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A Presentation on
Measurement of
Dimension
Prepared by:
Himanshu D. Lashkari
M.E. (Elect. Eng)
S.S. Engg. College, Bhavnagar
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What is Measurement ???
Comparision of given unknown Quantitywith one of its predetermined Values
Egyptians had discovered the art of
measurementIt is only with the Greeks that the
science of measurement begins to
appear All measurements consist of three
parts: magnitude, dimensions (units)
and uncertainty
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What is Measurement
Measuring is as old as Civilization
Measuring is Interaction between
Humanity and Physical World
Measurement aid n the Economics by
improving quality of Product
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Measurement Quantities & Units
Measurements are most commonly madein the SI system
Physical quantity Common Metric System
units
Common English System
units
length meter (m), kilometer (km) inch (in), foot (ft), yard
time second second
mass kilogram (kg), gram (g) slug, pound (lbm)
temperature Degrees Celsius (oC) or
Kelvin (oK)
degrees Farenheit (oF) or
Rankin (oR)
current Ampere (A) Ampere (A)
amount of a substance mole mole
lunimous intensity candela candela
force Newton pound (lbf)
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Dimension Measurement
In Industrial applications, Measurementand control of Dimension of a product is
one of the Important quality Requirement
Dimension can be categorized into:
Thickness
Length Width
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Measurementof
Dimensions
ThicknessMeasurement LengthMeasurement WidthMeasurement
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Thickness Measurement
Contact TypeThickness
Measurement
Inductive
Type
CapacitiveType
Ultrasonic
Vibration
Type
Non ContactType
Thickness
Measurement
Capacitanc
eType
Radiation
Type
LaserBase
d
Measurement ofCoating Thickness
Differ
entialBeta-Transmissi
onGaug
e
Beta-backscatterGaug
e
X-
Rayfluorescenc
eGaug
e
Prefe
rential
absorptionGaug
e
I d i T Thi k
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Inductive Type Thickness
Measurement
There are two types of
Thickness Transducers:
Reluctance TypeThickness Gauge
Magnetic Materials
Eddy Current Type
Thickness Gauge
Magnetic and Non
Magnetic, Non
Conducting Coatings
like Paint
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Capacitive Thickness Measurement
Operating Principle isbased upon
Capacitance between
parallel plate
Mostly used for
Insulator materials
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Ultrasonic Vibration method of
Thickness Measurement
This method is based onthe time taken by theultrasound wave to return tothe surface
Lm= Ct/2 ;
Lm = Thickness of Sample,
C = Celerity of Sound in GivenSample,
t= Traverse Time
Methods of UltrasonicThickness Measurement
Pulse echo (transit time)
Resonance (Pizoelectric) Method.
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Ultrasonic Thickness Measurement
Pulse Echo (Transit) Resonance (Pizoelectric)
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Capacitance Type Non Contact
Thickness Measurement
Capacitance Variesdirectly in relation with
Thickness of
Dielectric materials
between two parallelcapacitor Plates
Used for Insulatingfilms
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Beta Radiation Gauge
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Measurement of Coating Thickness
Differential BetaTransmission Gauge
Beta Backscatter
Gauge
X- ray Fluorescence
Gauge
PreferentialAbsorption Gauge
B G
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Beta Gauges
A beta gauge consists of two basiccomponents - a source of radiation,
and a radiation detector
Beta particles are fast moving
electrons, emitted from certain
radioactive isotopes
When they strike material, some of
them will pass through, while others
will be stopped. The thicker the
material, the greater the chance aparticle will be stopped. By
measuring the ratio of the number of
particles that pass through the
material to the number without any
material, the thickness (or weight) of
the material can be determined
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Laser Based Length Measurement
Laser DopplerPrinciple is used
Light beam in contact
with moving object
will experience a shift
in its frequency
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Camera based Width Measurement
Works onStereoscope
vision principle
3 Dimensional
Images are
prepared on
this Principle
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Camera based Width Measurement
Applications Cold Strip Mills
Temper Mills
Rewinders
Slab sortingoperations
Plate finishing
areas
Side trimmers
Process lines
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