the TOC approach for directing maintenance management efforts, the manufacturing system of ABC was examined very critically and final machining and assembly section was chosen to apply the concept of TOC before implementing TPM. This section makes two types of products X and Y, and uses four work stations equipped with various machines. Figure 4 demonstrates and simplifies the product-wise calculations of processing/assembling time required at each station, per week. 54 The IUP Journal of Operations Management, Vol. IX, No. 3, 2010 Figure 3: Simplified Flow Diagram of Shop with Processing/Assembling Time at Each Station D B 12 min/unit (P) RM1 Rs. 800/unit 21 min/unit (P) D 4 min/unit (A) Product X A RM2 Rs. 1,000/unit 28 min/unit (P) C 8 min/unit (P) A 20 min/unit (P) D RM3 Rs. 600/unit C B 12 min/unit (P) 8 min/unit (A) Product Y 21 min/unit (P) Figure 4: Individual Manufacturing Flow Diagram for Product X and Y X Y A A 28 min/unit = 1,680 min 20 min/unit = 1,200 min B B 21 min/unit = 1,260 min 21 min/unit = 1,260 min RM1 RM2 C C RM2 8 min/unit = 480 min 8 min/unit 12 min/unit = 480 min = 720 min 1,200 min RM1 D 12 min/unit 4 min/unit D X = 720 min = 240 min Y 8 min/unit = 480 min 960 min Optimizing Maintenance Management Efforts by the Application of TOC: A Case Study 55 Launching TOC Initiative In order to determine the priority of TPM implementation for stations A, B, C and D, the steps of TOC were applied to these stations and the constraint was identified. This was accomplished by computing the capacity requirements at each station to satisfy the market demand (see in Appendix, Table A1). Available capacity and load profiles were calculated on the basis of downtime given in Table 1. The figures in Table 1 show that both stations A and B have insufficient capacities to satisfy demand. Consequently they are both bottlenecks in the system. However, it is Station A that requires the highest utilization at 125%, which makes it the primary constraint limiting the performance of the system. Therefore, stations A and B are CCR, while stations C and D are non-CCRs. Since Station A is the current CCR limiting the system's performance, TPM efforts should first be focused on Station A. Once the primary constraint has been identified, the next step in the TOC continuous improvement process is to exploit the constraint. One way of exploiting a constraint as per TOC theory, is to utilize its capacity of processing products, which generates most monetary returns on the basis of time spent on that resource. This factor is referred to as the Throughput Value per Constraint Time Utilization (TV/CTU) as stated by previous researchers. Table A2 shows that product X has a TV/CTU of Rs. 150 per minute and product Y has a TV/CTU of Rs. 270 per minute, therefore product Y makes more profitable use of the CCR than product X. Therefore, the most profitable mix has to be determined to take maximum advantage of this situation. Since product Y is more profitable, it should be processed first. After making 60 units of Y, with the remaining available capacity only 39 units of product X can be processed. This is the most profitable product mix for this situation. Because the market demand for X and Y are 60 units each, the customer service potential for this condition is 82.5% and the throughput money generating capability is Rs. 4,87,800 per week. By eliminating the downtime at Station A, the available capacity of this resource becomes 2,880 minutes per week, which enables it to fully utilize its capacity. Eliminating the downtime on Station A has the impact of elevating the constraint (Step 4), and so it leads us to (Step 5), which directs us to go back and re-identify the new system constraint, if any. In order to determine the constraint (Step 1), we once again compute the capacity requirements to satisfy the market demand (see Table A3). The table reveals that after eliminating downtime on Station A, Station B becomes the new system CCR (with required utilization of 116.6%). Unfortunately, the system is still unable to fully satisfy market demand because resource B is now the new CCR. Subsequently, evaluation was done to analyze the impact of this decision on customer service level and throughput potential of the system. To exploit the new constraint (Step 2), the TV/CTU for it was determined. Table A4 shows that product X yields a TV/CTU of Rs. 200 per minute and product Y generates a TV/CTU of Rs. 257.1 per minute. Since product Y is more profitable, it should be produced first. After making 56 The IUP Journal of Operations Management, Vol. IX, No. 3, 2010 60 units of Y, the remaining capacity enables the system to produce 42 units of X. Therefore, eliminating the downtime at resource A allows the shop to process three additional units per week. This increases the customer service level to 85% and the throughput capability of the system by Rs. 12,600 to Rs. 5,00,400 per week. Efforts are now focused on resource B, since it becomes the new system CCR. Eliminating downtime at Station B increases its available capacity to 2,880 minutes per week. Since a CCR has been broken, it is suggested to repeat the process. In order to determine where the system constraint is now, the capacity requirements are again computed. Table A5 reveals that no station becomes the CCR, rather Station A has the load profile of 100%. Once again, the impact of this decision on the customer service level potential and throughput capability of the system is evaluated. However, system capacity is now sufficient to meet market demand so the new optimal product mix is 60X and 60Y. By focusing TPM efforts at resource B, 18 additional units of X were produced, leading to an increase in customer service level to 100% and the throughput generating capability to Rs. 5,76,000 per week. Since resources C and D are non-CCRs, by focusing TPM efforts on these