Car maintenance

Car maintenance means to inspect the condition of car components and add (or change) expendable parts (or materials). Regular maintenance is critical to ensures the longevity and safety of a car.

The actual schedule of car maintenance varies depending on the type of a car and driving condition. Even a dealership often has a different recommended schedule from the manufacturer service manual for the same car.

Common car maintenance tasks include:

• Car wash
• check or change the engine oil and fuel filters
• inspect or replace windshield wipers
• check or refill windshield washer fluid
• inspect tires for pressure and wear.
• Tire balancing
• Tire rotation
• Wheel alignment
• check or clean battery terminals
• inspect or replace brake pads
• check or refill brake fluid
• check or refill transmission fluid
• check or refill power steering fluid
• check and refill engine coolant
• flush radiators
• inspect or replace spark plugs
• inspect or replace air filters
• inspect timing belts
• clean and adjust throttle body
• lubricate locks, latches, hinges
• check all lights and horns

Some tasks that have equivalent service intervals are combined into one single service known as a tune up

Software maintenance

In software engineering, software maintenance is the modification of a software product after delivery to correct faults, to improve performance or other attributes, or to adapt the product to a modified environment.”(ISO/IEC 14764). This international standard describes the 6 software maintenance processes as:

1. The implementation processes contains software preparation and transition activities, such as the conception and creation of the maintenance plan, the preparation for handling problems identified during development, and the follow-up on product configuration management.
2. The problem and modification analysis process, which is executed once the application has become the responsibility of the maintenance group. The maintenance programmer must analyze each request, confirm it (by reproducing the situation) and check its validity, investigate it and propose a solution, document the request and the solution proposal, and, finally, obtain all the required authorizations to apply the modifications.
3. The process considering the implementation of the modification itself.
4. The process acceptance of the modification, by checking it with the individual who submitted the request in order to make sure the modification provided a solution.
5. The migration process (platform migration, for example) is exceptional, and is not part of daily maintenance tasks. If the software must be ported to another platform without any change in functionality, this process will be used and a maintenance project team is likely to be assigned to this task.
6. Finally, the last maintenance process, also an event which does not occur on a daily basis, is the retirement of a piece of software.

There are a number of processes, activities and practices that are unique to maintainers, for example:

• Transition: a controlled and coordinated sequence of activities during which a system is transferred progressively from the developer to the maintainer;
• Service Level Agreements (SLAs) and specialized (domain-specific) maintenance contracts negotiated by maintainers;
• Modification Request and Problem Report Help Desk: a problem-handling process used by maintainers to prioritize, documents and route the requests they receive;
• Modification Request acceptance/rejection: modification request work over a certain size/effort/complexity may be rejected by maintainers and rerouted to a developer.

A common perception of maintenance is that it is merely fixing bugs. However, studies and surveys over the years have indicated that the majority, over 80%, of the maintenance effort is used for non-corrective actions (Pigosky 1997). This perception is perpetuated by users submitting problem reports that in reality are functionality enhancements to the system.

Software maintenance and evolution of systems was first addressed by Meir M. Lehman in 1969. Over a period of twenty years, his research led to the formulation of eight Laws of Evolution (Lehman 1997). Key findings of his research include that maintenance is really evolutionary developments and that maintenance decisions are aided by understanding what happens to systems (and software) over time. Lehman demonstrated that systems continue to evolve over time. As they evolve, they grow more complex unless some action is taken to reduce the complexity.

The key software maintenance issues are both managerial and technical. Key management issues are: alignment with customer priorities, staffing, which organization does maintenance, estimating costs. Key technical issues are: limited understanding, impact analysis, testing, maintainability measurement.

Software Maintenance Capability Maturity Models which address the unique processes of the software maintainers are described in the corrective maintenance maturity model (Kajko-Mattsson 2001), the IT Service CMM and to be released CMMi for Services (SEI 2008)

Software maintainer

In free and open source software, a software maintainer is usually one or more people who build source code into a binary package for distribution, commit patches, or organize code in an source repository (SVN or CVS).^[1]

Maintenance, repair and operations

Maintenance, repair and operations or maintenance, repair and overhaul (MRO) is fixing any sort of mechanical or electrical device should it become out of order or broken (repair) as well as performing the routine actions which keep the device in working order (maintenance) or prevent trouble from arising (preventive maintenance).

