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Maintenance, Repair, and Overhaul: A Preview

1.1 Introduction

To undertake the reliability analysis of repairable systems, most of the industries establish their own setup of maintenance, repair, and overhaul (MRO) facilities. Before we embark upon the remaining contents of the book, the authors thought it imperative to introduce the readers to the basics of maintenance, repair, and overhaul. This chapter provides a preview of the fundamental understanding of MRO so that it will be easier to assimilate the comprehension of the advanced reliability techniques to deal with repairable systems, which has been endeavored in this book.

Maintenance, repair, and overhaul, or MRO, provides life cycle maintenance through routine preventive maintenance, planned out-of-service maintenance, or (corrective) repairs, overhaul, or rebuilds for damaged equipment. Even though industries account for the majority of them, a product or piece of equipment with high costs and a long lifespan is definitely a candidate for MRO services. Examples include massive manufacturing machinery, electric power generation, marine boats and infrastructure, mass transit vehicles, military vehicles, and systems.

Industrial systems generally deteriorate over time due to use and exposure to environmental factors. This deterioration eventually results in system failure, which in turn causes safety problems, equipment damage, quality problems, and unplanned machine downtime. A few decades ago, maintenance was mainly thought of as something challenging to manage and had to be done after a failure. Maintenance is widely acknowledged as a crucial component of asset management and a crucial commercial function. Organizations are becoming more aware of how maintenance intervention planning may increase their productivity and reliability. Preventive maintenance activities increase as a result and better fit with other business processes like production scheduling and spare parts management. For instance, companies in the process and chemical sectors can significantly boost profitability by preventing unscheduled stoppages. The continuous automation of production processes and an intensifying level of competition in the market have increased awareness of the need for good maintenance planning.

Keeping facility equipment, tools, and infrastructure in good condition and operating them efficiently is the objective of anybody who works in maintenance. This helps to prevent unanticipated downtime or equipment failure. This is what repair and maintenance allow us to do. Although the terms repair and maintenance are sometimes used interchangeably, they have various meanings in the asset management industry. When an asset breaks, is damaged, or ceases to function, repairs are restorative work that must be done. Routine tasks and/or corrective or preventive repairs performed on assets to avoid damage and extend life expectancy are referred to as maintenance. Examples include routinely cleaning grease traps, and air conditioning units, painting, and inspections.

An overhaul is a general maintenance procedure carried out on a piece of machinery or other industrial equipment. The purpose of an overhaul is to maintain the system's function. Regular inspections can stop a variety of critical damage. Typically, maintenance service providers carry out machinery overhauls. It is possible to agree on the frequency of overhauling; regular maintenance is typically planned for once a year. A more frequent equipment check is advised for older machinery, especially larger ones with complicated mechanics. Typically, overhauls begin with a thorough inspection. The overhauled machine is examined by skilled maintenance personnel. It indicates that the machine's operation is tracked while it is in use. The item of equipment should be disassembled following the initial inspection. For additional inspection and the subsequent overhauling stages, such as repair, disassembly is essential. An efficient machine breakdown by a trained maintenance technician can reveal which equipment components require replacement or repair. The machine is either fixed or certain damaged parts are changed, depending on the problem. This procedure demonstrates once more how efficient overhauling is compared with complete equipment replacement.

Since the spare parts may need to be acquired from a manufacturer, part replacement may require more time than a straightforward repair. Reassembling the entire mechanism is done after the successful substitution of spare parts. The reassembly, which comes last, is essential to the equipment's operation. Reassembly requires a certain level of competence; therefore, it is best left to the experts. It is difficult to determine whether a repair was successful without testing. Testing determines if the reassembly is successful or not; otherwise, the procedure restarts at the beginning (inspection).

In the further section, a brief understanding of the maintenance, repair, and overhaul is provided for the benefit of the readers, and the same is further amplified in the next chapter as per the subject covered in subsequent chapters.

1.2 Maintenance

Maintenance is an essential integral of any organization. It is far beyond just fixing a failed system. It is an investment for the future and guarantees that the system will continue to perform reliably. It is defined as "Maintenance is a philosophy to utilize all physical sciences with a disciplined manner at all levels of the operation, which assures that critical capital asset will provide long-term and reliable performance." Taking such a narrow perspective, maintenance activities will be confined to the reactive tasks of repair actions or item replacement triggered by failures. Thus, this approach is known as reactive maintenance, breakdown maintenance, or corrective maintenance. "All operations aimed at keeping an object in, or restoring it to, the physical state considered necessary for the performance of its production function" is how Geraerds (1983) described maintenance in a more modern context. Of course, proactive actions like routine maintenance, periodic inspections, preventive replacements, and condition monitoring are also included in the scope of this expanded view.

Depending on how duties are distributed within the business, these maintenance activities may be split among different departments. For instance, in a company that uses total productive maintenance (TPM), the maintenance department handles significant repairs and overhauls, while the operating staff is in charge of routine service and periodic equipment inspection (Nakajima, 1988). The actual maintenance procedure may be exclusive to a particular facility, industry, or collection of issues. Identical product organizations may use different maintenance systems with varying levels of technological development and production size, and the various systems may function effectively. As a result, maintenance systems are created employing formal decision-making tools and processes along with experience and judgment. However, two important factors should be taken into account: a strategy that determines which level of the plant to perform maintenance on, thus outlining a structure that will support the maintenance, and second, planning that deals with daily decisions on what maintenance tasks to perform and providing the resources to carry out these tasks. One of the fundamental and essential elements of the maintenance is the maintenance management function (MMF). According to Figure 1.1 below, the MMF entails organizing, planning, controlling, and implementing maintenance activities.

There are significant factors that must be taken into account while designing the maintenance organization. The factors to consider are maintenance capacity, centralization versus decentralization, and insourcing versus outsourcing maintenance. The following aspects or factors significantly impact a maintenance organization's role within the plant or the entire organization:

• Type of business: such as whether it is labor-intensive, high-tech, producing goods, or providing services.
• Goals: These could include things like maximizing profits, expanding market share, and other industries' goals.
• Size and organizational structure.
• Organizational culture and the scope of the maintenance responsibilities assigned.

Figure 1.1 Activities in maintenance management function.

Maintenance expenses make up a sizeable amount of operating expenses for many asset-intensive enterprises. In larger businesses, a $1 million reduction in maintenance costs generates the same amount of profit as a $3 million increase in sales (Wireman T, 2007). Around 1,500 billion euros are spent annually on Europe's maintenance budget (Altmannshoffer R, 2006) and 20 billion euros per year for Sweden (Ahlmann H, 2002). In opencut mining, a typical dragline's loss of revenue ranges from US $0.5 to US $1 million per day. A 747 Boeing plane's loss of revenue ranges from US $0.5 to US $1 million per day (Murthy, Atrens, and Eccleston, 2002). As a result, business management is increasingly aware of the value of maintenance productivity.

Here are a few instances where inadequate maintenance procedures led to catastrophes and accidents that resulted in significant losses, including Bhopal, Piper Alpha, the Columbia space shuttle, and power outages in 2003 in New York, the UK, and Italy. Instead of saving a billion US dollars, such an accident may have been avoided and improved the organization's reputation. Maintenance performance...