resources, no additional units could be processed through the system. Consequently, no matter how much effort is placed on TPM projects of these resources, the customer service and throughput potential of the system would remain unchanged. Of course, the downtime of the non-CCRs needs to be investigated in due course, but if non-CCRs are not obstructing the system's ability to meet its targets, urgent actions may not be necessary. Directing TPM Program by Traditional Approach Based on Pareto analysis, MII would have been focused on resource D first, since it has the highest downtime (35%), followed by C (30%), B (25%) and A (20%). However, eliminating downtime at resources D, C and B (by applying MII) does not allow the system to process more units (i.e., the optimal product mix remains at 39X and 60Y). This is because resource A remains the CCR for the system (see Table A6). Therefore, the customer service potential for this system remains at 82.5% and the throughput potential also remains at Rs. 4,87,800 per week. But this results in increased maintenance cost and extra burden on maintenance team without reaping any benefits in return. Continuing with the improvement program, we would implement TPM on Station A. Eliminating downtime at Station A by MII, can increase its available capacity to 2,880 minutes per week. Since the available capacity of resources B, C and D is already 2,880 minutes per week (see Table A7), sufficient capacity would now be available to meet the market demand, so that the product mix will be 60X and 60Y. Thus, customer service potential becomes 100 % and the throughput capability increases to Rs. 5,76,000 Optimizing Maintenance Management Efforts by the Application of TOC: A Case Study 57 per week. This scenario illustrates how using the Pareto approach to set the priority of TPM improvement projects can be unreliable. Under this approach all four resources would need to undergo the maintenance improvement process, before the system experiences any tangible monetary benefits. The final sequence is presented in Figure 5. Figure 5: Final Sequence of Applying MII at Various Stations By Traditional Pareto Analysis D C By New Integrated TOC Analysis A B B A C or D Conclusion This case study makes a theoretical contribution by defining a conceptual framework to implement a new maintenance function improvement initiative, which shifts focus from a traditionally-driven approach to a new TOC-based approach. It is demonstrated that to be successful in a new maintenance initiative like TPM, the TOC methodology should be adopted, otherwise the gains obtained by a typical TPM program could be lost in the form of idle time. It is widely accepted that bottlenecks should enter a TPM program, but for the non-bottlenecks, it is not easy to determine which machines should enter the program, their target and their impact on the overall efficiency. The conceptual framework suggested in this research, allows a company to tackle maintenance problem in a more controlled manner. Although maintenance might still remain a source of expense, the procedure depicted in this case study will permit to reduce costs and save time, thereby increasing profitability, while maintaining or even improving customer satisfaction. This is done by enabling optimum use of machine capabilities and through improved maintenance planning. Further early in the implementation of TPM, ABC has already seen positive benefits in many domains of the company. Linking TOC to improvement initiatives, such as TPM, becomes key in ABC's relentless pursuit to improvement. One major aim is to allow TOC to be the common culture shared by all entities in the company. The ABC case study presented in this paper highlights two important lessons. The first lesson is that the TOC philosophy could work well if properly thought and implemented in a traditional Indian manufacturing environment. And the second important lesson is the typically insidious and pervasive nature of a core problem. That is, a core problem is likely to cause dysfunctional behaviors throughout the organization. Thus, when a core problem is discovered, it must be resolved before proceeding further with changing initiatives. Acknowledgment: The authors gratefully acknowledge the support of all who participated in this case study, particularly the maintenance manager and his team, for their useful suggestions, consultation in understanding the complexities of production system, data tracking and patient listening and recognizing the theoretical concepts. 58 The IUP Journal of Operations Management, Vol. IX, No. 3, 2010 References 1. Chaudhari C V and Mukhopadhyay S K (2003), \"Application of Theory of Constraints in an Integrated Poultry Industry\Total Quality Management Vol. 20, No. 5, May 2009, 497 -507 Costs of quality and maintenance: Improvement approaches Larry Weinsteina , Robert J. Vokurkab and Gregory A. Gramanc a Department of Information Systems and Operations Management, Wright State University, Dayton, OH 45435, USA; bDepartment of Finance, Economics, and Decision Sciences, Texas A&M University - Corpus Christi, Corpus Christi, TX 78412, USA; cMichigan Technological University, Houghton, MI 49931, USA The inclusion of maintenance-related costs in an organisation's nancial reports, through the analysis of the costs of maintenance, helps management evaluate the relative impact of its maintenance problems on the organisation's protability. A cost of quality (COQ)/cost of maintenance (COM) system, once implemented, provides us with an invaluable foundation for our efforts to improve the effectiveness of the maintenance function. This approach provides us with a common language for communication between top management and the maintenance function to draw attention to where management should provide resources to correct quality problems and make improvements. The system