1. Breakdown maintenance:
In this type of maintenance, no care is taken for the machine, until equipment fails. Repair is then undertaken. This type of maintenance could be used when the equipment failure does not significantly affect the operation or production or generate any significant loss other than repair cost. However, an important aspect is that the failure of a component from a big machine may be injurious to the operator. Hence breakdown maintenance should be avoided.
2. Preventive maintenance:
It is a daily maintenance (cleaning, inspection, oiling and re-tightening), design to retain the healthy condition of equipment and prevent failure through the prevention of deterioration, periodic inspection or equipment condition diagnosis, to measure deterioration. It is further divided into periodic maintenance and predictive maintenance. Just like human life is extended by preventive medicine, the equipment service life can be prolonged by doing preventive maintenance.
2a. Periodic maintenance (Time based maintenance - TBM):
Time based maintenance consists of periodically inspecting, servicing and
cleaning equipment and replacing parts to prevent sudden failure and process
problems. E.g. Replacement of coolant or oil every 15 days.
2b. Predictive maintenance:
This is a method in which the service life of important part is predicted based
on inspection or diagnosis, in order to use the parts to the limit of their
service life. Compared to periodic maintenance, predictive maintenance is
condition-based maintenance. It manages trend values, by measuring and analyzing
data about deterioration and employs a surveillance system, designed to monitor
conditions through an on-line system. E.g. Replacement of coolant or oil, if
there is a change in color. Change in color indicates the deteriorating
condition of the oil. As this is a condition-based maintenance, the oil or
coolant is replaced.
3. Corrective maintenance:
It improves equipment and its components so that preventive maintenance can be carried out reliably. Equipment with design weakness must be redesigned to improve reliability or improving maintainability. This happens at the equipment user level. E.g. installing a guard, to prevent the burrs falling in the coolant tank.
4. Maintenance prevention:
This program indicates the design of new equipment. Weakness of current machines is sufficiently studied (on site information leading to failure prevention, easier maintenance and prevents of defects, safety and ease of manufacturing). The observations and the study made are shared with the equipment manufacturer and necessary changes are made in the design of new machine.