Types of Maintenance, Advantages, and Disadvantages.

Objectives of Maintenance:

  • Increase the availability of equipment to the level of accuracy.
  • Reduce costs to the minimum compatible with the level of required availability.
  • Improve the reliability of machinery and installations.
  • Assistance to the engineering department in new projects to facilitate the maintainability of the new facilities.

                      Maintenance objectives

Types of maintenance:

Any productive company that handles machinery and equipment, to perform optimally should have a type of maintenance defined according to the production activity. Then we list the different types of maintenance and shown in the figure below.

Planned maintenance-Corrective or Proactive.

Corrective maintenance is a process that is carried out in order to repair faults that occur in the machinery or equipment.

It is a most basic form of maintenance as it simply involves repairing what has broken down. It is the process of locating and correcting breakdowns that are preventing equipment to perform its function normally.


  • It does not require a large technical setup or high analytical capacity.
  • Corrective maintenance maximizes the use of the equipment’s useful life.


  • Disturbance to production takes place due to unexpected faults.
  • Risk of failure of elements that are difficult to acquire, which implied the need for an important spare parts stock.
  • Low quality of maintenance as a consequence of the little time available for repair.


  • When the total cost of the stops caused is less than the total cost of the preventive actions.
  • This only occurs in secondary systems whose failure does not significantly affect production.
  • Statistically, it turns out to be the one applied in the highest proportion in most of the industries.

Planned maintenance-Preventive:

Preventive maintenance was designed with the idea of anticipating and anticipating the failure of machines and equipment. It is carried out by using a series of data on the different systems and subsystems and even parts.

In this type of maintenance, periodic, cyclical, and programming, for which a program is designed with calendar frequencies. This is to make changes of parts, changes of sub-assemblies, repairs, adjustments, oil and lubricant changes, in order to allow a longer as well as continuous operating time.

It is intended for a particular area and for certain teams specifically.


  • Reduces failures and downtime. That is, it increases the availability of equipment and facilities.
  • Improves the use of resources
  • Action is taken on the origin of the fault.
  • It allows the company to have a history of all the equipment, also provides the possibility of updating the technical information of the equipment.
  • Reduce inventory levels.
  • It allows having a budget approved by the board of directors.
  • Improves the life of equipment and facilities.


  • Experience and technical capacity of maintenance personnel are required as per the manufacturer’s recommendations to make the maintenance schedule for the equipment.
  • It does not allow to determine exactly the wear or decrease of the parts of the equipment.
  • The infrastructure represents a considerable initial investment.
  • The labor used in this type of maintenance must be qualified, for hence its cost increases.
  • Components are replaced based on the average lifetime of the ports, wasting a useful life that can belong.

Unplanned maintenance-Predictive maintenance:

This type of maintenance is based on predicting the failure before it occurs. Try to get ahead of the failure or the moment the equipment stops working in its optimal conditions.

To achieve this, it is diagnosed based on the analysis of parameters (vibration, infrared radiation, supply voltages, and currents), which machines emit without them stopping producing.

Predictive maintenance is classified into two, one is condition-based monitoring (BM), and the other is reliability-centered monitoring (RCM).

Condition Based Maintenance (CBM): It is a maintenance approach that monitors the real-time status. Performance degradation is studied by visual inspection, performance data, and scheduled tests. Condition-based maintenance (CBM) is performed only after noticed a decrease in the performance of the equipment.

Reliability Centered Maintenance (RCM): RCM is used to identify all possible causes of a system failure using cause and effect relationships. All failure modes are identified. All the possible ways in which equipment, machinery, or a system can fail and the different possibilities.

It is a very powerful, widely used methodology that, when applied correctly, can lead to significant improvements in equipment reliability and shop floor performance.

Predictive maintenance consists of:

Analysis: Study of characteristics fundamentals, and potential failure modes.

Normalization: Translate the failure modes to predictive parameters of supervision. Assign the corresponding acceptance limits or alarms.

Systematization: Necessary steps in case of eventuality that a parameter exceeds its alarms values. Configuration of diagnosis, evaluation, action.


  • Reduces downtime by knowing exactly which organ is failing.
  • It allows following the progress of a defect over time.
  • Optimizes the management of maintenance personnel.
  • Requires a smaller maintenance staff.
  • Verification of the status of the machinery, both carried out periodically and accidentally, allows you to create a historical file of the behavior very useful mechanical, and operational in these cases.
  • It allows knowing exactly the time limit for action that does not imply the development of an unforeseen failure.
  • It allows making decisions about stopping a line of machines in moments of critics.
  • Guarantees the preparation of internal form of operations or purchases of the new team.


  • The implementation of such a system requires a significant initial investment, fault detection equipment. Ex: Vibration analyzers, high cost involved.
  • Qualified personnel must be assigned to carry out the periodic reading of data in the equipment to be used.
  • It is justified in machines or installations where untimely shutdowns cause high losses, where unnecessary downtime results in high costs.

Author: PSS Bapu Rao

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