provides new channels for communication to share best practices and to coordinate the efforts of experts in quality management with those in maintenance to improve our understanding of the statistical capability and reliability of equipment. Keywords: maintenance; cost of quality (COQ); total productive maintenance (TPM) Introduction Since the 1980s, organisations have faced rising operating costs and intense competition both domestically and overseas. Firms have discovered that they cannot compete successfully in the global marketplace without paying close attention to the quality of their products and services. Foreign competitors, most notably from Asian rms, use quality as a strategic weapon to gain market share from US industry. It is important therefore that American rms better understand the consequences of poor quality in all aspects of their business in order to more effectively compete. Not only will their customers no longer tolerate inferior quality in their products and services, but rms can no longer afford the nancial losses attributable to poor quality. This paper investigates how to integrate the concepts of cost of quality (COQ) and cost of maintenance (COM) to create a more effective approach to establishing an appropriate maintenance policy for an organisation. It also explores how such integration can help organisations analyse the impact that each of these costs has on the other. This analysis should help organisations reduce overall costs. Total quality management and cost of quality During the 1980s, quality-related activities within the typical manufacturing rm evolved from a narrow production-based technical discipline into an organisation-wide performance system that permeated every aspect of the business. Organisations began to integrate quality principles into their management systems through a total quality management Corresponding author. Email: larry.weinstein@wright.edu ISSN 1478-3363 print/ISSN 1478-3371 online # 2009 Taylor & Francis DOI: 10.1080/14783360902863648 http://www.informaworld.com 498 L. Weinstein et al. (TQM) approach. This evolution derived from A.V. Feigenbaum's comprehensive approach to quality (Feigenbaum, 1956). Feigenbaum coined the phrase 'total quality control', which he dened as 'an effective system for integrating the quality development, quality maintenance, and quality improvement efforts of the various groups in an organisation so as to enable production and service at the most economical levels which allow full customer satisfaction' (Feigenbaum, 1991, p. 6). Two of the earliest references to the COQ concept can be found in Juran's Quality control handbook (1951) and Feigenbaum's article 'Total quality control' (1956). Organisations that use the COQ approach strive to increase protability by reducing the operating costs incurred from poor-quality processes and products (Feigenbaum, 1956; Juran, 1951). Quality costs represent the difference between the actual cost of a product or service and what the reduced cost would be if there were no possibility of substandard service, product failure or defects in their manufacture (Campanella, 1999). The American Society for Quality (ASQ) Quality Costs Committee, established in 1961 to dramatise the importance of product quality through measurements of the costs of quality, published Quality costs: What and how to describe the components of a quality cost programme (ASQ, 1967). The COQ concept was further popularised in Philip Crosby's book Quality is free (Crosby, 1979). Crosby (1979, p. 18) states that 'the only performance measurement is the cost of quality, which is made up of the expense of non-conformance.' Crosby nds that many organisations spend 15 - 20% of their sales dollars on quality costs; whereas a company with a well-run quality management programme can achieve a COQ that is lower than 2.5% of sales. Crosby's programme calls for measuring and publicising the cost of poor quality and for using the results of these efforts to drive improvements (Crosby, 1979). Masser (1957) divides quality costs into the categories of prevention, appraisal and failure. He denes prevention costs as those costs incurred to keep nonconforming products and services from occurring, and thereafter reaching, the customer. They include quality planning costs, costs for new product review, training costs, process control to achieve tness for use, quality data acquisition and analysis, quality reporting, and the costs associated with carrying out quality improvement projects (Evans & Lindsay, 2005; Juran & Gryna, 1988). Appraisal costs are those costs associated with efforts to ensure compliance with requirements, generally by measuring and analysing data to detect non-conformance. These costs include test and inspection of incoming materials, the work in process, and all nished goods, as well as salaries and equipment costs; instrument maintenance costs due to calibration and repair of measuring instruments; and process measurement and control costs, which involve the time workers spend gathering and analysing quality measurements (Evans & Lindsay, 2005). Failure costs occur when products or services do not conform to requirements or customer/user needs. Failure costs can be either internal or external. Internal failure costs occur before the product is shipped or delivered, or before a service is provided, to the customer. Examples are the costs of scrap, rework, re-inspection, retesting, material review and downgrading. External failure costs occur after the product is shipped or delivered, or while or after a service is provided, to the customer. Examples include the costs for processing customer complaints, customer returns, warranty claims and product recalls (Campanella, 1999). Quality experts estimate that 60- 90% of total quality costs are the result of internal and external failure costs. These costs are