Repair maintenance attempts to repair the breakdowns, while preventive maintenance attempts to prevent any probable breakdowns resulting in production stoppages. It follows a slogan that â€œprevention is better than cureâ€?. It is also said that, â€œPrevention maintenance is a stitch in time that saves nine.â€?
Prevention maintenance ensures smooth and continuous production flow. It eliminates any chances of breakdowns and industrial accidents. It controls vibration and noise transmission, and thus prevents any adverse effect on the morale of workers.
Preventive maintenance in other words is prophylactic, diagnostic or predictive maintenance, periodically carried out to reduce the probability of an equipment condition falling below a required level of acceptability. Prevention maintenance can be made while the machines are running or when they are shut down.
Prevention maintenance is carried on as under:
1. Elimination of overloading on equipment or plant services.
2. Regular cleaning, greasing and oiling of the moving parts.
3. Replacement of worn out parts before they fail to operate.
4. Periodic overhauling of the entire machine.
5. Parts or equipments which are liable to sudden failures should be installed in duplicate, e.g. pumps, transformers, compressors, motors etc.
6. For the key and critical machines, stand by (extra) machines should be provided
The preventive maintenance function is subdivided as under:
(i) Preventive maintenance of production departments:
(a) Anticipatory inspection and servicing of equipment.
(b) Routine maintenance.
(ii) Prevention maintenance of plant services.
Prevention maintenance of production departments:
Production department are directly contributing to the production operations and so the maintenance is strategic in nature. It is done as under:
(a) Anticipatory inspection and servicing of equipment: Anticipatory inspection is a time-scheduled inspection of all production departments conducted with a view to detect any wear and tear of the equipment of any plant. A predetermined schedule is prepared for the inspection of each part of the machine and equipment. Such scheduling is generally done by the plant engineer who is well conversant with the characteristic features of each machine and equipment. Generally, the inspecting and service functions are conducted during night, week-end days holidays or slacks so that the production flow may not be interrupted.
(b) Routine maintenance: The routine maintenance of the production department involves the cleaning of work-bench; cleaning, greasing and oiling of machines; tightening the bolts, recharging of batteries, replacing all the light bulbs in the plant area at some regular intervals etc. It is routine in the sense that it does not require any technicality. It is of a repetitive nature and is done more frequently than anticipatory inspection.
Prevention maintenance of plant services:
Preventive maintenance is equally important for the various types of plant services. Though they do not directly contribute to the production like other departments, they play a key role in the production operations. The important plant services requiring preventive maintenance are ground and flooring, buildings, power plant, materials handling equipment, fleet of transport vehicles, water supply, waste disposal systems, storeroom, tool room, timekeeperâ€™s office, fire fighting facilities etc.
It should be concluded that preventive maintenance is many times desirable than repair maintenance. Preventive does reduce the repairs however it cannot eliminate them because wear and tear is a common phenomenon. The time required for preventive maintenance and repairs should also be taken care of. If it takes just as long as to perform plant maintenance as it does to repair the machine, there is no advantage in plant maintenance reducing the amount of time that the machine can work.