Integrative Total Productive Maintenance: Lean Practices

A key aspect of lean manufacturing practices is the implementation of an integrative total productive maintenance (TPM) system. Manufacturers and others implementing lean practices need to understand the importance of employee involvement and support of an integrative TPM approach. The paper summarizes key aspects in the literature associated with team based and union environment that support and impede the implementation of integrated TPM as a part of lean practices. Introduction This paper forms the theoretical and conceptual foundation for the further development of an attitudinal questionnaire used to survey union represented employees in several component plants of a major original equipment manufacturer. The discussion revolves around the key aspects of total productive maintenance (TPM) as one of the critical components to successful lean manufacturing implementation. The historical background, current, and future TPM practices are framed in the context of lean manufacturing. Finally the discussion will focus on how a major OEM has developed and applied their TPM approach as a part of their lean manufacturing practices. Subsequent work has been completed to empirically test relationships and predictive measures but is not included in this discussion. Historical Background of Total Productive Maintenance (TPM) Preventive maintenance was introduced to Japan from America in the 1950s, when Japanese process industries were beginning to get back on their feet after the war. Productive maintenance, developed in the 1960’s, incorporates such disciplines as maintenance prevention design, reliability and maintainability engineering, and economic engineering to enhance the economic efficiency of equipment investment for the entire life of equipment (Suzuki, 1994). The Japanese were the first to realize the importance on improved equipment maintenance on gaining the competitive market edge. TPM links to many other initiatives, which include zero defects, lean manufacturing, total quality management (TQM), continuous process improvement, and productivity, to name a few. Another key manufacturing initiative is the just-in-time (JIT) system. To enable a company to properly operate in a JIT environment, maintenance is a critical factor to meet customer requirements. The total integrated supply chain requires that all companies be able to meet each other's requirements. JIT forces companies to go to TPM so as to develop this environment of process predictability. TPM, a term originally coined by General Electric in the early 1950’s sadly has been largely neglected in the U.S. until recently. The philosophy behind TPM parallels that of total quality. While total quality moves from an emphasis on historical practices such as inspection, sorting and rework to an emphasis on prevention, TPM moves from an emphasis on simple repair to a primary focus of the prevention of machinery breakdown before it occurs (Robertson and Niehaus, 1992). A complete definition of TPM includes the following five elements (Nakajima, 1988): 1. TPM aims to maximize equipment effectiveness (overall effectiveness). 2. TPM establishes a thorough system of PM for the equipment’s entire life span. 3. TPM is implemented by various departments (engineering, operations, and maintenance). 4. TPM involves every single employee, from top management to workers on the floor. 5. TPM is based on the promotion of PM through motivation management: autonomous small group activities. The major thrust of TPM is to maximize equipment effectiveness. With any process or program, to determine the success, there needs to be metrics to track the progress. Maximizing equipment effectiveness is a key element of overall plant effectiveness. There are eight major losses to the plant that hinder a plant from achieving its maximum effectiveness. They include the following: 1. Shutdown loss is time lost when production stops for planned annual shutdown maintenance or periodic servicing. 2. Production adjustment loss is time lost when changes in supply and demand require adjustment in production plans. 3. Equipment failure loss is time lost when a plant stops because equipment suddenly loses its specified functions. 4. Process failure loss is time lost when a plant shuts down as a result of factors external to the equipment, such as operating errors or changes in the physical or chemical properties of the substances being processed. 5. Normal production losses are rate losses that occur during normal production at plant startup, shutdown, and changeover. 6. Abnormal production losses are rate losses that occur when a plant performs inadequately as a result of malfunctions and other abnormal conditions that interfere with performance. 7. Quality defect losses include time lost in producing rejectable product, physical loss in scrap, and financial losses due to product downgrading. 8. Reprocessing losses are recycling losses that occur when rejected material must be returned to a previous process to make it acceptable (Suzuki, 1994) These losses can have a serious financial impact on the company. It is essential to minimize these losses and prevent their occurrence. These losses, if significant, could have a detrimental impact on the continuing existence of the company. Loss of customers is hard to quantify other than a reduction of sales and lost future sales. Measuring the success of the TPM program is important. There are several key measures that can assist in tracking progress during implementation of TPM. These measures include measuring availability which takes into consideration operation time and loading time where operation time is defined as loading time less downtime (Nakajima, 1988). A metric can be established to compare actual performance. The key to successful performance measurement is accuracy. If the information is not accurate, the metric will be bogus and will not provide meaningful information. Another measure identified by Nakajima is the performance efficiency. This compares theoretical cycle time with actual cycle time. Additionally, he defines a third measure referred to as rate of quality products. The three measures; availability, performance efficiency, and rate of quality products multiplied by each other gives the key metric of overall equipment effectiveness (Nakajima, 1988). This metric measures the success of TPM. Preventive plant maintenance aims to control planned maintenance activities instead of allowing machine breakdowns, which result in unexpected expenses. Studies show the good preventive maintenance practice will reduce maintenance costs by 30% when compared to expenses incurred from reactive maintenance. In addition, good plant maintenance will result in improved production capacity, thus, boosting the plant’s bottom line profit (Brautigam, 1993). Because there are numerous constraints involved in implementing TPM, the use of linear programming models may be useful to properly consider all the constraints and limitations. Another statistical technique that could aid in evaluating the constraints associated with TPM implementation is goal programming. Goal programming would take into consideration setup time, profit goals, cost savings, capacity constraints, production