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.
CONDITION BASED MAINTAINACE BASICS presentation
RAJKUMAR S WAGMARE
1st sem M.Tech MSE
M.S.RAMAIAH INSTITUTE OF TECHNOLOGY
(AUTONOMOUS INSTITUTE,AFFILIATED TO VTU)
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
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,
2. Product Quality
3. Overall effectiveness of manufacturing
4. Availability of process machinery.
CBM Optimize total plant operation
It is a comprehensive predictive maintenance management
Reduce greatly cost of maintenance
Lower maintenance cost
Fewer repairs down time
Reduced small parts inventory
Longer machine life
Improved operator safety
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
Oil analysis and Tribology
Motor current analysis
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 CBM
Two main methods used for condition monitoring
This is the continuous or regular measurement and interpretation of data,
collected during machine operation, to indicate safe and economical
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
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
o The decay in early life and the increase in final life can be considered to be
V= E exp (-t/e) + M + F ((t/T)/f)
E & e control the various decay in early life
M is vibration in mid life
F & 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.
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.
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.
3. Temperature Monitoring
The Temperature Monitoring sensitive aspects of a unit can
be readily monitored.
These include contact Thermometers, Thermocouple,
Thermistor, Temperature chalks and paints and infrared
The 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
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.
Studies have estimated that a properly functioning of CBM or predictive
maintenance program can provide a savings of 8% to 12% over
maintenance 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
Wind turbine generators
Marine diesel engines
Natural gas compression
Circuit card manufacturing
Disadvantages of CBM
Diagnostic equipment being costly has increased the
Staff training increased the investment
Management cannot see readily potential savings
Now floor is open for…