WEEK 9 – QUALITY AND INSPECTION

Q.1 Discuss Latest Technologies used in Inspection and Quality control?

Innovative /Latest Technologies used in Inspection

Inspection: Machine vision gives machines, robots and autonomous devices the ability to see,
detect and analyze images automatically, which can provide automated product quality
inspection from the manufacturing floor, to warehouse. Modern machine vision systems leverage
three technologies to perform better, faster and more cost-effective quality inspections.

1. Smart Cameras: Industrial, AI smart cameras, like our multi-award winning NEON Smart
Camera, integrate AI capabilities directly within the camera itself by combining hardware
with a pre-installed software environment.
2. Artificial Intelligence (AI): AI adds a new dimension to quality inspections. AI-
powered machine vision systems not only find defects or confirm proper packaging and
labeling, but they can also make decisions based on context.
3. Edge Computing: Edge intelligence enables systems to process a large volume of data
without having to send it to the cloud, reducing latency and increasing efficiency.

The integration of new technologies must be done in order to increase the safety of the
inspectors, reduce costs to the company, and improve the working conditions of the
inspectors.

Other New technologies for visual inspections are

 Tablets
 Drones
 Robots
 Augmented reality
 Virtual reality

Innovative /Latest Technologies used in Quality control

Five innovative technologies that can help you to enhance optical quality control in production
environment are:

1. IIoT radar-based optical sensors:

Precise measurements are essential for producing high quality products. Optical sensors are
generally a good option for automating such tasks.
2. Membrane-free acoustic sensors:
While optical sensors convert light into electrical signals, acoustic sensors are acoustoelectric
transducers, i.e., they convert acoustic signals into electrical signals. Unlike optical sensors,
acoustic sensors are not affected by object color, transparency or material, nor are they sensitive
to dust, smoke or light. By sending out high-frequency sound waves beyond the range of human
hearing, ultrasonic sensors can accurately measure distances and detect defects for the purpose of
quality control. Usually, acoustic sensors require membranes or other moving parts to do this.
3. Deep learning-based visual inspection software:
Currently, quality inspection is primarily performed by human experts, which is both costly and
insufficiently reliable, despite decades of accumulated experience. Lead to Deep Learning-based
technology solutions. Deep Learning is a subset of machine learning in AI, in which artificial
neural networks develop said experience in a dramatically condensed time frame. This offers
exponential learning capabilities that can be put to great use.
4. 3D scanner with HD accuracy:
Having an accurate 3D inspection process is another crucial step towards optimal quality control.
It allows users to reliably measure sub-millimeter features and frees up employees from spending
unproductive hours doing something the right device does quicker and better.
5. AR-based model tracking:
Augmented Reality is another key enabling technology of Industry 4.0 and has the potential to
revolutionize quality control.
AR enables the checking of desired and actual construction states for inconsistencies, missing or
wrongly installed parts while they are still in the prototyping phase.

Q.2 Perform measurement with desired accuracy to check the components for Functionality and
conformance to defined standards using Vernier caliper?

Fig : Vernier caliper

 The vernier scale was invented in its modern form in 1631 by the French mathematician
Pierre Vernier (1580–1637). Vernier instruments are being used for more than two
centuries. The American, Joseph Brown, is credited with the invention of the vernier
calliper.
 Vernier instruments based on the vernier scale principle can measure up to a much finer
degree of accuracy.
 The American, Joseph Brown, is credited with the invention of the vernier calliper.
 A vernier scale provides a least count of up to 0.01mm or less, which remarkably
improves the measurement accuracy of an instrument.
 A vernier scale comprises two scales: the main scale and the vernier scale.
 Let us say that the main scale has graduations in millimetres up to a minimum division of
1mm. The vernier scale also has graduations, having 10 equal divisions. In this example,
10 vernier scale divisions (VSDs) equal nine main scale divisions (MSDs).
 Calculation of least count :
The minimum length or thickness that can be measured with a vernier scale is called the
least count. For a forward vernier shown in Fig. 4.23, N VSD = (N−1) MSD 1 VSD =
(N−1)/N MSD Least count = 1 MSD − 1 VSD
Therefore, Least count = 1 MSD − (N − 1)/N MSD
Least count = [1− (N − 1)/N] MSD
Least count = 1 MSD/N
 Total reading = MSR + (VC × LC), where MSR is the main scale reading, LC is the least
count, and VC is the vernier coinciding division.