objectives, product mix, and inventory issues. Since Ford Motor Company is quite large; the development of statistical models would be quite complex to ensure that all variables have been properly included in these models to calculate a meaningful result. TPM Today The TPM process needs to start with the requirements for the equipment to be purchased. Equipment Maintenance Council executive director Jack Mears (1996) says that equipment breakdowns can be prevented by adopting a PM program. PM, which stands for planned maintenance, programmed maintenance, and preventive maintenance involves the identification of mechanical problems before these affect production. Mears (1996) also says that function rather than price should be the main consideration in equipment selection. In the automotive industry where the lowest price gets the highest consideration, the lowest price does not always mean the lowest cost. As companies focus on cost reduction efforts, there is a need to properly evaluate the equipment purchases and this may require paying a price greater than the “lowest bid price” to achieve overall lowest life cycle cost. Companies who continue to purchase equipment at the lowest price are living for the short-term and not properly planning for the future profitability. Short-run decisions such as these have focused on today’s profit and not tomorrow’s cost. Once the equipment has been purchased, the key focus is on maximizing machine effectiveness. Maintaining productivity involves balancing many factors including operator training, equipment maintenance, quality control and production scheduling. Cross-training of operators helps maintain productivity even when a key operator is missing. Preventive maintenance is essential but should be flexibly scheduled. The quality of raw materials directly impacts productivity by contributing to machine downtime and production re-runs. Production should be scheduled based solely on what materials are currently available. Total Productive Maintenance affects the entire business. It affects human resources and requires that proper training and change management is addressed. It impacts productivity and output, which could have an impact on the customer. It affects the entire supply chain from supplier to customer. As mentioned earlier, TPM is linked to many continuous improvement initiatives. A new approach is presented using theory of constraints (TOC). TOC focuses on the company’s goal and how to achieve such a goal. It does not focus on cost reduction like many other improvement programs. Rather, it seeks to increase the level of manufacturing (Chakravorty and Atwater, 1994). The Ford Motor Company supports the Theory of Constraints (TOC) philosophy which focuses on increasing the level of production which ultimately will decrease cost and increase profitability. Autonomous maintenance is also a significant element in TPM. Autonomous maintenance activities are one of the main features of TPM, and are a key point in its development. Changing the lack of interest in maintenance on the part of operators, who think that “I’m the operator, and you’re the maintenance man”, and developing autonomous maintenance-i.e. “autonomously maintaining the equipment one uses by oneself” – is not something that can be done overnight. It takes two to three years from when TPM begins to be introduced up until the introduction stage is fully implemented, and this is because it takes time to change the attitude of human beings (Nakajima, 1986). In a union environment it requires receiving a buy-in from the union to modify work rules and therefore move to flexible job classifications. This is a big barrier in the automotive industry. It also requires cross training of the employee to provide them with the technical tools necessary to allow for autonomous maintenance. The main goal of an effective TPM effort is to bring critical maintenance skilled trades and production workers together (Labib, 1999). This effort is not always an easy one. Many issues arise as this foundational effort is undertaken. The role of the worker is changed from the traditional craft mentality to the removal of barriers that have been in place since auto production started (McAdam and Duffner, 1996). This effort requires an "Active Organization" (Yamashina, 2000). This requires competent leaders that are willing to invest in education and willing to empower the workers. As TPM is a common element to the lean drive, it requires not only flexible equipment but employees involved in the production process (Sahin, 2000). Many issues arise when trying to implement TPM in a union environment. Workers fear that the only drive is to improve production efficiency, reduce labor, and increase employee work load (McAdam and Duffner, 1996). Many operators don't want additional responsibility and are happy with the situation the way it is. In addition the skilled trades enjoy their indispensable role and feel that the autonomous maintenance activity threatens their jobs (Patterson, et. al, 1995). TPM and the Future Moving forward, as there is movement to what is known as the knowledge-value society, knowledge workers will constitute a significant part. One aspect of this knowledge-value revolution is the emphasis on man-made resources as capital goods and other goods of heavy technological content. TPM is a critical part of the strong technology base for “man-made resources” (Banker, et al., 1996) The value of TPM cannot be realized or maximized if the following does not occur: (1) cost savings from TPM can be predicted and measured, (2) cross-functional teams are integrated to enhance the value of TPM, and (3) the root cause of equipment problems is effectively identified (Leblanc, 1995). This goes back to the earlier discussion regarding the importance of identifying metrics to track progress. TPM goals and objectives need to be fully integrated into the strategic and business plans of the organization because TPM affects the entire company and is not limited to production. Improvement in equipment striving for the optimal conditions leads to zero breakdowns, and zero breakdowns lead to zero defects. Striving for zero defects target leads to significant cost reduction, which in turn provides the needed cost and quality to protect investment and jobs in the future. This is the Total Productive Maintenance reaction (Banker, 1995). This supports the philosophy and methodology that the Japanese profess to when it comes to successful implementation of TPM. As the TPM process is implemented, maintenance cost will be reduced as the quality of the product manufactured is improved (Koelsch, 1993). Automation integration is important and is the way of the future for any manufacturing initiatives including TPM. Early warning is a key to total equipment failure. Hazard studies, expert systems, failure mode and effects analysis (FMEA) or PFMEA (Process FMEA), root cause and fault tree analysis, and condition monitoring give early warning of impending failure. Equipment designs emphasizing reliability and maintainability (R & M) attack causes (Owen, 1994). These methods have been used for many years by industries outside of automotive and in the past few years, the automotive industry has realized the benefits