management's responsibility. In the past, managers reacted to high failure costs by increasing inspection. However, such actions only increase appraisal costs. The overall result is little, if any, improvement in quality or productivity. The Total Quality Management 499 preferred approach is to increase prevention costs in order to generate larger savings in all other cost categories. Often, there is an order of magnitude difference between each of the quality costs. For example, the cost of replacing a low-quality component in the eld (i.e. external failure) might be $500; the cost of replacement after assembly (i.e. internal failure) might be $50; the cost of testing and replacement (i.e. inspection) during assembly might be $5; and the cost of changing the design to avoid the problem (i.e. prevention) might be only 50 cents (Evans & Lindsay, 2005). The primary value of a COQ approach is that it enables organisations to identify opportunities for improvement and to measure that improvement over time. Since the volume of business varies over time, real differences in quality costs can best be measured over the long term as a percentage of some appropriate base, such as net sales, or a percentage of net sales. Short-term comparisons should relate the COQ to such key measures of production as overall operating costs, total or direct labour costs, or the average cost of a delivered product or service (Campanella, 1999). The COQ is a nancial measurement that expresses vital information in the language of management. While workers and supervisors typically speak in the language of 'things' (e.g. units and defects), top management focuses on the processes and procedures that have a nancial impact on the business. Financial consequences get management's attention, and they demonstrate where managers should provide resources to correct quality problems and make improvements. A COQ report enables an organisation to determine how all departments impact on the cost of quality. It helps managers pinpoint areas of high quality costs, increases efforts to improve, and facilitates an organised approach to productivity and cost improvements. Maintenance function and costs Maintenance is dened as 'the activities intended to preserve or promptly restore the safety, performance, reliability, and availability of plant structures, systems and components to ensure superior performance of their intended function when required' (Weinstein, 1996, p. 1061). Personnel who perform maintenance in a production environment strive to make capacity available to production in a reliable and stable manner. Their efforts help to ensure responsive customer service, consistent product quality, reliable product output, cost-efcient operations and high equipment utilisation (Ettkin & Jahnig, 1986). Maintenance costs include preventive, inspection-based and unscheduled or emergency maintenance activities. An optimal maintenance policy minimises the sum total costs for maintenance activities, as well as the nancial consequences caused by interruptions to the production schedule (Weinstein, 1996). Several authors address the issue of establishing maintenance policy using techniques such as simulation analysis, linear programming and multiple goal programming (e.g. Rishel, 1991; Weinstein, 1996). Preventive maintenance is a proactive approach that requires an organisation to schedule regular maintenance work in order to reduce repair and lower maintenance costs. Interruptions to the production schedule may include normal wear of production equipment, failures resulting from unperformed inspections and services, and unanticipated stresses to the equipment. Planned service allows an organisation to prevent breakdown by detecting weak points and replacing parts that may be usable but do not meet reliability standards (Clair, 1986; Ettkin & Jahnig, 1986; Priel, 1974). A comprehensive preventive maintenance programme provides many benets. It minimises maintenance costs; gives management the opportunity to plan production 500 L. Weinstein et al. interruptions; improves the availability of materials, equipment and personnel; enables the organisation to subcontract maintenance activities; reduces downtime; minimises the spare parts inventory; reduces the number of disruptions caused by emergency maintenance; improves documentation for future reference; lessens the need for standby equipment; reduces the amount of overtime; and enhances the organisation's ability to apply safety rules (Mann, 1976). Inspection-based maintenance is a proactive approach that requires an organisation to observe equipment to determine whether it is operating properly. Such an inspection enables managers to decide whether preventive or corrective maintenance is needed. Using an inspection list or a handheld computer, the inspectors document visible malfunctions, as well as malfunctions they suspect may occur based on how the equipment looks, sounds, feels or smells. Although some inspections must be performed when the equipment is shut down, most can be completed while equipment is operating. This avoids a shutdown and allows the organisation to maintain its production schedule. For example, a pump cannot really be inspected when it is down since there are no vibrations, operating pressures or sealed water ow (Idhammar, n.d.). Common quality practice discourages the use of inspection as a quality system; however, inspection-based maintenance could be considered a form of preventive maintenance. Preventive and inspection-based maintenance activities may be production-/run-based or calendar-/interval-based. Run-based maintenance is scheduled according to the equipment's level of usage. As production demands increase, the resources required for maintenance will also increase. Calendar-based maintenance is performed at specied intervals of time, regardless of production