Fig : Vernier caliper Fig : Vernier caliper

 From above fig where the fourth division of the vernier coincides with a division on the
main scale.
 Least count = 1 MSD/N = 1mm/10 = 0.1mm
Therefore, total reading = 1 + (4 × 0.1) = 1.4mm
VERNIER CALLIPERS

Aim: To find the volume of sphere by using a vernier callipers.

Apparatus: Vernier caliper, rectangular block and magnifying glass.

Theory: Volume of the sphere,V=(4/3)Пr3 (in m3 ) Where r=radius of the sphere (in m)

Least count: It is the smallest measurement that which any measuring instrument can measure
accurately(value of one division=L.C.)

Observations and calculations: Least count =Value of one main scale division/Total no: of
vernier scale divisions

L.C.=1div/10=1mm/10= 0.1mm )

To find the diameter of the sphere

Sl.No Dimension MSR VSR (VSR x LC) D=MSR+(VSR x

(mm) (Div) LC) mm
1
2
3 d=Diameter
4
5
Mean diameter
d=……..mm

Radius of the sphere, r=d/2 = mm

Volume of the sphere, V= (4/3) Пr3 =------------------mm3

Procedure:

1. Calculate the LC of vernier calipers.

2. Measure length, breadth & thickness of a rectangular block and diameter of the given sphere
by using vernier calipers.

3. Find MSR and VSR for each physical quantity.

4. Calculate the total reading by using the formula MSR+(VSR x LC) .

5. Find the volume of block using the equation V=lbh & volume of the sphere V= (4/3) Пr3

6. Repeat the experiment 4 or 5 times.

Precautions:

1. The movement of vernier scale on main scale should be smooth

2. Take measurements of diameter by changing the orientation of the body

3. Notice the readings carefully to avoid error due to parallax

Sources of error

1. In poor quality of vernier calipers jaws may not be perpendicular to scales

2. Parallax may be there in taking the observations

Result: Volume of the sphere, v = ------------- mm3

Q.3 Perform measurement with desired accuracy to check the components for Functionality and
conformance to defined standards using Micrometer?

 The word micrometer is believed to have originated in Greece, the Greek meaning for
this word being small.
 The word ‘micrometer’ is known by two different meanings. The first is as a unit of
measure, being one thousandth of a millimeter. The second meaning is a hand-held
measuring instrument using a screw-based mechanism.
 The first ever micrometer screw was invented by William Gascoigne of Yorkshire,
England, in the 17th century and was used in telescopes to measure angular distances
between stars. The commercial version of the micrometer was released by the Browne &
Sharpe Company in the year 1867.

Fig : Illustration of the relevance of Abbe’s law for micrometers and Vernier
callipers.
  A micrometer can provide better least counts and accuracy than a vernier caliper. Better
accuracy results because of the fact that the line of measurement is in line with the axis of
the instrument, this fact is best explained by Abbe’s principle, which states that
‘maximum accuracy may be obtained only when the standard is in line with the axis of
the part being measured.
 Calculation of least count :
Least count: It is the smallest measurement that which any measuring instrument can
measure accurately (value of one division=L.C.)
Zero error=-------------------div
Pitch of the screw =distance moved/no: of rotations made
=4mm/4
=1mm
Least count(LC) =Pitch of the screw/Total no of circular scale divisions
=1mm/100
=0.01mm

Fig : Illustration of the micrometer scale is reading when a job is held between the anvil face and the spindle face

callipers.