All actions which have the objective of retaining or restoring an item in or to a state in which it can perform its required function. The actions include the combination of all technical and corresponding administrative, managerial, and supervision actions.^[1]

Engineering

In telecommunication, and engineering in general, the term maintenance has the following meanings:

1. Any activity – such as tests, measurements, replacements, adjustments and repairs — intended to retain or restore a functional unit in or to a specified state in which the unit can perform its required functions.^[2]

2. For material — all action taken to retain material in a serviceable condition or to restore it to serviceability. It includes inspection, testing, servicing, classification as to serviceability, repair, rebuilding, and reclamation.^[3]

3. For material — all supply and repair action taken to keep a force in condition to carry out its mission.^[4]

4. For material — the routine recurring work required to keep a facility (plant, building, structure, ground facility, utility system, or other real property) in such condition that it may be continuously used, at its original or designed capacity and efficiency for its intended purpose.^[5]

Manufacturers and Industrial Supply Companies often refer to MRO as opposed to Original Equipment Manufacture (OEM). OEM includes any activity related to the direct manufacture of goods, where MRO refers to any maintenance and repair activity to keep a manufacturing plant running.

Industrial supply companies can generally be sorted into two types:

• the ones who cater to the MRO market generally carry a broad range of items such as fasteners, conveyors, cleaning goods, plumbing, and tools to keep a plant running.
• OEM supply companies generally provide a smaller range of goods in much larger quantities with much lower prices, selling materials that will be regularly consumed in the manufacturing process to create the finished item.

MRO software

In many organizations because of the number of devices or products that need to be maintained or the complexity of systems, there is a need to manage the information with software packages. This is particularly the case in aerospace (e.g. airline fleets), military installations, large plants (e.g. manufacturing, power generation, petrochemical) and ships.

These software tools help engineers and technicians in increasing the availability of systems and reducing costs and repair times as well as reducing material supply time and increasing material availability by improving supply chain communication.

As MRO involves working with an organization’s products, resources, suppliers and customers, MRO packages have to interface with many enterprise business software systems (PLM,EAM, ERP, SCM, CRM).

One of the functions of such software is the configuration of bills of materials or BOMs, taking the component parts list from engineering (eBOM) and manufacturing (mBOM) and updating it from “as delivered” through “as maintained” to “as used”.

Another function is project planning logistics, for example identifying the critical path on the list of tasks to be carried out (inspection, diagnosis, locate/order parts and service) to calculate turnaround times (TAT).

Other tasks that software can perform:

• Planning operations,
• Managing execution of events,
• Management of assets (parts, tools and equipment inventories),
• Knowledge-base data on:
  • Maintenance service history,
  • Serial numbered parts,
  • Reliability data: MTBF (mean time between failures), MTTB (mean time to breakdown), MTBR (mean time between removals),
  • Maintenance and repair documentation and best practices,
  • Warranty/guarantee documents.

Many of these tasks are addressed in Computerized Maintenance Management Systems (CMMS). Data standards have been developed around these activities, most notably EAMXML

Predictive maintenance

Predictive maintenance (PdM) techniques help determine the condition of in-service equipment in order to predict when maintenance should be performed. This approach offers cost savings over routine or time-based preventive maintenance because tasks are performed only when warranted.

Overview

PdM or condition based maintenance attempts to evaluate the condition of equipment by performing periodic or continuous (on-line) equipment condition monitoring. The ultimate goal of PdM is to perform maintenance at a scheduled point in time when the maintenance activity is most cost effective and before the equipment loses optimum performance. This is in contrast to time and/or operation count based maintenance where a piece of equipment gets maintained whether it needs it or not. Time based maintenance is labor intensive, ineffective in identifying problems that develop between scheduled inspections and is not cost effective.

The "predictive" component of the term Predictive Maintenance stems from the goal of predicting the future trend of the equipment's condition. This approach uses principles of statistical process control to determine at what point in the future maintenance activities will be appropriate.

Most PdM inspections are performed while equipment is in service, thereby minimizing disruption of normal system operations. Adoption of PdM in the maintenance of equipment can result in substantial cost savings and higher system reliability.

Reliability centered maintenance or RCM emphasizes the use of predictive maintenance (PdM) techniques in addition to traditional preventive measures.