volume. Changing a car's oil every 3000 miles is a runbased preventive maintenance activity. Changing the oil every three months is a calendarbased preventive maintenance activity. Emergency maintenance activities are performed when production equipment exhibits signs of failure, or after failure has occurred. Sole reliance on emergency maintenance is a reactive approach that may adversely affect both the integrity of the production plan and the quality of the product (Ettkin & Jahnig, 1986; Weinstein, 1996). An organisation that holds large quantities of work-in-process (WIP) inventory may nd that an emergency maintenance policy is adequate. Such an organisation can be compared to an organisation that accepts high rates of product failure because the organisation lacks a comprehensive quality programme and because the scrap from its failed product is inexpensive. On the other hand, an organisation with a just-in-time or lean manufacturing programme may benet from a policy that emphasises scheduled preventive and inspection maintenance activities that reduce emergency maintenance. Maintenance policy An organisation's maintenance policy prescribes how the organisation allocates resources for scheduled and unscheduled maintenance activities. In general, when an organisation allocates more resources for scheduled or preventive maintenance, it can allocate fewer resources for unscheduled or emergency maintenance. Management's challenge is to determine the optimum level of scheduled maintenance activities: too few, and the organisation faces unscheduled interruptions to the production schedule; too many, and the organisation may not have the amount of equipment it needs for production (Weinstein, 1996). In order to achieve an optimal maintenance policy, an organisation must make decisions that resolve conicting objectives of system reliability and prot Total Quality Management 501 maximisation/cost minimisation (Hardy & Krajewski, 1976). Top management determines the maintenance policy by allocating resources for the performance of maintenance activities. In contrast, an organisation that lacks a formal process for determining its maintenance policy may experience a situation in which production managers and maintenance personnel vie for machine availability. In striving to make equipment completely reliable, maintenance personnel attempt to impose constraints on production's access to equipment. This, in turn, angers the production managers. In such cases, where critical strategic decisions are made at the operational level through a political test of wills and authority, the organisation may end up with a less-than-optimal maintenance policy. This, in turn, keeps the organisation from meeting its overall objectives. In order to achieve an optimal maintenance policy that meets the organisation's production goals, top management must create a planning model that successfully integrates maintenance and production planning activities (Weinstein, 1996). Organisations taking a total productive maintenance (TPM) approach consider maintenance planning to be part of the overall business strategy. In these organisations, maintenance planning is coordinated with manufacturing activities (Nakajima, 1988; Rhyne, 1990). With TPM, maintenance activities are part of the production process rather than an interruption of that process. The production schedule is interrupted only by an unscheduled maintenance activity needed to prevent equipment failure or undertaken as a result of a failure. Before an organisation can successfully implement a proactive approach, maintenance personnel must be able to impose binding constraints on the production schedule. Violations of the service standards are seen as violations of the production plan integrity. These violations have the potential to destabilise the production environment and to upset the nal assembly schedule. In a TPM environment, equipment failure is synonymous with product failure. The extent to which the maintenance policy affects the production environment varies by organisation. In some, interruptions to the production schedule have an insignicant effect. In others, production's need for stability is critical. When equipment fails, an organisation is subject to several consequences. For example, the equipment may be severely damaged and require considerable expenditures for repair or for replacement parts. Equipment failure may also result in lost production time. As a result, the organisation may need to pay its staff overtime in order to satisfy production requirements. Equipment failure may also lead to poor product quality. Failed equipment may continue to produce parts that do not meet quality standards. As a result, the parts must be inspected, evaluated, and then reworked or scrapped. A high-failure cost environment suggests an organisation that may have to pay a premium penalty for emergency maintenance activities or that risks considerable nancial consequences if its production schedule is interrupted. This organisation values production stability. A low-failure cost environment implies an organisation that incurs insignicant costs when the production plan is disrupted. This organisation values proactive maintenance. Parallels of maintenance to quality The management concepts of just-in-time and lean manufacturing focus on the elimination of waste and non-value-added activities in all processes. Maintenance is essential to the successful implementation of these concepts. TPM helps to ensure that equipment is operational and available when needed (Evans & Lindsay, 2005). Miyake and Enkawa (1999) show how total quality control (TQC) and TPM can complement each other in reducing the COQ. TQC's product and services improvement measures emphasise quality. 