maint philosophy

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TRAINING CENTRE : Monday, April 18, 2011

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Page 1: Maint philosophy

TRAINING CENTRE : Monday, April 18, 2011

Page 2: Maint philosophy

Maintenance Management

Page 3: Maint philosophy

Major Causes of 100 Large Failures

%

38

26

12

107 3 4

Mech Failure

Operator Error

Unknown/Misc

Process Upset

Natural Hezard

Subotage

Design

Page 4: Maint philosophy

Equipment Malfunctions

Equipment malfunctions have a direct impact on:– Production capacity– Production costs– Product and service quality– Employee or customer safety– Customer satisfaction

Page 5: Maint philosophy

The Maintenance Challenge

Page 6: Maint philosophy

Maintenance Strategy Model

Page 7: Maint philosophy

Asset Performance Management

Page 8: Maint philosophy

Sources Of Unreliability

Page 9: Maint philosophy

Performance and Practice- The Current Position

Page 10: Maint philosophy

Reduces ReducesMaintenance Policy Frequency

SeverityEmphasize preventive maintenance X XProvide extra machines XReplace machine parts early XInvolve operators in maintenance X XOverdesign machines XDesign machines for maintainability XEnhance maint. dept.’s capability X X

Maintenance Policies that ReduceFrequency and Severity of Malfunctions

Page 11: Maint philosophy

11

Bathtub CurveH

azar

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te

Time

Infant mortality

Wear out failures of good items

Failure of weak items

Useful life Wear out period

Failure of manufacturing defective parts, substandard parts

Page 12: Maint philosophy

Overall objective of Maintenance

Increased plant availability andReduction of maintenance Cost

Page 13: Maint philosophy

3 generation of maintenance

Breakdown Preventive Predictive

Page 14: Maint philosophy

First Generation

• Fix It when it broke.

• Maintenance means Repair.

BREAK DOWN MAINTENANCE

Page 15: Maint philosophy

BREAK DOWN MAINTENANCE

Page 16: Maint philosophy

Second generation

• Higher Plant Availability • Longer Equipment Life• High Cost

PREVENTIVE MAINTENANCE

Page 17: Maint philosophy
Page 18: Maint philosophy

Reasons for a PM Program

Reduce the frequency and severity of interruptions due to malfunctions

Extend the useful life of equipment Reduce the total cost of maintenance by

substituting PM costs for repair costs Provide a safe working environment Improve product quality by keeping equipment

in proper adjustment

Page 19: Maint philosophy

Tradeoff Between Repairs and PMA

nnua

l Cos

t A

nnua

l Cos

t

Degree of Preventive MaintenanceDegree of Preventive Maintenance

Minimum TotalMinimum TotalMaintenance CostMaintenance Cost

PreventivePreventiveMaintenanceMaintenance

CostCostBreakdownBreakdownand Repairand Repair

CostCost

Total Total MaintenanceMaintenance

CostsCostsMinimumMinimumLevel ofLevel of

PreventivePreventiveMaintenanceMaintenance

Page 20: Maint philosophy

Third generation

Higher Plant Availability & Reliability Greater SafetyBetter product quality Longer Equipment lifeGreater cost effectivenessMaintenance means Care

PREDICTIVE MAINTENANCE

Page 21: Maint philosophy
Page 22: Maint philosophy
Page 23: Maint philosophy

Evolution of Maintenance Strategy

BREAK DOWN PREVENTIVE PREDICTIVERepair or break down Calendar / schedule On condition of machine No warning Planned Early indication of faultLost production Minimizes break down Failure predication

Machine damage Part may be replaced unnecessarily

Maximum production

High cost High cost Reduced maintenance Cost

Page 24: Maint philosophy

OPPORTUNITY MAINTENANCE

In opportunity maintenance, timing of maintenance is determined by the procedure adopted for some other item in the same unit or plant .

Page 25: Maint philosophy

DESIGN-OUT MAINTENANCE

In design out maintenance, the aim is to minimize the effect of failures and in fact eliminates the cause of maintenance. The equipment with design-out maintenance are so designed that they perform their useful economic life without any maintenance need. This is also called “Run to Destruction”.

Page 26: Maint philosophy

SOME OTHER MAINTENANCE PHILOSOPHIES

PROACTIVE MAINTENANCE:- Identify as to What can go wrong. i.e monitor the parameters that can cause failure.

RCM [Reliability Centered maintenance)- the type of maintenance is chosen with reliability of the system in consideration, i.e. system functions, failures relating to those functions and effects of the dominant functional system failures. This strategy in the beginning was applied to critical systems such as aircrafts, nuclear and space applications. At present, this is being extended to critical systems in the plant.

