01 principles and practices of maintenance planning

Principles and practices of Maintenance planning

Semester VIII - ME

G P Kurien

April 19, 2023Maintenance planning2

Syllabus

1. Basic Principles of maintenance planning – Objectives

and principles of planned maintenance activity –

Importance and benefits of sound Maintenance systems

– Reliability and machine availability, Equipment Life

cycle, Measures for Maintenance Performance:

Equipments breakdowns, Mean Time Between Failures,

Mean Time to Repair, Factors of availability, Maintenance

organization, Maintenance economics.


Basic Principles of maintenance planning


“Maintenance is the combination of all

technical, administrative and managerial actions

during the life cycle of an item intended to retain it in, or restore it to, a state

in which it can perform the required function”


Life Cycle Component of a Production System


Why Maintenance? 1. If an equipment can be designed, manufactured and

used in such a way that it never failed, there would be no need for preventive maintenance or for repair.

2. Similarly, if all the components of an equipment failed simultaneously, there would be no need for its repair, since the whole equipment could then be replaced.

3. Components do have a substantial failure rate, either due to deficiencies in design, or manufacture or use. Such components need to be repaired or replaced immediately to avoid the equipment remaining out of action.

4. Components have a highly variable life amongst themselves.


1. Repairs also consume time and reduce equipment availability.

2. Some design features greatly ease and thereby speed up the process of repair itself, thus diminishing the “down time” of the equipment.

3. Some design features can increase, while other features decrease the repair time dramatically


Introduction to Maintenance

1. Preserving Physical assets Vs. Preserving functions of assets.

Preserving inherent reliability. The asset should continue to do what it is expected to do. Focus on functions.

2. 1960s : Trend towards Maintenance Prevention.

3. 1970s : Change in trend due to inflation, high cost assets, competition, rapid change of technology.

Enhance useful life of equipment.

4. Maintenance is an investment.

5. Maintenance is Force multiplier.


Purpose of Maintenance

1. Reduce business risks.

2. Ensure high level of Availability Reliability Operability

3. Support end user in the various stages of equipment life cycle.

4. Ensuring safety

5. Reduce pollution/ environmental effects.

6. Cost reduction and cost control.

7. Waste reduction and waste recovery.


Basic Maintenance Functions

1. Replace2. Repair3. Overhaul4. Rebuild/

Reclamation5. Service

6. Lubricate7. Inspect8. Test / Examine9. Adjust10. Align11. Calibrate12. Install


FUNTIONS OF A MAINTENANCE DEPARTMENT

1. Maintenance of installed equipment and facilities

2. Installations of new equipment and facilities

3. PM tasks – Inspection and lubrication of existing equipment

4. CM tasks – monitoring of faults and failures using appropriate techniques

5. Modifications of already installed equipment and facilities

6. Management of inventory

7. Supervision of manpower

8. Keeping records

9. Advice on Procurement, Usage and Discard.


Importance of sound Maintenance System

1. Maintenance costs, are normally a major portion of the total operating costs in most plants.

Studies indicate that 30% of Maint costs are wasted through ineffective maintenance management methods

2. The dominant reason for this ineffective management is the lack of factual data that quantify the actual need for repair or maintenance of plant .

Maintenance scheduling has been and in many instances still is predicated on statistical trend data or on the actual failure of plant equipment.

3. Impact of the maintenance operation on product quality, production costs, and more importantly on bottom-line profit.

4. Technology and instrumentation are now available for effective maintenance based on condition monitoring.

5. It is now possible to reduce or eliminate unnecessary repairs, prevent catastrophic machine failures, and reduce the negative impact of the maintenance operation on the profitability of manufacturing and production plants.


ELEMENTS OF EFFECTIVE MAINTENANCE MANAGEMENT

1. Maintenance Policy

2. Control of materials

3. Preventive Maintenance

4. Condition Monitoring

5. Work Order

6. Job planning

7. Priority and backlog control

8. Data recording system

9. Performance measurement measures or indices


GoAir is currently operating at 21 cities with 156 daily flights and approximately 1092 weekly flights11 aircrafts

Ahmedabad, Bagdogra, Bengaluru, Chandigarh, Cochin, Delhi, Goa, Guwahati, Jaipur, Jammu, Kolkata, Leh, Lucknow, Mumbai, Nagpur, Nanded, Patna, Port Blair, Pune, Ranchi and Srinagar.


GoAir is currently operating at 21 cities with 156 daily flights and approximately 1092 weekly flights

11 Aircrafts

Ahmedabad, Bagdogra, Bengaluru, Chandigarh, Cochin, Delhi, Goa, Guwahati, Jaipur, Jammu, Kolkata, Leh, Lucknow, Mumbai, Nagpur, Nanded, Patna, Port Blair, Pune, Ranchi and Srinagar.


Maintenance is the management of failures and the assurance of reliability


Equipment Life Cycle

Needs and Requireme

nts

Design

Production

UseRetireme

nt

Conceptual DesignPreliminary DesignDetailed Design

OperationMaintenanceSupport

ManufactureAssembly

Framework of System Design


DESIGN OF THE

PRODUCT

Produce ability

Requirement

Functional Requiremen

ts

Safety Requiremen

t

Strength Requiremen

t

Reliability Requiremen

tOperability Requiremen

t

Maintainability

Requirement

Environmental

Requirements

Cost Time

Apr 19, 2023Product Design and Development21

Product Life Cycle : Demand Curve

1. Stages of Product Life Cycle

1. Introduction2. Growth3. Maturity 4. Decline

2. Facility and process investment depends on life cycle.

Time

Dem

an

d o

f p

rod

uct 1 2

3

4


Most products go

through three distinct phases from

product inception to wear out.

Bath Tub Curve shows a typical life cycle curve for which the failure rate is plotted as function of time.


The Bath Tub Curve of Eqpt Failure Rate

1. Field failures do not generally occur at a uniform rate, but follow a distribution in time commonly described as a "bathtub curve."

2. The life of a device can be divided into three regions: Infant Mortality Period, where the failure rate progressively improves; Useful Life Period, where the failure rate remains constant; and Wearout Period, where failure rates begin to increase.


The Bath Tub Curve (Cont..)

1. Units that pass the Infant Mortality Period have a high probability of surviving the conditions provided by the system and its environment.

2. Failures that occur during the Useful Life Period are residual defects surviving Infant Mortality, unpredictable system or environmental conditions, or premature wear out.

3. Wearout failures are generally associated with such failure mechanisms as metal migration, hot electron effects, wirebond intermetallics, or thermal fatigue.


Life Cycle Costing

The sum total of direct, indirect, recurring, non-recurring and other related costs incurred

or estimated to be incurred in the design, development, production, operation,

maintenance and support of the equipment system over its anticipated useful lifespan.

01 principles and practices of maintenance planning

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