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Maintenance, repair, and operations (MRO) involves fixing any sort of mechanical, plumbing, or electrical device should it become out of order or broken (known as repair, unscheduled, casualty or corrective maintenance). In the aircraft maintenance market sector, maintenance, repair and overhaul (MRO) services also include inspection, rebuilding, alteration and the supply of spare parts, accessories and raw materials, adhesives, sealants, coatings and consumables for aircraft manufacturing and MRO.
Contents
In all sectors, effective MRO involves performing routine actions which keep devices, equipment, machinery, building infrastructure and supporting utilities in working order (known as scheduled maintenance) and prevent trouble from arising (preventive maintenance).
The marine transportation, offshore structures, industrial plant/equipment and commercial facilities market sectors depend on scheduled or preventive paint maintenance programmes to maintain and restore coatings applied to steel, and also concrete and masonry assets in environments subject to attack from erosion, corrosion and environmental pollution.
MRO can be categorised by whether the product remains the property of the customer (i.e. a service is being offered), or whether the product is bought by the reprocessing organisation and sold to any customer wishing to make the purchase (Guadette, 2002). In the former case it may be a backshop operation within a larger organization or smaller operation.
The former of these represents a closed loop supply chain and usually has the scope of maintenance, repair, or overhaul. The latter of the categorisations is an open loop supply chain and is typified by refurbishment and remanufacture. The main characteristic of the closed loop system is that the demand for a product is matched with the supply of a used product. Neglecting asset write-offs and exceptional activities the total population of the product between the customer and the service provider remains constant.
Engineering
In telecommunication, commercial real estate and engineering in general, the term maintenance has the following meanings:
Manufacturers and industrial-supply companies often refer to MRO as opposed to original equipment manufacturer (OEM). OEM includes any activity related to the direct manufacture of goods, where MRO refers to any maintenance, repair or overhaul activity to keep a manufacturing plant or facility running. Maintenance is strictly connected to the stage of ideation, in which the concept of maintainability must be included. In this scenario, maintainability is considered as the ability of an item, under stated conditions of use, to be retained in or restored to a state in which it can perform its required functions, using prescribed procedures and resources. Overhaul extends to the concept of improving performance over and above original design specification.
Maintenance types
Generally speaking, there are two types of maintenance in use:
Architectural conservation is another type of maintenance involving the preservation, rehabilitation, restoration or reconstruction of historical structures made from stone, brick, glass, metal, and wood with MRO materials which match the original constituent materials where possible, or with suitable polymer technologies.
Preventive maintenance
Preventive maintenance is maintenance performed with the intent of avoiding failures, safety violations, unnecessary production costs and losses, and to conserve original materials of fabrication. The effectiveness of a preventive maintenance schedule depends on the RCM analysis which it was based on, and the ground rules used for cost efficacy.
Corrective maintenance
Corrective maintenance of equipment after equipment break down or malfunction is often most expensive – not only can worn equipment damage other parts and cause multiple damage, but consequential repair/replacement costs and loss of revenues due to down time during overhaul can be significant. Rebuilding and resurfacing of equipment and infrastructure damaged by erosion and corrosion as part of corrective or preventive maintenance programmes, where conventional processes such as welding and metal flame-spraying are inapplicable, may require engineered solutions with industrial polymeric materials.