Measurement of Dimension

7/29/2019 Measurement of Dimension

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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


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


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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Measurement of Dimension

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