 Above Figure illustrates how the micrometer scale is read when a job is held between the
anvil face and the spindle face
 In this example, the main scale reading is 8.5mm, which is the division immediately
preceding the position of the thimble on the main scale. As already pointed out, let us
assume the least count of the instrument to be 0.01mm. The 22nd division on the thimble
is coinciding with the reference line of the main scale. Therefore, the reading is as
follows: 8.5 + 22 (0.01)mm = 8.72mm
 ADVANTAGES OF MICROMETER:
 More accurate than rules.
 Greater precision than calipers.
 No parallax error
 Relatively in expensive end measurement

DISADVANTAGES OF MICROMETER:
 Short measuring range
 End measurement only
 Single purpose instrument.
 Limited wear area of anvil and spindle tip.

APPLCATIONS:
 It can be used to measure diameter of a wire, thickness of a thin metal sheet, etc
 These instruments are used to check round work pieces accurately.
 It is also used to check wall thickness of the pipe.
Aim: To find the thickness of the given wire and sphere using a micro meter and hence to find
their volumes.

Apparatus: Screw gauge, thin wire, small sphere and meter scale.

Theory:

(a) Volume of the given wire= πr2 h in mm3 Where r=radius of the wire (in mm) h=length of the
wire. (in mm)

Observations and calculations

Least count: It is the smallest measurement that which any measuring instrument can measure
accurately (value of one division=L.C.) Zero error=-------------------div

Pitch of the screw =distance moved/no: of rotations made

=4mm/4

=1mm

Least count(LC) =Pitch of the screw/Total no of circular scale divisions

=1mm/100

=0.01mm

Length of the given wire, h= ----------- cm = --------- mm (1)

To find the diameter (thickness) of the given wire

Sl No PSR(mm) HSR(Div) CHSR(Div) CHSRxLC Diameter, d=PSR+

mm (CHSRx LC) (mm)
1
2
3
4
5

Radius of the wire, r=d/2= -------- mm

Volume of the wire, V= πr2 h =---------- = ----------------- mm3

Procedure:

1. Measure the Zero correction and least count of screw gauge.

2. Measure the diameter of the given wire and sphere using screw gauge.

3. Find PSR,HSR and CHSR using screw gauge.

4. Calculate PSR+(CHSRxLC).

5. Measure the length of the given wire by using metre scale.

6. Find volume of wire and sphere using the formulae V= πr2 h& V=(4/3) πr3

7. Repeat the experiment 4 or 5 times.

Precautions

1. At a time rotate the screw in one direction to avoid backlash error

2. Zero error should be observed carefully and taken into consideration

Sources of error

1. The wire may not be of uniform cross section

2. Backlash error always exists because it cannot be removed completely

Result: Diameter of the given wire, d= -------- mm

Volume of the wire, V = ---------- mm 3

Q.4 Perform measurement with desired accuracy to check the components for Functionality and
conformance to defined standards using Vernier height gauge, Vernier depth gauge Bevel
Protractor, Sine bar, and Dial Indicator?

VERNIER HEIGHT GAUGE

Fig : Vernier Height Gauge

Aim: To measure the height of the object using vernier height gauge

Theory:
 In a vernier height gauge, the graduated scale or bar is held in a vertical position by a
finely ground and lapped base.
 The job to be measured is held between the base and the measuring jaw.
 The measuring jaw is mounted on a slider that moves up and down, but can be held in
place by tightening of a nut.
 A fine adjustment clamp is provided to ensure very fine movement of the slide in order to
make a delicate contact with the job.
 In depth gauge, the main scale in a height gauge is stationary while the slider moves up
and down.
 The vernier scale mounted on the slider gives readings up to an accuracy of 0.01mm.
 Vernier height gauges find applications in tool rooms and inspection departments.

