Processing & Properties of Floor and Wall Tiles.pptx
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1. COURSE TITLE:
1
Course Objectives:
•Understand the advances in technology, measurement
techniques, types of instrumentation devices, innovations,
refinements.
•To learn various flow measurement techniques.
2. Course Outcome
CL
(cognitiv
e Level)
Linked PO
(Program
Outcome)
Teachin
g Hrs
CO1
Know the terms of the measurements, and Understand
the principle of operation of an instrument, Choose
Suitable measuring instruments for a particular
application and Apply ethical principles while measuring
dimensions
R/U/A 1,2,3,10 12
CO2
Appreciate Measurement of strain by using a basic
strain gauge and hence verify the stress induced and
application of transducers in mechanical engineering
applications for sustainable development
R/U/A 1,2,3,10 10
CO3
Apply the principles of instrumentation for transducers
& measurement of non electrical parameters like
temperature, pressure, flow, speed, force and stress in
mechanical engineering applications for sustainable
development
R/U/A
1,2,3,6,
10
15
CO4
Apply the principles of Miscellaneous measurements for
humidity, density, level and blood pressure.
U/A
1,2,3,4,6,
10
06
CO5
Apply the principles of limits, fits, tolerance and Analyse
the process alignment testing of machine tools for
manufacturing field.
R/U/A
1,2,3,4,6,
10
09
2
3. COURSE CONTENT AND BLUE PRINT OF MARKS FOR SEE
Unit
No Unit Name
Hour Questions to be
set for
SEE
Marks
weightag
e
weightage
(%)
R U A
1
Measuring
instruments
12
10 10 10 30 21
2
Transducers and
strain gauges
10
5 10 15 30 21
3
Measurement of force,
torque, and pressure
06
05 05 10 20 14
4
Applied mechanical
measurements
09
05 05 15 25 17
5
Miscellaneous
measurements
06
-- 5 10 15 10
6
Limits, Fits, Tolerance
& Testing of Geometric
Dimensions
09
5 10 10 25 17
Total 52 30 45 70 145 100
3
4. UNITI: MEASURING INSTRUMENTS
12Hrs
4
1) Measurement-definition-methods of measurement
2) Significance of measurement -Terms applicable to measuring
instruments Precision and Accuracy, Sensitivity and Repeatability,
3) Range, Threshold, Hysteresis, calibration
4) Errors in Measurements-Systematic and Random error.
5) Measuring instruments- Factors in selecting the measuring
instruments
6) Thread measurements:-Bench micrometer-
7) Thread gauge micrometer
8) Angle measurements- Bevel protractor, Sine Bar,
9) Gauges: plain plug gauge, snap gauge, ring gauge.
10) Surface finish- Measurement of surface finish
11) Talysurf surface roughness tester
5. CO-I Know the terms of the measurements, and Understand
the principle of operation of an instrument, Choose Suitable
measuring instruments for a particular application and Apply
ethical principles while measuring dimensions
5
Remember
1.Define Measurement and mention its requirements.
2.Define a) Precision b)Repeatability.
3.Define a) Calibration. b)Threshold
4.Define a) Hysteresis. b)Range
5.Define a)Sensitivity b)Accuracy.
6.Define i) Sensitivity, ii)Accuracy. iii)Calibration
7.Define error and mention types of errors.
8. Name the various types of error.
9.List the various factors in selection of measuring
instruments.
10.State the advantages of CMM.
11.State the types of error.
6. 6
Understand
1.Explain the signification of measurement.
2.Explain the various methods of measurements.
3.Explain the calibration procedure for measuring instrument
4.Explain Systematic and Random Errors.
5.Explain the various methods of measurements with suitable
examples.
6.Explain Taysurf surface roughness testor.
7. 7
Application
1.Explain with neat sketch thread gauge micrometer.
2.Explain with neat sketch measurement of thread by Bench
micrometer.
3.Explain with neat sketch Bevel Protractor.
4.Draw a neat sketch of Bevel Protractor and labels its parts.
