Maintenance

Types and Procedures

What is maintenance?

• It is the “combination of all technical and administrative actions, including supervision actions, intended to retain an item in, or restore it to, a state in which it can perform a required function”

• Maintenance is a set of organised activities that are carried out in order to keep an item in its best operational condition with minimum cost acquired.

Is it only cleaning and washing?

Maintenance Objectives

• Reducing breakdowns and emergency shutdowns.

• Optimising resources utilisation.• Reducing downtime.• Improving spares stock control.• Optimising the useful life of equipment.

Breakdown Maintenance

• The required repair, replacement, or restore action performed on a machine or a facility after the occurrence of a failure

• The failure of a component in a system is unpredictable.

• It is the oldest type of maintenanceADVANTAGES• Complete use of material and machine• The cost of performing this type of maintenance

activities is lower than performing other types of maintenance.

Preventive Maintenance

• The maintenance carried out at predetermined intervals or according to prescribed criteria and intended to reduce the probability of failure

• It is good for those machines and facilities which their failure would cause serious production losses.

ADVANTAGES• Breakdowns and emergency repairs are minimised.• Increased component’s life• Annual production capacity can be exactly

estimated

Corrective Maintenance

• In this type, actions such as repair, replacement, or restore will be carried out after the occurrence of a failure in order to eliminate the source of this failure or reduce the frequency of its occurrence.

• Corrective maintenance is different from run to failure maintenance in that its activities are planned and regularly taken out to keep plant’s machines and equipment in optimum operating condition.

Contd...

ADVANTAGES• Maximisation of the effectiveness of all

critical plant systems• Elimination of breakdowns. • Elimination of unnecessary repair.

Design-out maintenance

• Set of activities that are used to eliminate the cause of maintenance, simplify maintenance tasks.

• Raising machine performance from the maintenance point of view by redesigning those machines and facilities which are vulnerable to frequent occurrence of failure

Opportunity maintenance

• Set of maintenance activities that are performed on a machine or a facility when an unplanned opportunity exists during the period of performing planned maintenance activities to other machines or facilities.

ADVANTAGES• Separate time for maintenance activities for

such machines need not be scheduled• Effective usage of man power and energy

Condition-based predictive maintenance

• Depends on continuous or periodic condition monitoring equipment to detect the signs of failure.

• Example : Boilers – Hairline cracks

Reliability Centred Maintenance

• It is a process used to determine the maintenance requirements of any physical asset in its operating context.

• Able to focus maintenance activities on critical components.

• Example : Nuts and bolts of ladders are of least importance when compared to baffles of large distillers.

Total Productive Maintenance

• Total Productive Maintenance (TPM) is a maintenance program which involves a newly defined concept for maintaining plants and equipment.

• The goal of the TPM program is to markedly increase production while, at the same time, increasing employee morale and job satisfaction.

Objectives of TPM

• TPM was introduced to achieve the following objectives. – Avoid wastage in a quickly changing economic

environment.– Producing goods without reducing product quality.– Reduce cost.– Produce a low batch quantity at the earliest

possible time.– Goods sent to the customers must be non

defective.

It is only the tip of the iceberg!

Procedures for Maintenance

• Maintenance Planning

• Performing Maintenance activities• Inspecting work done• Evaluating Maintenance

Quiz

• What type of maintenance does the following need?

1. Nuclear reactor2. Car manufacturing unit3. Aeroplane4. Ship

That is it!!!