Procedure:
 Place the object and the vernier height gauge on the surface plate.
 Note the value on the scale when the moving jaw is touching the bottom of the object.
 Take the moving /sliding jaw to the top of the object and note down the value on the
scale.
 The difference between 3&2 will give the height of the object.
 Least count = ------------ mm.
Sl.No Measured Reading when Measured Reading when moving Height of the Object=
moving jaw touches bottom of jaw to the top of object. = Column3- column2
object. = (MSR+VSRxLC ).mm (MSR+VSRxLC ).mm

Precautions to be taken:

 One should avoid exerting force while pushing the slider against the surface of the job
being measured.
 Periodic cleaning and lubrication are mandatory, as the main scale and fine adjustment
mechanism are always in motion in the process of taking measurements.

Result: The Height of the Object= …….mm

 VERNIER DEPTH GAUGE

Fig : Vernier Depth Gauge

Aim: . To measure the depth of the object using Depth gauge.

Theory:
 A vernier depth gauge is a more versatile instrument, which can measure up to 0.01mm
or even finer accuracy.
 Above Fig. illustrates the constructional features of a vernier depth gauge.
 The lower surface of the base has to butt firmly against the upper surface of the hole or
recess whose depth is to be measured. whereas the main scale can slide up and down.
 The main scale is lowered into the hole or recess, which is being measured.
 Vernier depth gauges can have an accuracy of up to 0.01mm.

Procedure
 .Held the base on the reference surface.
 Lower the beam into the hole until it contacts the bottom surface of the hole.
 Make final adjustment with fine adjustment screw.
 Tighten the clamping screw and remove the instrument from the hole and take the
reading in the same way as vernier.
 Least count = ------------ mm.
 Sl. Main Scale Reading Vernier Scale Reading Measured Reading =
(MSR)…mm (VSR)…mm MSR+VSRxLC ..mm

Precautions to be taken:

 One should avoid exerting force while pushing the scale against the surface of the job
being measured, because this will not only result in the deformation of the scale resulting
in erroneous measurements, but also accelerate the wear and tear of the instrument.
 Periodic cleaning and lubrication are mandatory, as the main scale and fine adjustment
mechanism are always in motion in the process of taking measurements.

Result: The Height of the Object= …….mm

Universal Bevel Protractor

Fig : Universal Bevel protractor

Theory : callipers.
 The universal bevel protractor with a 5' accuracy is commonly found in all tool rooms
and metrology laboratories.
 . Figure illustrates the construction of a universal bevel protractor.
 It has a base plate or stock whose surface has a high degree of flatness and surface finish.
The stock is placed on the work piece whose angle is to be measured.
 An adjustable blade attached to a circular dial is made to coincide with the angular
surface. It can be swiveled to the required angle and locked into position to facilitate
accurate reading of the circular scale that is mounted on the dial.
 The main scale on the dial is divided into four quadrants, each measuring 90°. Each
division on this scale reads 1° The vernier scale has 24 divisions, which correspond to 46
divisions on the main scale.
 Calculation of Least Count:
Value of one main scale division = 1° 24 vernier divisions correspond to 46 main scale
divisions. From Fig. it is clear that one vernier division equals 1/12th of 23°. Let us
assume that the zeroth division on both the main and the vernier scales are lined up to
coincide with each other. Now, as the dial rotates, a vernier division, starting from the
fifth minute up to the 60th minute, progressively coincides with a main scale division
until the zeroth division on the vernier scale moves over the main scale by 2°. Therefore,
the least count is the difference between one vernier division and two main scale
divisions, which is 1/12° or 5'.
Fig : Divisions on Vernier scale Fig : Reading the Vernier scale

 Reading Vernier Scales

callipers. callipers.

Consider the situation shown in Fig. 5.3. The zeroth division of the vernier scale is just
past the 10° division on the main scale. The seventh division, marked as the 35' division,
on the lefthand side of the vernier scale coincides with a division on the main scale.
Therefore, the reading in this case is 10°35'.
 Divisions on the vernier scale (in minutes) Main scale (in degrees)
 Always read the vernier from zero in the same direction that you read the dial scale. In
the given example, the 10th division on the dial, which is close to the zeroth division on
the vernier, is to the left of the zero th division on the dial scale. In other words, the dial
scale is being read in the leftward or anticlockwise direction. Therefore, the vernier
should also be read towards the left of the vernier zero division.
 Fig : wedge angle measurement

AIM: To measurecallipers.
the angle of the given wedge using Bevel Protractor

Apparatus required:

1. Work piece

2. Bevel Protractor.

Theory: Universal Bevel Protractor:

A bevel protractor is a graduated circular protractor with one pivoted arm; used for
measuring or marking off angles. Sometimes Vernier scales are attached to give more
precise readings.

