Presented by:

RAJKUMAR S WAGMARE

1MS15MSE03

1st sem M.Tech MSE

M.S.RAMAIAH INSTITUTE OF TECHNOLOGY BANGALORE

(AUTONOMOUS INSTITUTE,AFFILIATED TO VTU)

CONDITION BASED

MAINTENANCE

CONTENTS Introduction to Condition Based Maintenance (CBM)

Benefits of CBM

Principle of CBM

Methods of CBM

Advantages and Disadvantages of CBM

Applications of CBM

Condition Based Maintenance (CBM) or predictive maintenance is a technology that strives to identify incipient faults before they become critical which enables more accurate planning.

CBM is a set of maintenance actions based on real-time or near-real time assessment of equipment condition which is obtained from embedded sensors

It allows maintenance to be scheduled, or other actions to be taken to avoid the consequences of failure.

CBM is the means of improving,1. Productivity2. Product Quality3. Overall effectiveness of manufacturing4. Availability of process machinery.

INTRODUCTION

INTRODUCTION

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CBM Optimize total plant operationIt is a comprehensive predictive maintenance managementReduce greatly cost of maintenanceLower maintenance costFewer repairs down timeReduced small parts inventoryLonger machine lifeIncreased productionImproved operator safetyOverall profitability

INTRODUCTION

Condition monitoring is the process of monitoring a parameter

of condition in machinery, such that a significant change is

indicative of a developing failure.

Condition monitoring includes:

Vibration measurement and analysis

Infrared Thermography

Oil analysis and Tribology

Ultrasonics

Motor current analysis

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o Conditional Monitoring includes 3 Steps:

• Detection (when) of the developing fault at an early stage. • Diagnosis (what) of its origin so that spare parts can be ordered.• Prognosis (forecast) subsequent measurement which will then establish

the trend and enable the repair scheduled to be planned.

Detection(when) Diagnosis(what) Prognosis(forecast)

Principle of CBMTwo main methods used for condition monitoring Trend monitoring Condition checkingTrend monitoring This is the continuous or regular measurement and interpretation of data,

collected during machine operation, to indicate safe and economical operation.The principle involved is as illustrated

This follows the normal Life Curve Condition (Bath Tub Curve).

o Rapidly decreasing failure rate in early failure by lasts several weeks to few months

o Failure rate levels off long period is called stable failure period and last begins to increase material wear out and degradation failure occurs at an ever increasing rate

o The decay in early life and the increase in final life can be considered to be Exponential

V= E exp (-t/e) + M + F ((t/T)/f)E & e control the various decay in early lifeM is vibration in mid lifeF & f are growth in vibration during final life leading up to machine failure

near time T

PERFORMANCE AND BEHAVIOR MONITORING It involves checking the performance of a machine or component to see

whether it is behaving correctly. This may, for example, involve monitoring the performance of a bearing by measuring its temperature to see whether it is carrying out its function of transmitting load between moving surfaces with the minimum of friction.

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Condition Checking In which particular or instant condition while machine is running readings can be taken This is where a check measurement is taken with the machine running, using some suitable indicator and then this is used as a measure to check machine condition.

METHODS OF CONDITION MONITORING

Visual monitoring

Vibration monitoring

Temperature monitoring

Lubricant monitoring

Leak detection

Noise monitoring

Corrosion monitoring

It involves inspection and recording of surface appearance. This may involve the use of Boroscopes to see inaccessible places, the use of photography or surface imprinting for record purposes

1. Visual Monitoring

It involves the attachment of a transducer (velocity probe, accelerometer or proximity probe) to a machine to record its vibration level. Special equipment is also available for using the output from the sensor to indicate the nature of the vibration problem and even its precise cause.

2.Vibration Monitoring

3. Temperature MonitoringThe Temperature Monitoring sensitive aspects of a unit can be readily monitored.These include contact Thermometers, Thermocouple, Thermistor, Temperature chalks and paints and infrared detectors.

4.Lubricant MonitoringThe use of magnetic drain plugs in unit lubrication sumps is well known. The existence of magnetic debris gives information on the surface condition of load bearing parts

5. Leak Detection

A number of leak detecting techniques are available, including soap and water methods . the use of proprietary preparation can make this method more effective. Ultrasonic detection is one of the powerful techniques

It is usually applied to fixed plant containing aggressive materials is intended to monitor the rates of internal corrosion of the walls of the plant. This may be done by drilling sentinel holes partway through the wall, which can be plugged when they leak or by inserting readily removable coupons of material of which the corrosion rate is assumed to relate to that of the plant

6. Corrosion Monitoring

7. Wear Debris Monitoring It works on the principle that the working surfaces of a

machine are washed by their lubricating oil, and any damage to them should be detectable from particles of wear debris in the oil. If the debris consists of relatively large ferrous lumps such as those generated by the fatigue of rolling element bearings and gears or the pitting of cams and tappets, these can be picked up by removable magnetic plugs inserted in the oil return lines. For smaller debris particles, spectrographic analysis or microscopic examination oil samples after magnetic separation are commonly used techniques.

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Advantages

Studies have estimated that a properly functioning of CBM or predictivemaintenance program can provide a savings of 8% to 12% over preventivemaintenance program alone.

Independent surveys indicate the following industrial average savings :

• Reduction in maintenance costs: 25% to 30%• Elimination of breakdowns: 70% to 75%• Reduction in equipment or process downtime: 35% to 45%• Increase in production: 20% to 25%.• Increased component operational life/availability.• Allows for preemptive corrective actions.• Decrease in costs for parts and labor.• Better product quality.• Improved worker and environmental safety.

Application of Condition Based Maintenance

Used in detecting the malfunctioning

Detection of component failure

Used in assessing the formalized techniques

The CBM process can be applied to maintain activities in all industries, including: DoD weapons systems Jet engines Wind turbine generators Marine diesel engines Natural gas compression Circuit card manufacturing

Disadvantages of CBM Diagnostic equipment being costly has increased the

investment

Staff training increased the investment

Management cannot see readily potential savings

Now floor is open for…

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