IntroductionThe Oxford dictionary meaning of “to maintain” is to “cause something to continue” or “to keep something in existence at the same level”.“Maintenance is the process of maintaining an item in an operational state by either preventing a transition to a failed state or by restoring it to an operational state following failure”
IntroductionMaintenance engineering is typically defined as a staff function whose prime responsibility is to ensure that maintenance techniques are effective, equipment is designed and modified to improve maintainability, ongoing maintenance technical problems are investigated, and appropriate corrective and improvement actions are taken.
Purpose of MaintenanceThe purpose of maintenance is to produce reliable plant capacity. The company vision for producing a profitable product should understand that effective maintenance provides reliable plant capacity. Some of the most important maintenance decisions are made before a company even builds a plant.
Purpose of MaintenanceGifford Brown (1993) of Ford Motor Company explains the 1-10-100 Rule. This rule means that every $1 spent up front during engineering to reduce maintenance eliminates a later $10 cost to maintain equipment properly or $100 in breakdown maintenance.
Purpose of MaintenanceIt means that every company has to maintain operable with due efficiency and effectiveness of its fixed assets. Encompasses all activities necessary for: - Maintain a facility or equipment in operation -Reset the operation of equipment to original condition. The maintenance impact, therefore, the quantity and quality of production.
Responsibility of the Maintenance The principal responsibility of maintenance is to provide a service to enable an organization to achieve its objectives. The specific responsibilities vary from one organization to another; however they generally include the following according to Duffuaa et al. (1998): 1. Keeping assets and equipment in good condition, well configured and safe to perform their intended functions; 2. Perform all maintenance activities including preventive, predictive; corrective, overhauls, design modification and emergency maintenance in an efficient and effective manner; 3. Conserve and control the use of spare parts and material; 4. Commission new plants and plant expansions; and
“Maintenance Philosophy”Based on the timing and the work contents involved in the maintenance task, different maintenance philosophies can be put in the following categories, viz.:
“Maintenance Philosophy”1. Timing known, content known: preplanned maintenance (PPM), planned shutdowns, routine inspections, and scheduled change- outs fall in this category;
“Maintenance Philosophy”2. Timing known, content unknown: statutory surveys, third party inspections, and condition-based maintenance;
“Maintenance Philosophy”3. Timing unknown, content known: anticipated maintenance work, contingency work awaiting shutdown, and run to destruction; and
“Maintenance Philosophy”4. Timing unknown, content unknown: break-down maintenance, immediate repairs arising from inspection, and run to failure.
Maintenance Scope Changed with TimeIn recent times, there has been tremendous growth in maintenance concepts and techniques. The change in emphasis includes: Decision support tools, such as hazard studies, failure modes and effects analyses, and expert systems. New maintenance techniques such as condition monitoring or CMMS. Designing equipment with emphasis on reliability and maintainability. A major shift in organizational thinking towards
Approaches to MaintenanceThere are several approaches to maintenance, and different approaches are applicable based on the expected use and maintenance schedule of an item.Economic considerations are tightly related to maintenance and the system lifecycle; it is clear that failure to consider a design’s effects on maintenance, and vice versa, can have adverse effects on profit.
Approaches to MaintenanceMaintenance has been categorized based on the nature and purpose of the maintenance work and on its frequency. Generally, there are four (basic) types of maintenances in use, viz., preventive, corrective, predictive, and fault-finding.
Approaches to MaintenanceMaintenance can also be classified according to the degree to which the maintenance work is carried out to restore the equipment relative to its original state. This leads to the following categorization: Perfect maintenance is maintenance which restores the equipment to as good as new condition.
Approaches to Maintenance Minimal maintenance results in equipment having the same failure rate as it had before the maintenance action was initiated. This is also called the as bad as old state. Imperfect maintenance is maintenance in which the equipment is not restored to as good as new, but to a relatively younger state (a state in between as good as new and as bad as old).
Approaches to Maintenance Worse maintenance: This type of maintenance results (unintentionally) in an increase of the equipment’s failure rate or actual age but does not result in breakdown. Worst maintenance: This type of maintenance results (unintentionally) in the equipment’s breakdown.