5.Explain with neat sketch the use of sine bar.
6.Explain with neat sketch progressive plug gauge.
7.Explain with neat sketch plain plug gauge.
8.Explain with neat sketch snap gauge.
9.Explain with neat sketch Ring gauge.
10.Explain with neat sketch of CMM.
11.Explain with neat sketch thread gauge micrometer. And its
uses.
12. Explain with neat sketch Taysurf surface roughness tester
8. Measurement
8
Measurement means determination of anything that exists in
some amount (Quantity).
If those things that exist are related to mechanical engineering,
then the determination of such amounts are referred to as
mechanical measurements.
Measurement is defined as the process of numerical evaluation
of a dimension or the process of comparison with standard measuring
instruments.
OR
Measurement is defined as the process or the act of obtaining a
quantitative comparison between a predefined standard and an
unknown magnitude.
The basic aim of measurement in industries is to check
whether a component has been manufactured to the
requirement of a specification or not.
9. MEASUREMENTS
9
If the results of the measurement has to
be meaning full, then the following two
conditions has to satisfied.
The standard used for comparison must
be accurately known and internationally
accepted. Example : - A length can not
be simply said too long but it must be
said comparatively longer than some
standard.
The procedure and apparatus used for
comparison must be provable and
10. Methods of Measurements
10
In precision measurement various
methods of measurement are adopted depending
upon the accuracy required and the amount of
permissible (allowable) error. The methods of
measurement can be classified as:
1) Direct method
2) Indirect method
3) Comparative method
4) Coincidence method
5) Deflection method
6) Complementary method
11. 1) DIRECT METHOD OF
MEASUREMENT
11
All the physical dimensions are generally
measured by direct method. This is a simple method of
measurement, in which the value of the quantity to be
measured is obtained directly. It is quite commonly used
for length measurement. For example, measurements by
using scales, vernier calipers, micrometers, bevel
protector etc. This method is most widely used in
production. It is not very accurate because it depends on
human insensitiveness in making judgment.
12. 2) INDIRECT METHOD OF
MEASUREMENT
directly by using some instrument. For example we cannot measure
the strain in the bar. We may have to record the temperature and
pressure in the deep depths of the ground or in some far off remote
places. In such cases indirect methods of measurements are used ,in
indirect method of measurement the value of quantity to be measured
is obtained by measuring other quantities which are functionally
related to it and the required value is obtained by some mathematical
relationship.
In the indirect method of measurements some transducing
devise, called transducer, is used which is coupled to a chain of
apparatus that forms the part of the measuring system. In this system
the quantity which is to be measured (input) is converted into some
other measurable quantity (output) by the transducer. The transducer
used is such that the input and the output are proportional to each
other.
The indirect method of measurements consists of the system
that senses, converts, and finally presents an analogues output in the
form of a displacement or chart. Example:- Angle measurement by
sine bar, measurement of screw pitch diameter by three wire method
12
14. 3) COMPARATIVE METHOD OF
MEASUREMENT
In this method the value of the quantity to be
measured is compared with known value of the same
quantity or other quantity practically related to it. So, in
this method only the deviations from a master gauge are
determined,
For Example :- dial indicators, or other comparators.
14
15. 4) COINCIDENCE METHOD
15
It is a differential method of measurement in which a very
small difference between the value of the quantity to be
measured and the reference is determined by the observation of
the coincidence (alignment) of certain lines or signals. For
example, measurement by vernier caliper micrometer.
16. 5) DEFLECTION METHOD
16
In this method the value of the quantity to be
measured is directly indicated by a deflection of a pointer
on a calibrated scale.
17. 6) COMPLEMENTARY METHOD
17
In this method the value of the quantity to be measured is
combined with a known value of the same quantity. The
combination is so adjusted that the sum of these two values is
equal to predetermined comparison value. For example,
determination of the volume of a solid by liquid displacement.
18. Measurement
18
Measurement provides the fundamental base for
research and development.
Measurement provides the basis for control process.
It helps to achieve the quality of the product.