Construction:

Fixed Blade: Fixed blade also known as beam which is attached to the circular main
scale.

Moveable Blade: Moveable blade is inserted to the fixed blade and can be rotated at 360°.

Knob: Knob is used to tighten the moveable blade at its place.

Main Scale: Circular Scale around which moveable blade rotates.

Vernier Scale: The scale below the Main scale is known as vernier scale
 Procedure:

1. Firstly attached the surface of the job with the help of stock and blade.

2. Then see and write which line of the main scale is matching with the 0 lines of the
vernier scale.

3. Then see which line of the Vernier scale matches with the line of the main scale in the
forwarding direction.

4, And then multiply by 5 whatever readings you get.

5 After that added both reading and which value is obtained is vernier bevel
protractor reading.

Care and Maintenance of Vernier Bevel Protractor

1. Always clean the Vernier bevel protractor before use.

2. After use, it should be kept in a safe place with a thin coating of oil.
Observations and calculations

Sl.No Angle measured

1
2
3
4
5

Result:

The angle of the given specimen measured with the Bevel Protractor
SINE BAR

Fig(Left) : construction details of a sine bar Fig (Right): Application of a sine rule for angle
measurement. bar
 A sine bar is used to measure angles based on the sine principle. Its upper surface forms
the hypotenuse of a triangle formed by a steel bar terminating in a cylinder near each end.
When one of the cylinders, called a roller, is resting on a flat surface, the bar can be set at
any desired angle by simply raising the second cylinder. The required angle is obtained
when the difference in height between the two rollers is equal to the sine of the angle
multiplied by the distance between the centres of the rollers. Figure (L) illustrates the
construction details of a sine bar.
 Sine bar is used to measure or set accurate angles. It consists of a bar to which two rollers
of equal diameter are attached. The distance between the axes of rollers is fixed to a high
degree of accuracy. When the rollers are brought in contact with a flat surface, the top of
the sine bar is parallel to the flat surface.
 Sine bars are made of corrosion-resistant steel, and are hardened, ground, and stabilized.
The size is specified by the distance between the centres of the cylinders, which is 100,
200, or 300mm.
 The upper surface has a high degree of flatness of up to 0.001mm for a 100mm length
and is perfectly parallel to the axis joining the centres of the two cylinders. The
parallelism of upper surface with the datum line is of the order of 0.001mm for a 100mm
length.
 Fig (Right) illustrates the application of a sine rule for angle measurement. The sine of
angle q formed between the upper surface of a sine bar and the surface plate (datum) is
given by
Sin θ = h/L
Where h is the height difference between the two rollers and L is the distance between the
centres of the rollers.
Therefore, h = L Sin θ
 Fig : Dead center taper angle measurement by sine bar

Aim: To measure the taper angle of dead centre using side bar

Apparatus required:

1. Dead centre

2. Sine Bar

3. Set of Slip gauge

4. Surface Plate

5. Angle Plate

6. Magnetic stand

Procedure:

1. Clean the protective grease from the slip gauge, the sine bar with a clean cloth or
acetone or carbon tetrachloride or other suitable solvent. Wipe the surface plate with a
clean, dry soft cloth.

2. Place the dead centre with one of its generators resting on the surface Plate as shown
in the figure

3. Rest the sine bar on the top surface of the dead centre ensuring a line contact
throughout.

4. Adjust the position of the sine bar such that the rollers are free to take supports.
 5. Bridge the gap between rollers and the surface plate with a pile of slip gauges S1 and
S2, such that the roller make a positive line contact over the slip gauge surfaces.