502 L. Weinstein et al. TPM's improvement measures emphasise equipment maintenance, an increase in production effectiveness, and the improvement of engineering and manufacturing capabilities. TQC and TQM share similar objectives: TQC strives for zero defects; TQM strives for zero breakdowns. TQC assesses the non-conformance of products based on the prevention of defects, reworks, claims and product liability. TPM assesses non-conformance based on abrupt breakdowns, malfunctions, repairs and accidents. Many authors have documented the benets of problem-solving tools and TPM (Al-Najjar, 1996; Blanchard, 1997; Cassady et al., 2000; Horner et al., 1997; Imai, 1986; Juran & Gryna, 1988; Nakajima, 1988; Riis et al., 1997). These authors show that it is more effective to 'work smarter' by eliminating any process problems that degrade process quality. In short, improving equipment reliability through TPM ultimately improves process quality (Jambekar, 2000). The pressures of production, coupled with the need to be efcient and make on-time deliveries, often render it difcult for an organisation to take a proactive approach to maintenance activities. Jambekar cites comments such as 'a little bit of preventive maintenance would have avoided such a costly breakdown', 'we do not have any resources to do preventive maintenance in response to these vibration tests' and 'we wish our maintenance people could get their act together, so we do not have so many breakdowns . . . we are their customers' (Jambekar, 2000, p. 127). An organisation can take a proactive approach to its manufacturing- and service-related activities, or it can simply react to problems. Similarly the organisation can take a proactive or reactive approach to maintenance activities. In either case, there are trade-offs. The remainder of this article discusses two approaches to using COQ to improve operational productivity. The rst shows how maintenance and quality costs are linked. The second addresses how COQ can be applied to maintenance costs. Linkage between maintenance and quality costs The linkage between maintenance and quality costs can be illustrated with several examples. The rst three of these examples occurred at a Midwestern steel mill that produces at-rolled, low-carbon steel used to supply the automobile and appliance markets. The last more recent example illustrates the enormous indirect consequences of failing to incorporate indirect costs into maintenance policy determination. Case I: The steel mill fabricates steel panels that it subsequently ships to one of its customers for painting or enamelling. The panels are visible to the consumer and must, therefore, be free of defects such as scratches, nicks, contamination and blemishes. Achieving high levels of surface quality in the nal product is largely dependent on the surface quality of the steel and on the customer's coating operations. A high-quality, defect-free steel surface is critical to the material's performance during the coating process. Defects in the steel panels may cause the customer to reject them; if detected prior to shipment, they may cause the mill itself to scrap the panels. The steel mill performs an electroplating operation that deposits metallic zinc on to the steel substrate. On one occasion, the wipers that contact the surface during plating wore beyond an acceptable level. Maintenance workers improperly replaced the wipers with ones made out of a different material. This deviation caused the customer to incur failure costs for problems it experienced from wiper material embedded in the steel surface. The alternative material had reduced the steel mill's preventive maintenance costs; but the costs of identifying the problem, reworking automobile bodies after painting, and regaining the customer's goodwill were enormous. Thus, an improperly performed maintenance Total Quality Management 503 activity - intended to reduce maintenance costs - resulted in an enormously high external failure cost. Case II: The steel mill produces primary shapes of steel in a continuous casting process during which molten metal is cast directly into the desired shape and then extracted from the machine. Uniformity in the product shape is critical for uniform cooling, and it directly affects nal product performance, which can only be measured after several weeks of subsequent operational stages. Production's failure to cast the steel properly can result in distorted shape-forming rolls and in products with unacceptable dimensions. The steel mill's original maintenance procedure specied processes for conrming the alignment of the forming rolls and, if necessary, for replacing them; but because roll replacement was expensive and time consuming, the mill performed it only in cases of extreme misalignment, meaning that the rolls were replaced far less frequently than the original maintenance procedure called for. Ignoring the prescribed maintenance procedures led to dimensional problems that the mill detected only after subsequent operations had been performed. In this case, the mill's effort to reduce preventive maintenance costs resulted in a high product-failure cost. Case III: The steel mill, like others in the steel industry, performs a common forming operation called hot rolling. Scale that forms on the surface of the steel during this process is detrimental to surface quality. The steel mill used high-pressure water sprays to remove the scale. However, unacceptable levels of scale were continually found during subsequent operations, resulting in internal rejection of the product. The mill's existing maintenance procedure of visually inspecting the spray nozzle alignment and condition was inadequate to conrm the effective removal of scale while the equipment was in operation. The mill subsequently developed a procedure to assess the effectiveness of scale removal by subjecting a piece of painted plywood to the spray during scheduled downtime. The plywood was examined for a pattern that indicated