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Top1. Introduction
As a successor to the Total Quality Management (TQM) paradigm, Total Productive Maintenance (TPM) is now a prominent paradigm driving manufacturing improvements in a number of Japanese industries, particularly the semiconductor industry. TPM also has gained a foothold in some American companies. While TQM's immediate focus is on efforts to perfect product quality, TPM's immediate focus is on efforts to perfect equipment productivity. Strategies under the TPM paradigm include increasing equipment knowledge within the manufacturing workforce, improving maintenance procedures, changing procedures to reduce or eliminate setups, test procedures and idle time, making modifications to increase machine speed or reduce scrap and rework, etc (Leachman, 1997). Overall equipment effectiveness (OEE) is the primary measure used in Total Productive Maintenance (TPM) to identify and quantify the major equipment-related losses and a metric for rating equipment effectiveness. OEE has become widely used in many plants with or without the elements of TPM in place since the early years of TPM to quantify equipment effectiveness losses. The early Toyota Production System focused on eliminating waste to reduce cost. OEE was initially developed to identify the major losses in equipment performance and reliability. TPM then became a company-wide approach to eliminating the major equipment losses (Swanson, 2001). The goal of TPM is to maximise equipment effectiveness and maximize equipment output (Waeyenbergh & Pintelon, 2002). In SEMI’s definition of OEE (SEMI E79, 2000) the components of the OEE are described as follows:
OEE = Availability Efficiency * Performance Efficiency * Quality Efficiency
The well-known OEE includes the multiplication of availability, performance efficiency, and rate of quality (SEMATECH, 1995). The true overall equipment efficiency of a machine is the multiplication of equipment output efficiency with the equipment input efficiency. OEE is only the output side of the equipment efficiency. Another goal of TPM as stated by Schippers (2001) is to reduce and to control the variation in a process.
TPM as defined by Nakajima (1988) is productive maintenance involving total participation'. The goal of TPM is to enhance equipment effectiveness and maximize equipment output. It strives to attain and maintain optimal equipment conditions in order to prevent unexpected breakdowns, speed losses, and quality defects in process. Overall efficiency, including economic efficiency, is achieved by operating at optimal conditions through the life of equipment, i.e., by minimising life cycle cost (LCC). A complete definition of TPM includes the following five element and activities (Chand and Shirvani, 2000):
- 1.
TPM aims to maximise equipment effectiveness (overall efficiency);
- 2.
TPM establishes a thorough system of PM for the equipment’s entire life span;
- 3.
TPM is implemented by various departments in a company;
- 4.
TPM involves every single employee, from top management to workers on the shop floor;
- 5.
TPM is based on the promotion of PM through motivation management involving small-group activities.
The concept of just in time production (JIT) strongly requires a stable assembly cell where the downtime can be predicted and plan. Any delay of production will cause delay in shipment thus lead to the higher cost of air shipment. Centered on the JIT production, some researchers have proposed more integrative production system concepts. For example, Schonberger, (1986), advocated the concept of world class manufacturing, which combined JIT production, total quality management (TQM), total preventive maintenance (TPM), and human resources management. Others emphasized the integration of JIT production and TQM (Harrison, 1992; Flynn et al., 1995). Monden, (1998) on the other hand described the Toyota production systems as a mixture of JIT production on the shop floor, human resources management, TQM, and information systems. The conceptualization of lean production by Womack et al. (1990) can be interpreted as a mechanism to harmonize designing products, purchasing parts and components, manufacturing, and marketing (Matsui, 2007)