MAINTENANCE : MAINTENANCE Prepared By
GM ( Facility & Services )
E-City Bioscope Entertainment Pvt Ltd
An ESSEL Group Enterprise What is Maintenance : What is Maintenance The activity carried out to prevent the occurrence of failure and activity carried out after failure to rectify the defect is called maintenance. Objective of Maintenance : Objective of Maintenance The primary objective of maintenance is to increase the operational reliability and personnel safety at minimum cost.
Failures are inevitable due to natural wear and tear. Why Maintenance Required : Why Maintenance Required Plant and machines in any organisation is expected to run continuously without any interruption during the production period.
Interruptions are frequently felt on account of machine break downs due to failures of machine parts / components.
There is always some loss of production on account of machine failure. Production Vs Maintenance : Production Vs Maintenance The total production that can be obtained from a plant depends upon its capacity and the number of working hours. Interruption on account of breakdown reduce the total time available for production. Therefore
Production = Capacity x Availability. Down Time : Down Time The duration by which any machine goes out of production due to break down is called down time.
The down time is the total time taken on account of maintenance to rectify the fault.
The total time taken on account of maintenance involves the time actually spent by the respective maintenance team to correct the fault and waiting time for want of spares required for rectify the defect.
Down time = Repair time + waiting time Waiting Time : Waiting Time The waiting time is the most unproductive elements of total down time . The reason for waiting time could be :-
Want of spares
Want of crew members
Lack of communication.
Lack of proper supervision Total Down Time : Total Down Time MAINTENANCE Role of Maintenance : Role of Maintenance Maintenance play an important role in a manufacturing activity where plants and machineries are employed. No machine can work indefinitely and produce continuously . There is going to be some interruptions in production due to machine failures. At the same time higher the number of failures greater will be the loss of availability and production. Role of Maintenance : Role of Maintenance The frequent failures cause frequent interruption in the production and the plant and machines become unreliable. This degree of uncertainty in production due to machines failures is termed as reliability .
Higher the reliability in operation lesser will be the failure or vice versa. Mean Time Between Failure ( MTBF) : Mean Time Between Failure ( MTBF) This is the average time a machine can operate without the occurrence of any failure.
MTBF indicates the operational reliability of the machine. Higher the value of MTBF, higher will be the operational reliability of the machine because of lesser number of failures. Mean Time Between Failure ( MTBF) : Mean Time Between Failure ( MTBF) To improve the operational reliability , the number of failures should be reduced. Failures can be reduced if the machines are maintained properly with adequate care and attention.
Failures can reduce by better maintenance. Need OF Maintenance : Need OF Maintenance Need of maintenance arise for two reasons.
To prevent the occurrence of any possible failures.
To correct a failures in a shortest possible time. Type of Maintenance : Type of Maintenance There is two type of maintenance.
Break down / corrective maintenance. Preventive Maintenance : Preventive Maintenance The activities which are carried out to prevent the occurrence of failures are known as preventive maintenance.
Preventive maintenance is further divided in two parts.
Indirect maintenance. Direct Preventive Maintenance : Direct Preventive Maintenance Direct preventive maintenance activities are such as cleaning, lubricating , replacement of wear/ tear parts and overhauling of machine. Most of the common failures which are likely to occur during running of machinery can be arrested. This can not give 100% operational reliability. Because there is always chances of unexpected failures to occur. Indirect Preventive Maintenance / Condition Monitoring : Indirect Preventive Maintenance / Condition Monitoring By constantly monitoring the observable characteristics any major faults / failures that is being gradually developed can be detected before hand.
This constant monitoring of observable characteristics and measurable parameters in any plant and machinery is called “condition Monitoring.”
Indirect preventive maintenance helps to take corrective action in planned manner by giving the reports as and when parameters changes sharply. Break Down / Corrective Maintenance : Break Down / Corrective Maintenance The activity which are carried out after the occurrence of failures to correct the failures are known as corrective maintenance. Slide 19: Maintenance Corrective Preventive Unplanned Planned Break Down Correct/Rectify
Faults Indirect Direct Conditioning
Overhauling Failure Reports