In process industries, it helps to achieve max
efficiency.
It provides the basis for maintenance of proper
operation.
It increases the consumer confidence.
It helps in maintaining health and safety.
Automatic controls based on measurement.
20. Accuracy
20
The agreement of the measured value with the true
value of the measured quantity is called accuracy.
The term accuracy denotes the closeness of the
measured value with the true value.{ The difference
between the measured value and the true value is the
error of measurement. }The lesser the error, more is
the accuracy.
21. Precision
21
The terms precision and accuracy are used in
connection with the performance of the instrument.
Precision is the repeatability of the measuring process.
It refers to the group of measurements for the same
characteristics taken under identical conditions.
If the instrument is not precise it will give different
(widely varying) results for the same dimension when
measured again and again. The set of observations
will scatter about the mean value. The less the
scattering more precise is the instrument.
22. Sensitivity
22
Sensitivity refers to the ability of measuring device to
detect small differences in a quantity being measured.
For example, if a very small change in voltage is applied to
two voltmeters results in a appreciable change in the
indication of one instrument and not in other, the earlier is
instrument more sensitive.
Or
It is defined as the ratio of the linier movement of the
pointer on the instrument to the change in the
measured variable causing this motion.
The sensitivity of an instrument should be high and the
instrument should not have a range greatly exceeding the
value to be measured, however some clearance should be
kept for any accidental overloads.
Sensitivity and readability are primarily associated
with Equipment while accuracy and precision are
24. Repeatability
24
It is the ability of the measuring instrument to
repeat the same results for the measurements for the
same quantity, when the measurement are carried
out-by the same observer,-with the same instrument,-
under the same conditions and the measurements
are carried out in short intervals of time. It may be
expressed quantitatively in terms of scattering of the
results.
25. Range
25
It represents the highest possible value that can be
measured by an instrument or limits within which
instrument is designed to operate.
26. Threshold
26
Min. value of input required to cause a detectable change from
‘0(zero)’ output.
If input increased gradually from ‘0(zero)’, there will be some
min. value below which no output change can be detected.
If the instrument input increased very gradually from zero,
there will be some min value below which no output change
can be detected. This min value defined as the threshold of the
instrument
27. Hysteresis
27
It is defined as the magnitude of error caused in the out put
for a given value of input ,when this value is measured from
opposite direction, i.e from ascending order and then
descending order. This is caused by backlash, elastic
deformation, magnetic characteristics, but it is mainly
caused by the Frictional effects.
Hysteresis is particularly noted in instruments having elastic
elements. The phenomenon of hysteresis in materials is
mainly due to presence of internal stresses. Which can be
reduced by proper heat treatment process.
Loading
Unloading
Stress
Strain
28. Calibration
28
Calibration is the process of checking the dimension and
tolerances of a gauge, or the accuracy of a measuring
instrument by comparing it to the instrument/gauge that
has been certified as a standard of known accuracy. It is
very much essential to calibrate the instrument so as to
maintain its accuracy.
Calibration of an
instrument is done over
a period of time, which
is decided depending
upon the usage of the
instrument
29. ERRORS IN MEASUREMENTS
29
It is never possible to measure the true value
of a dimension there is always some error. The
error in measurement is the difference between
the measured value and the true value of the
measured dimension.
Error in measurement = Measured value - True
value
30. Classification of Errors
30
Generally errors are classified into two types: systematic
errors, random errors but they are broadly calcified as
follows.
31. Measurement Error
31
The measurement error is the result of the variation of
a measurement of the true value. Usually, Measurement
error consists of a random error and systematic error.
Systematic Errors
The Systematic errors are of constant or similar form,
that occur due to fault in the measuring device or
environmental condition etc. Usually they are called as Zero
Error or a positive or negative error. These errors can be
removed by correcting the measurement device. These
errors may be classified into different categories.
In order to understand the concept of systematic errors,
let us classify the errors as:
Instrumental Errors
Environmental Errors
Observational Errors
32. Instrumental Errors
32
Instrumental errors occur due to wrong
construction of the measuring instrument. These errors
may occur due to hysteresis or friction.
