The document discusses various methods of non-destructive testing (NDT) used to inspect equipment and products for defects or deterioration without dismantling them. It describes common NDT techniques like visual inspection, liquid penetrate testing, magnetic particle testing, ultrasound testing, vibration analysis, infrared imaging, and X-ray testing. The techniques analyze factors like surface cracks, corrosion, material density variations, and component temperatures to predict failures and maintenance needs. NDT allows for safe inspection and condition monitoring to improve equipment reliability.

1. MODULE 2
NON-DESTRUCTIVE TESTING
Three R's of maintenance
1. Routine
2. Renewal
3. Repair
Maintenance
Renewal Routine Repair
Inspection Adjustment Lubrication
Inspection means of predicting a need for future work for example (visual
or condition monitoring equipment to check all wearing parts)
Equipment wear records: in the predictive maintenance program the above
methods utilizes to predict failures. The wear of the equipment plotted against
time. As the wear progressing a graph is made. This prevents a breakdown and
allows the maintenance staff the flexibility to schedule the repair without
interrupting production.

2. Non-destructive testing
To know the amount of deterioration in a piece of equipment or the condition of
finished product without destroying or dismantling the product.
Types of Non-destructive testing
1. Liquid penetrate
2. Magnetic particles
3. Ultra-sound
4. Visual inspection
5. Vibration analysis
6. X-ray
7. Thermography
Visual inspection
Basic principle:
 Illuminate the test specimen with light
 Examine the specimen with the eye
Used to:
To magnify defects which can not be detected by the unaided eye
To assist in the inspection of defects
To permit visual check of areas not accessible to unaided eye
Advantage
Most widely used of all nondestructive tests
Simple, easy to apply, quickly carried out and usually low in cost

3. Visual inspection equipment
 Magnifying glass
 Magnifying mirror
 Microscope
 Bore scope
 Flexible fiber optic bore scope
 Video image scope

4. Liquid penetrate (LP)
Principle:
The surface part under evaluation is coated with a penetrant in which a visible or
dye is dissolved the penetrant is pulled into surface defects by capillary action
After a waiting period to insure the dye has penetrated into the cracks, the
excess penetrant is cleand from the surface of the sample. A white powder called
developer is the sparyed or dusted over the part. The developer lifts the
penterant out of the defect.
Example of applications:
Detection of cracking and porosity in welded joints
Detection of surface defects in casting
Detection of fatigue cracking in stressed materials
Equipment:
Portable systems in spray

5. Magnetic particle (MP)
Principle:
The sample is magnetized are dusted over the sample. A surface defect will form
a magnetic anomaly attracting and holding magnetic particles and giving a visual
indication of the defect
Example of applications:
Fatigue cracks in steel dies
Shrinkage in machined castings
Stringers or cold shunts in forgings after finish machining
Equipment:
Fixed piece of equipment or portable system for use in the field

6. Ultra-sound (UT)
Principle:
Ultrasonic test (UT) uses high frequency sound energy to conduct examinations
and measurements.
Equipment:
Pulse/receiver produce high voltage electrical pulse
Transducer generates high frequency ultrasonic energy the sound energy
is introduced and propagates through the materials in the form of waves
Display devices
Example of applications:
Detection of cracks, voids and inclusions
Detection of density variations on the order 0.25% or less
Samples which require resolution as small as 2 microns in three
dimensions
Samples can be inspected for both surface characteristics as well as bulk
properties
Examining bolts or rivets in aircraft wings to find crakes and defects
Inspection of carbon composites for aging or impact damage
Weld penetration inspection
Weapons stockpile surveillance

7. Vibration analysis
Vibration analysis it analyzes the cause of vibration instead of just determining
the level of vibration
Vibration has two main characteristics frequency and amplitude
Frequency : is the number of times that a part oscillates through a cycle in one
second expressed in hertz or cycles per minute (CPM) is usually reserved for
equipment of a slower speed
Amplitude: is the measure of the severity of the vibration can be measured in
three ways
Displacement
Velocity
Acceleration
Displacement is the actual amount of movement that takes place it's measured
in peak-to-peak displacement is usually used to measure low or constant speed
machinery
Velocity: is the speed at which the displacement takes place is used on all
frequencies of rotating machinery
Acceleration: is the time rate of change in velocity is used on high speed
rotating equipments
Example of applications:
Unbalance
Defective bearings
Misalignment
Looseness
Oil whip
Bend shaft

8. Infrared imaging
Thermo graphic Principle:
Heat flow in a material is altered by the presence of some types of
anomalies
These changes in heat flow cause localized temperature differences
in the material
Slow heating of part reveals these anomalies
General uses:
To remotely examine surface temperatures of objects
Measuring temperature of hot pressings
Temperature measurement of material inside furnaces and material being
heated by microwaves
Observing temperature gradients across molded plastic
Measuring temperature of circuit board components during operation
Line scan mode enables measurement of a single line
Equipment:
IR imaging system

9. X-RAY
Principle:
A source of radiation is directed toward an object a sheet of radiographic film is
placed behind the object the density of the image is a function of the quantity of
radiation transmitted through the object which in turn is inversely proportional to
the atomic number density and thickness of the object
Equipment:
 X-ray sources
 Radiograph scanners
 Digital images
General uses:
 Generation of images corresponding to density atomic number and
thickness variation of static solid objects
 Check for internal defects such as voids cracks
 Determination of internal clearances between parts in an assembly