Table of Contents

What is Preventive Maintenance | Objective , Procedure , Advantages

What is Preventive Maintenance :

It is a method of maintenance aimed at avoiding or preventing breakdowns. The principle of preventive maintenance is ‘Prevention is better than cure’
Here some components are identified as weak spots in all machineries and equipments. These parts are inspected regularly. Minor repairs are carried out immediately as soon as there is necessity. This reduces the unanticipated breakdowns.

Objectives Of preventive Maintenance :
1. To minimize the possibility of unanticipated break downs
2. To make plant and machines always available for ready use.
3. To retain the value of the equipment
4. To maintain optimum productivity
5. To maintain the accuracy of the machineries
6. To reduce work content during maintenance
7. To ensure safety to workmen

Procedure Of Preventive Maintenance

1) Maintaining machine Records

To carryout the preventive maintenance effectively all the details about the machines should be kept in records.

These are
a) Type of equipment and description
b) Name of the manufacturer
c) Cost and date of the purchase
d) Cost and date of planned repairs
e) Breakdowns if any and their dates and reasons
f) List of spare parts and their code numbers

2) Preparing Inspection checklist

Here the components to be inspected on regular intervals are listed. i.e What are to be inspected daily/ weekly/ monthly are listed. General items which are to be inspected regularly are :
a) Material handling equipments like crane, hoists lifts conveyors trucks etc.
b) Safety equipments like relief valves, fire extinguishers, safety alarms etc.
c) Process equipments like furnaces , compressor, pumps, motors etc
d) Water, air and fuel lines
e) Key equipments and machineries

Frequency of inspection depends upon
a) Severity of work carried out on the machine – whether one shift, two shift or for 24 hrs daily.
b) Age, condition and value of the equipment
c) Safety and health environment
d) Amount of exposure to dirt, fumes, friction , fatigue , stress , corrosion, wear etc.

3. Inspection as per check list and corrective action

Inspection and corrective action can be done as follows
a) Routine up-keep adjustment of guide plates, lubrication and cleaning
b) Periodic inspection – Visual inspection – Overhauls, scheduled replacements etc.

These maintenance works are done without disturbance to the production activities. In preventive maintenance , the cost of maintenance will be high. Because many people are involved in inspection, record keeping and maintenance work. More number of spare parts Are stocked. The parts are replaced before the end of their life.

Preventive Maintenance can be broken down into the following different maintenance strategies or types:

Time Based Maintenance (TBM)
Failure Finding Maintenance (FFM)
Risk Based Maintenance (RBM)
Condition Based Maintenance (CBM)
Predictive Maintenance (PDM)

Corrective Maintenance can be broken down into the following different maintenance strategies or types:

Deferred corrective maintenance
Emergency maintenance

Advantages of Preventive maintenance

1. reduced break downs and down time
2. Lesser overtime to maintenance people
3. Grater safety to workers
4. Low maintenance and repair cost
5. Less stand –by equipment needed.
6. Reduced production cost
7. Increased equipment life
8. Increase workers morale – as no stoppage of work.
9. Better product Quality
10.Less material wastages.