Environmental Errors
The environmental errors occur due to some external
conditions of the instrument. External conditions mainly
include pressure, temperature, humidity or due to magnetic
fields.
Observational Errors
These types of errors occurs due to wrong observations
or reading in the instruments.
33. Random Errors
33
Random errors are caused by the sudden
change in experimental conditions and noise and
tiredness in the working persons. These errors
are either positive or negative. An example of the
random errors is during changes in humidity,
unexpected change in temperature and
fluctuation in voltage. These errors may be
reduced by taking the average of a large number
of readings.
34. Factors in selecting the measuring instruments
34
1. The important charter to be considered in selection of measuring
instrument are its measuring range, Accuracy and Precision.
2. For better results instruments with higher accuracy is selected.
3. Precision is also very important feature for any measuring instrument
because it provides repeatable readings.
4. The sensitivity of that instrument should remain constant through the
range of its measurement.
5. Minimum inertia in the moving parts of the mechanism. The effect of
inertia (ಜಡತ್ವ) is to make the instrument sluggish (slow moving).
6. The time taken to display the final data.(as less as possible).
7. The type of data displayed. (analog or digital or photograph)
8. The cost of measuring instrument.
9. Type of quantity to be measured constant or variable.
10. Nature of quantity being measured hot or cold
11. Resistance to environmental disturbance.
12. Simplicity in calibration when needed.
13. Safety in use.
14. Adoptability to different sizes.
15.
35. Thread measurement
35
Threads are temporary fastener, used to transmit
force and motion.
A screw thread is the helical edge produced by
forming a continuous helical groove of uniform section
on the external or internal surface of a cylinder or a
cone.
There is a large variety of screw threads varying in
their form. The screw threads are mainly classified into
1) External thread 2) Internal thread.
37. 37
Pitch : - It is the distance measured parallel
to the screw threads axis between the
corresponding points on two adjacent
threads in the same axial plane.
Minor diameter : - It is the diameter of an
imaginary co-axial cylinder which touches the
roots of external threads.
Major diameter : - It is the diameter of an
imaginary co-axial cylinder which touches the
crests of an external thread and the root of an
internal thread.
Lead : - The axial distance advanced by the
screw in one revolution is the lead.
Pitch diameter : - It is the diameter at which
the thread space and width are equal to half
of the screw thread
38. 38
Flank angle: It is the angle between the flank and a
line normal to the axis passing through the apex of
the thread.
Height of thread: It is the distance measured radially
between the major and minor diameters
respectively
Addendum: Radial distance between the major and
pitch cylinders for external thread. Radial distance
between the minor and pitch cylinder for internal
thread.
Dedendum: It is the radial distance between the
pitch and minor cylinders for external thread. Also
radial distance between the major and pitch
cylinders for internal thread.
39. Thread measurement
39
To find out the accuracy of a screw thread it will be
necessary to measure the following:
1) Major diameter.
2) Minor diameter.
3) Pitch diameter.
4) Pitch
5) Thread angle
To do this in this chapter we are going to
study two types of thread measuring devices
namely.
1. Thread gauge micrometer
2. Bench micrometer
41. 41
Thread micrometer is used for the measurement of
pitch circle diameter, and the accuracy is very
much dependent on the helix angle of thread.
It is as similar to ordinary micrometer with
difference that it is equipped with a special Vee
shaped anvil and spindle.
The anvil has internal Vee which fits over thread
and free to rotate. Thus the Vee can accumulate
itself to any rake angle range of thread.
The spindle has ground into conical shape, when
the conical spindle brought into contact with Vee of
anvil, micrometer reads zero.
Depending upon the type of threads to be
measured like V-thread, square thread and acme
42. 42
A screw thread micrometer
and its usage is illustrated in
figure. In operation, the zero
setting is checked by bringing the
spindle into the double-vee anvil.