Technologies

To evaluate equipment condition Predictive maintenance utilises Nondestructive testing technologies, such as infrared, acoustic (partial discharge and airborne ultrasonic), corona detection, vibration analysis, sound level measurements, oil analysis and other specific online tests. Vibration analysis is most productive on high speed rotating equipment and can be the most expensive part of a PdM program to get up and running. Acoustical analysis can be done on a sonic or ultrasonic level. Sonic monitoring equipment is less expensive but it also has less uses than ultrasonic technologies. Sonic technology is useful only on mechanical equipment while ultrasonic equipment can detect electrical problems and it is more flexible and reliable in detecting mechanical problems. Oil analysis is a long term program that, where relevant, eventually can be more predictive than any of the other technologies. It will take years for a plant's oil program to reach this level of sophistication and effectiveness. Infrared monitoring and analysis has the widest range of application from high to low speed equipment and it can be effective for spotting both mechanical and electrical failures. Some consider it to be currently the most cost effective technology.

Preventive maintenance

Preventive maintenance (PM) has the following meanings:

1. ,The care and servicing by personnel for the purpose of maintaining equipment and facilities in satisfactory operating condition by providing for systematic inspection, detection, and correction of incipient failures either before they occur or before they develop into major defects.
2. Maintenance, including tests, measurements, adjustments, and parts replacement, performed specifically to prevent faults from occurring.

Source: from Federal Standard 1037C and from MIL-STD-188 and from the Department of Defense Dictionary of Military and Associated Terms

While preventive maintenance is generally considered to be worthwhile, it is important to note that there are risks such as equipment failure or human error involved when performing PM, just as in any maintenance operation. PM as scheduled overhaul or scheduled replacement provides two of the three proactive failure management policies available to the maintenance engineer. Common methods of determining what PM (or other) failure management policies should be applied are; OEM recommendations, requirements of codes and legislation within a jurisdiction, what an "expert" thinks ought to be done, or the maintenance that's already done to similar equipment. However Reliability Centered Maintenance, provides the most rigorous and method to determine applicable and effective failure management policies - which may include PM tasks - for an item.

To make it simple:

• Preventive maintenance is conducted to keep equipment working and/or extend the life of the equipment.
• Corrective maintenance, sometimes called "repair", is conducted to get equipment working again.

The primary goal of maintenance is to avoid or mitigate the consequences of failure of equipment. This may be by preventing the failure before it actually occurs which PM and condition based maintenance help to achieve. It is designed to preserve and restore equipment reliability by replacing worn components before they actually fail. Preventive maintenance activities include partial or complete overhauls at specified periods, oil changes, lubrication and so on. In addition, workers can record equipment deterioration so they know to replace or repair worn parts before they cause system failure. The ideal preventive maintenance program would prevent all equipment failure before it occurs

Reliability Centered Maintenace

RCM finds its roots in the early 1960's. The initial development work was done by the North American civil aviation industry. It came into being when the airlines at that time began to realise that many of their maintenance philosophies were not only too expensive but also actively dangerous. This realisation prompted the industry to put together a series of "Maintenance Steering Groups" to re-examine everything they were doing to keep their aircraft airborne. These groups consisted of representatives of the aircraft manufacturers, the airlines and the FAA.

The first attempt at a rational, zero-based process for formulating maintenance strategies was promulgated by the Air Transport Association in Washington DC in 1968. The first attempt is now known as MSG 1 (from the first letters of Maintenance Steering Group). A refinement - now known as MSG 2 - was promulgated in 1970.

In the mid-1970's the US Department of Defence wanted to know more about the then state of the art in aviation maintenance thinking. They commissioned a report on the subject from the aviation industry. This report was written by Stanley Nowlan and Howard Heap of United Airlines. They gave it the title "Reliability Centered Maintenance". The report was published in 1978, and it is still one of the most important documents - if not the most important - in the history of physical asset management. It is available from the US Government National Technical Information Service, Springfield, Virginia.

Nowlan and Heap's report represented a considerable advance on MSG 2 thinking. It was used as a basis for MSG 3, which was promulgated in 1980. MSG 3 has since been revised twice. Revision 1 was issued in 1988 and revision 2 in 1993. It is used to this day to develop prior-to-service maintenance programs for new aircraft types.