TPM:- Total Productive Maintenance :-TPM, a Japanese concept, involves total participation of all concerned. The aim is to have overall effectiveness of the equipment with participation of all concerned using productive maintenance system.

Page 27: Maint philosophy

Following are the major functions of a maintenance department Maintenance of installed equipment and facilities Installations of new equipment and facilities PM tasks – Inspection and lubrication of existing equipment CM tasks – monitoring of faults and failures using appropriate

techniques Modifications of already installed equipment and facilities Management of inventory Supervision of manpower Keeping records

Page 28: Maint philosophy

An effective maintenance system includes the following elements

Maintenance Policy Control of materials Preventive Maintenance Condition Monitoring Work Order Job planning Priority and backlog control Data recording system Performance measurement measures or indices

Page 29: Maint philosophy

Core Philosophy

Measurable Targets:-What gets measured get done

Focus on vital few :- Follow 80:20 rule Precision Maintenance Continual Improvement :- Small but

sustainable improvement Documentation :- Do what you write and write

what you do

Page 30: Maint philosophy

How to approach

Empower people through maximizing usage of system

Revisit processes in line with latest technology development

Extensive use of statistical tools Maximize use of machine language

Page 31: Maint philosophy

ERP System

Define & Monitor PM back-log i.e. No of man days

Develop equipment tree & develop standard code for spares

Implement fault code & follow discipline at all level

Perform RCA & monitor effectiveness Measure crew efficiency

Page 32: Maint philosophy

Material (Spares)

Monitor inventory / turn over ratio against bench mark figures

Develop extensive storage and handling system Check for non moving / obsolescence Monitor availability Extra care for Insurance spares e.g. Periodic

checking ensure smooth movement of moving part

Page 33: Maint philosophy

Documentation

Follow standard document format Document shall be specific & clear to third party Use more pictures for illustration SOP & SMP shall be treated as living document

and shall be reviewed periodically (once a year) Implement document control system

Page 34: Maint philosophy

PM Database Requirements

Detailed records, or an ongoing history, must be maintained on each machine

– Dates and frequency of breakdowns– Descriptions of malfunctions– Costs of repairs

Machine specifications/checklists for PM inspection Computers generally used to maintain a database Also, data can be kept in plastic pocket on a

machine

Page 35: Maint philosophy

Modern Approaches to PM

PM at the source - workers have the fundamental responsibility for preventing machine breakdowns by conducting PM on their own machines

Workers listen for indications of potential equipment malfunction

Maintenance-related records maintained by workers

Use of quality circles

Page 36: Maint philosophy

Precision Maintenance

Contamination Control Alignment Lubrication Control Vibration Analysis Workmanship & skill development (Introduce

Certification System)

Page 37: Maint philosophy

Reliability Maintenance

Monitor OEE Monitor MTBF Measure MTTR Focus on RCA & its effectiveness

Page 38: Maint philosophy

OEE Monitoring

Page 39: Maint philosophy

Examining The Losses- OEE

Page 40: Maint philosophy

Energy Efficiency

Large conveyor belt offers a good opportunity– Set current limit for each motor for corrective action

Check possibility of introducing VFD in large fan where flow is controlled using damper

VFD for large pump Maximum demand control (observed PLF < 0.7) Plan production to take advantage of day & night tariff

Page 41: Maint philosophy

Maintenance Excellence Model

Page 42: Maint philosophy

Maintenance KPI’s

Page 43: Maint philosophy

TRAINING

Knowledge –Skill Gap Analysis Developing Training Modules Competency Test.

Page 44: Maint philosophy

Repair Programs

Objectives– Get equipment back into operation as quickly as

possible.– Control cost of repairs crews.– Control cost of the operation of repair shops.– Control the investment in replacement spare parts.– Control the investment in standby or backup

machines.– Perform the appropriate amount of repairs at each

malfunction.

Page 45: Maint philosophy

How Speedy Should Repairs Be?CostCost

Speed of Making RepairsSpeed of Making Repairs00

MinimumMinimumTotal CostTotal Costof Repairsof Repairs

Cost of RepairCost of RepairCrews & Shops,Crews & Shops,Spare Parts, andSpare Parts, and

Standby MachinesStandby MachinesCost ofCost of

Interruptions toInterruptions toProductionProduction

Total CostsTotal Costsof Repairsof Repairs

SlowSlow FastFast

Cost of repair as a function of MTTR

Page 46: Maint philosophy

Breakdowns TriggerRepairs and Corrective Actions

An equipment breakdown should trigger two actions: Fast repair of the malfunction equipment Development of a program to eliminate cause of the

malfunction and need for such repairs in the future– Modification/redesign of malfunctioning machine– Modification/redesign of part or product being processed– Training of operators to improve machine care– More frequent preventive maintenance/inspection