effective scale removal and that helped identify faulty spray nozzles. Here, an increase in preventive maintenance resulted in a reduction in internal product-failure costs. Case IV: In March 2006, a leak developed in a British Petroleum (BP) pipeline in Alaska, causing a spillage that equalled nearly 5000 barrels of crude oil (Schwartz, 2006). To clean pipelines, BP performed a preventive and inspection-based maintenance activity that involved sending a device through the pipes that would clean, as well as monitor, the pipes for corrosion, cracks, sediment deposits and other threats that might cause leaks. However, BP performed this maintenance activity much less frequently on this particular pipeline than on other critical lines - once in 8 to 15 years versus, for example, every 14 days for the Trans-Alaska Pipeline. As a result of the spillage, BP incurred emergency maintenance costs for the clean up of the spill. Clean up destroyed a two-acre patch of ground and shut down of much of Prudhoe Bay, causing the loss of hundreds of millions of dollars. Moreover, the spillage wounded BP's decade-long reputation for environmental concern. Interviews with former BP employees revealed an internal company culture that was driven by 'intense pressure to keep costs down', resulting in budgeting decisions that 'often took precedence over routine maintenance'. One individual said that 'no one should be surprised by what eventually occurred. The mantra was, \"Can we cut costs 10%?\"' In these case studies, improperly performed maintenance activities, the failure to perform prescribed maintenance activities, and increased preventive maintenance activities all affected the organisations' COQ. These examples demonstrate why management needs to use COQ to make maintenance policy decisions that will keep costs low. 504 L. Weinstein et al. Applying the COQ concept to maintenance A COQ analysis enables top management to see the bottom-line impact of quality-related costs in the organisation. The analysis draws greater attention to quality problems, helps management determine how to allocate resources to those problems, and drives improvement efforts. A COQ analysis that includes maintenance-related costs demonstrates how those costs impact on an organisation's protability. An analysis of the COM enables management to see how maintenance costs change over time, and it gives management a sound basis for making decisions about shifting the allocation of expenditures from emergency to inspection-based to preventive activities. The inclusion of maintenance-related costs in nancial reports helps management evaluate the relative importance of maintenance problems. Management can more effectively identify major improvement opportunities and then allocate resources accordingly. In many organisations, maintenance is seen as a distinct cost centre. However, accounting rarely categorises its costs by type of maintenance activity. The COM analysis should include distinct categories for preventive, inspection-based and emergency (or unplanned) maintenance. Costs should be expressed both in dollar amounts and as a percentage of activity costs (such as production costs) to allow for comparisons across units and over time. In almost all cases, the COM analysis shows that failure costs for any particular piece of equipment, expressed in units of time, will exceed inspection- and preventionbased costs. Harrington suggests that failure costs also include the following: costs that customers incur when a product or service fails to meet expectations; costs for customer dissatisfaction; and costs for loss of reputation. The degree to which these costs are included depends on the importance the company places on its customer (Harrington, 1987). COM costs should also include the indirect costs associated with equipment failure (scrap, rework, lost production, lost goodwill, expedited shipments, and so on). Only by including these costs can management get an accurate picture of the COM. Any effort to reduce overall costs will have to take these indirect costs into consideration. Implementing a COM system Harrington (1987) recommends a 15-step process for developing a COQ system. This approach may also be used to develop a COM programme or, alternatively, to integrate COM elements into the development of a COQ system. (1) Form an implementation team under the leadership of the company controller. The team should include quality assurance personnel. (2) Present the concept to top management. (3) Develop a multiple-stage implementation plan. The plan should begin with items that currently exist in the nancial data system and then expand to include major and detail items that require changes to the way nancial data are collected and reported. (4) Select a trial area. This should be a self-contained area whose managers are open to new ideas and willing to accept change, and that has an existing cost database and a need to improve quality. (5) Start the programme by presenting it to management in that area. (6) Identify and classify the system cost elements. (7) Determine when each quality cost element will be introduced into the system. (8) Establish inputs into the system. Total Quality Management 505 (9) (10) (11) (12) Design the output formats needed by various levels of management. Establish the additional data system required to support the system. Review the project status with the plant management team. Start the trial period by forming a system-improvement team to review the COQ data. (13) Review the monthly report. (14) Based on ndings, modify the system to meet the needs of other areas in the organisation. (15) Expand the programme throughout the organisation (Harrington, 1987). The implementation team should include a maintenance representative, and the implementation plan should incorporate maintenance activities. The team should