6. Then by several trails obtain slip gauge heights S1 and S2 so as to have the height in
three decimals.

7. Taper angle of the dead centre is calculated and cross checked using optical bevel
protractor.

Observation:

Length of Sine bar, L = _ _ _ _ _ mm

Height of Slip gauge, S1 = _ _ _ _ _ mm

Height of Slip gauge, S2 = _ _ _ _ _mm

Then sin 𝜃 = (𝑆2−𝑆1)/ 𝐿

θ = sin−1 (𝑆2 − 𝑆1)/ 𝐿

Then Taper angle = 𝜃/ 2 = _ _ _ _

Result:

1. Taper angle of dead centre using sine bar is _ _ _

BORE DIAL GUAGE
Theory:
It is used for measuring internal diameter of a hole, which is machined. The bore dial gauge
consists of one fixed measuring head and one movable measuring head. The movement of the
movable measuring rod is transmitted to dial indicator by push rod through a spring actuated
hinged member. Thus the horizontal movement of the rod is transmitted into vertical direction
gives indication of variatopn of size. The calibrated rods are made in different sizes and
sometimes number of short rods threaded at the ends are used in combination to get different
desired lengths

Procedure:
 The measuring head is placed in contact with the surface of hole.
 The movement of measuring head contact point is transmitted to the amplifying
mechanism by the calibrated rods and its shown on the dial indicator.
 These calibrated rods are located in tabular supports between the head and dial units. The
readings from dial indicator are tabulated as below.

Sl.No Diameter Trial 1 Trial 2 Average Measured Diameter

Note: Please avoid dropping the tools as this can lead to irreparable damage to the precision
instruments. The tools are coated with a light film of oil to prevent corrosion. Please do not
remove this oil. A cloth has been provided to clean your hands after use.
RESULT:
The specifications of the given component are measured with bore dial gauge.
Q.4 Demonstrate the construction and working Principle of Profile Projector Check the Dimensional
Accuracies of the Models using Profile Projector?

PROFILE PROJECTOR

Aim: To Measure the thread parameters using profile projector.

Apparatus required:

1. Profile projector

2. Screw thread (Metric)

3. Pitch gauge (Metric)

4. Micrometer
Construction And Working :
 Profile projector is a precision measuring device that provides fast, simple and reliable
quality control. Profile projector projects the profiles at desired magnification.
 Profile projector consists of a lens system, measuring system and a screen.
 The lens system consists of a light source, magnification lens system, a focus control
threaded tube for profile and surface illumination.
 The measuring system consists of an X- Y table each with a micrometer and a protractor
scale on the screen.
 The projection screen is made of thick ground glass to give uniform distribution of light.
There is a radial graduated vernier scale for angular measurement. It also has cross wires
for reference during linear measurement.
 The drawing of the profile drawn to same magnification as the projected image can also
be fixed on the screen and compared.
 The application of profile projectors are tracing of profiles on tracing paper, to measure
terminology of screw threads, gears , control of squareness and parallelism etc.

Observation:

1. Pitch of the thread measured using pitch gauge, P = _ _ _ _ mm

2. Major diameter of the thread measured using micrometer D1 = _ _ _ _ mm

Procedure:

1. Place the specimen on the table and clamp it.

2. Adjust the magnification lens for required magnification.
3. The magnified image of thread is seen on the screen.
4. Adjust the Y-axis to the lower position of threads.
5. Reset the reading display.
6. Make the axis to the opposite ends of the threads and note down the readings which gives
outside diameter of thread
7. Similarly pitch is measured by operating on X-axis.
8. Angle of the thread can be found by adjusting the scale line to the flanks of the threads by
swiveling the screen and reading angle directly.
Result:
1. The pitch of screw thread, P = _ _ _ _ mm
2. Major diameter of screw thread, D1 = _ _ _ _ mm
3. Minor diameter of screw thread, D2 = _ _ _ _ mm
4. Angle of thread, θ = _ _ _ _ degrees