Page 47: Maint philosophy

Advantages of Letting WorkersRepair Their Own Machines

Greater variety may make job more satisfying May be more sensitive to potential

malfunctions Increase flexibility Can make minor repairs faster Can avoid minor repairs by cleaning,

lubricating, adjusting and servicing machines Operate machines more carefully

Page 48: Maint philosophy

RELIABILITY CENTERED MAINTENANCE

Page 49: Maint philosophy

49

Evolution of Asset Mangement Strategy

ReliabilityAvailability

MTBFProduction

Safety

Maintenance Costdowntime

No. of failures MTTR

Break-down Maintenance

Preventive Maintenance

Predictive Maintenance

Total Productive Maintenance(TPM)

Reliability Centered Maintenance(RCM)

Page 50: Maint philosophy

Introduction to Reliability

Definition:

The probability that an item will perform a required function without failure under stated conditions for a stated period of time.

Why Reliability: When you can measure what you are speaking about and express it in

numbers, you know something about it; but when you cannot measure it, when you cannot express it with numbers, your knowledge is of a meager and unsatisfactory kind. -- Lord Kelvin, 1883, May 3

A study, in the 80’s, showed that when a customer is satisfied with a product he might tell 8 other people, whereas, a dissatisfied customer will tell 22 people.

Page 51: Maint philosophy

Various Terms Used in Reliability

MTTR (Mean Time To Repair)

MTBF (Mean Time Between Failure)

Availability

Hazard Rate =

Repair Rate =

221 RRMTTR

3321 TTTMTBF

MTTRMTBF

MTBFtyAvailabili

MTBF1

MTTR1

T1 R1 T2 R2 T3

[No of Failures per Unit time]

[ No of repairs per unit time ]

Page 52: Maint philosophy

52

Capability: Item’s ability to satisfy functional needs.

Efficiency: Item’s ability to effectively utilized the energy supplied

Quality: Item’s Fitness to a particular purpose

Reliability: The item’s ability to start or continue to operate.

Maintainability: The item’s ability to quickly start following its failure.

Understanding Few Related Key Concepts

Page 53: Maint philosophy

53

System Reliability

The main objective of system reliability is the construction of a model (life distribution) that represents the times-to-failure of the entire system based on the life distributions of the components

R1 R2

R

Series System

R2

R1 R

Parallel System- Standby2121 RRRRR 21 RRR

System failure = Failure of any component

At least one of the units must succeed for the system to succeed

Page 54: Maint philosophy

REPAIR OR REPLACE ?

Page 55: Maint philosophy

REPAIR OR REPLACE

The question as “How long to Repair “ an equipment and “When” to “REPLACE” it has quizzed the maintenance personnel since ever.

Given below are a few guidelines .

Page 56: Maint philosophy

REPAIR OR REPLACE

In modern day business environment where the impetus is placed on reduction of manufacturing cost and improving overall plant efficiency and reliability , thus directly affecting the profitability and customer’s satisfaction.

Page 57: Maint philosophy

REPAIR OR REPLACE

To know when an equipment is reaching its useful life cycle, the key is not its age but its condition. Plant equipments may be old but most of equipments are continually upgraded and maintained in order to keep up with evolving manufacturing and production requirements. However a few considerations applicable are as follows.

Page 58: Maint philosophy

SAFETY

If the equipment presents an un-acceptable safety risk to Plant , Plant Personnel, and Environment –Replace it.

In worst case scenario there could be loss of life or an environmental accident , causing huge financial loss , loss of Customer and public Confidence.

However before replacing , give consideration of possibility of Upgrading the equipment to achieve acceptable safety standard.

Page 59: Maint philosophy

EXTERNALLY IMPOSED FORCES

GOVERNMENT LEGISLATIONS:- Externally imposed changes such as those required by Govt. Legislations (Stack Emission, Noise Pollution , Waste Disposal etc) are sometimes the major reason for replacement of equipments /processes.

Example :- Open Hearth Furnaces for Steel Making. MARKET FORCES:- If the present equipment is not able to

produce to the quality standards required by the market , there is no point in producing the goods which can’t be marketed. In such condition replacement of equipment becomes imperative to meet the market demand.

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Page 60: Maint philosophy

MAINTENANCE COST

Maintenance cost associated with maintaining the equipment to acceptable reliability level may be far too expensive.

Availability of spare parts could become un-acceptable from business stand-point.

Page 61: Maint philosophy

TECHNOLOGICAL OBSCELENCE

As each organisation looks for ways and means to reduce cost ,and if the present equipment can not meet production requirement in Quantity and Quality , then it needs to be replaced. However before new equipment is bought , detailed study of life-cycle cost and reliability to be done and strategy developed.

Page 62: Maint philosophy