factor maintenance activities in to the selection of a trial area, and it must apply the processes used to assess COQ and COM to the trial area as soon as realistically possible. The team should also develop an efcient process for collecting and recording maintenancerelated data. The team's nal report should present information in a format that gives top management a clear picture of how COM impacts on the organisation. The reporting system should be accompanied by an effective improvement process that uses the cost data to direct efforts and measure progress (Harrington, 1987). The report changes the abstract into specic information that enables management to evaluate the magnitude of their maintenance quality problems and to establish priorities for addressing them. In reviewing the report, management should weigh how much the company pays for each of the preventive, inspection and emergency maintenance costs. It should consider where in the manufacturing process the company incurs maintenance costs, and why. The report provides a channel for effective communication between the maintenance function and top management, using the common language of dollars. It demonstrates to top management how reducing the costs described in the report will improve the company's bottom line (Harrington, 1987). Conclusion A COQ/COM system, once implemented, provides us with an invaluable foundation for our efforts to improve the effectiveness of the maintenance function. The system generates information we can utilise to establish credible goals for reducing our quality costs. We can evaluate and improve our organisation's maintenance policy using sound data and analysis. The system gives us a benchmarking process that allows us, over time, to compare our performance across units within our facility, between multiple facilities, and against similar organisations in our industry. We can work with our equipment vendors to improve equipment reliability. We can identify where in our facilities we need to place the greatest efforts to reduce the COM. We can open new channels for communication within our facility, and with other facilities within the organisation, to share information about best practices. We can coordinate the efforts of experts in quality management with those in maintenance to improve our understanding of the statistical capability and reliability of equipment. Top management support is critical to the successful implementation of a maintenance programme. By involvement of management in the practice of maintenance management, the culture of the organisation is sensitised to the importance of supporting an effective maintenance programme (Madu, 2000). Establishing a COM system is only a rst step in building a culture that values quality maintenance practices in the 506 L. Weinstein et al. organisation. As stated earlier, the COQ/COM approach provides us with a common language for communication between top management and the maintenance function to draw attention to where management should provide resources to correct quality problems and make improvements. Any rm wanting to improve its competitiveness and ensure its long-term survival must look inward and, through self-assessment, identify areas of incompetence, malfunction, loss, and misallocation of resources (Miyake & Enkawa, 1999). The approach described in this paper is a key component of this process. References Al-Najjar, B. (1996). Total quality maintenance: An approach for continuous reduction in costs of quality products. Journal of Quality in Maintenance Engineering, 2(3), 4-20. ASQ. (1967). Quality costs: What and how (1st ed.). Milwaukee, WI: American Society for Quality Control. Blanchard, B.S. (1997). An enhanced approach for implementing total productive maintenance in the manufacturing environment. Journal of Quality in Maintenance Engineering, 3(2), 69-80. Campanella, J. (Ed.). (1999). Principles of quality costs (3rd ed.). Milwaukee, WI: ASQ Press. Cassady, C.R., Bowden, R.O., Liew, L., & Pohl, E.A. (2000). Combining preventive maintenance and statistical process control: A preliminary investigation. IIE Transactions, 32(6), 471-478. Clair, F.V. (1986). JIT and maintenance management. Production and Inventory Management Review, 6(2), 36, 40, 44, 65. Crosby, P.B. (1979). Quality is free: The art of marking quality certain. New York: McGraw-Hill. Ettkin, L.P., & Jahnig, D.G. (1986). Adopting MRP II for maintenance resource management can provide a strategic advantage. Industrial Engineering, 18(8), 50-59. Evans, J.R., & Lindsay, W.M. (2005). The management and control of quality (6th ed.). Mason, OH: Thomson South-Western. Feigenbaum, A.V. (1956). Total quality control. Harvard Business Review, 34(6), 93-101. Feigenbaum, A.V. (1991). Total quality control (3rd ed.). New York: McGraw-Hill. Hardy, S.T., & Krajewski, L.J. (1976). A simulation of interactive maintenance decisions. Decision Sciences, 6(1), 92-105. Harrington, H.J. (1987). Poor quality cost. Milwaukee, WI: ASQ Quality Press. Horner, R.M.W., El-Harm, M.A., & Munns, A.K. (1997). Building maintenance strategy: A new management approach. Journal of Quality in Maintenance Engineering, 3(4), 273-280. Idhammer, T. (n.d.). Checking best practices for preventive maintenance. Retrieved January 3, 2007, from http://www.idcon.com Imai, M. (1986). Kaizen. New York: McGraw-Hill. Jambekar, A.B. (2000). A systems thinking perspective of maintenance, operations, and process quality. Journal of Quality in Maintenance Engineering, 6(2), 123-130. Juran, J.M. (1951). Quality control handbook. New York: McGraw-Hill. Juran, J.M., & Gryna, F.M. (1988). Quality control handbook. New York: McGraw-Hill. Madu, C.N. (2000). Competing through maintenance strategies. International Journal of Quality and Reliability Management, 17(9), 937-948. Mann, L. (1976). Maintenance management. Lexington, MA: DC Heath. Ma