Then, the micrometer is moved on
to the screw thread whose pitch
diameter is to be measured. The
conical shapes of the spindle and
anvil should establish firm contact
with the flanks of the threads and
in this position micrometer
reading should be taken, which
indicates the pitch diameter of the
WORKING PRINCIPLE OF SCREW THREAD
MICROMETER
44. micrometer
44
For getting the greater accuracy the bench micrometer is used
for measuring the major diameter.
In this process the variation in measuring Pressure, pitch
errors are being neglected.
The trustworthy indicator (For Measuring Pressure) is used to
ensure all the measurements are made at same pressure.
The instrument has a micrometer head with a vernier scale to
read the accuracy of 0.002mm. Calibrated setting cylinder
having the same diameter as the major diameter of the
thread to be measured is used as setting standard.
After setting the standard, the setting cylinder is held
between the anvils and the reading is taken
Then the cylinder is replaced by the threaded work piece and
the new reading is taken
46. Angle
measurements
46
Definition of Angle
• Angle is defined as the opening between two lines which
meet at a point.
• If a circle is divided into 360 parts, then each part is called
a degree (o).
• Each degree is subdivided into 60 parts called minutes(’),
and each minute is further subdivided into 60 parts called
seconds(”).
To measure the angle between two
lines or surfaces various angle measuring
instruments are used in which two main
instruments are.
1.Bevel protractor
2.Sine Bar
47. Bevel protractor
47
It is a simplest instrument for measuring the angle
between two faces of a component.
It consists of a base plate attached to a main body
and an adjustable blade which is attached to a circular
plate containing vernier scale.
The adjustable blade is capable of sliding freely along
the groove provided on it and can be clamped at any
48. Working principle
48
A vernier bevel protractor is attached with acute angle
attachment. The body is designed like its back face is flat and
no projections beyond its back. The base plate is attached to
the main body and an adjustable blade is attached to the
circular plate containing Vernier scale. The main scale is
graduated in degrees from 0° to 90° in both the directions.
The adjustable blade can be made to rotate freely about the
center of the main scale and it can be locked at any position.
For measuring acute angle, a special attachment is
provided. The base plate is made flat for measuring angles
and can be moved throughout its length. The ends of the
blade are beveled at angles of 45° and 60°. The main scale
is graduated as one main scale division is 1° and Vernier is
graduated into 12 divisions on each side of zero. Therefore
the least count is calculated as
Least count = One main scale division = 1 Degree= (1/12) x 60 Min =
5 Minutes
49. Applications of bevel protractor
49
The bevel protractor can be used in the following
applications.
50. SINE BAR
50
Sine bars are always used along with slip gauges
as a device for the measurement of angles very
precisely. They are used to
1) Measure angles very accurately.
2) Locate the work piece to a given angle with very high
precision.
51. 51
Generally, sine bars are made from high carbon,
high chromium, and corrosion resistant steel. These
materials are highly hardened, ground and stabilized.
In sine bars, two cylinders of equal diameter are
attached at lie ends with its axis are mutually parallel to
each other. They are also at equal distance from the
upper surface of the sine bar mostly the distance
between the axes of two cylinders is 100mm, 200mm
or 300mm. The cylindrical holes are provided to reduce
the weight of the sine bar.
52. Working principle of sine bar
52
1) Before checking the unknown angle of the specimen,
first the angle (x0)of given specimen is found
approximately by bevel protractor.
2) Then the sine bar is set at angle of (x0) and clamped
on the angle plate.
3) Now, the work is placed on the sine bar and the dial
indicator set at one end of the work piece and is moved
across the work piece and deviation is noted.
4) Slip gauges are adjusted so that the dial indicator
reads zero throughout the work surface.
53. Gauges
53
Gauges are inspection tools which serve to check
the dimensions of the manufactured parts. Limit
gauges ensure the size of the component lies within
the specified limits. They are non-recording and do not
determine the size of the part.
The common types are as follows:
1) Plain Plug gauges.
2) Ring gauges.
3) Snap gauges.
54. Plain Plug gauges
54
Plug gauges are the limit gauges used for checking
holes and consist of two cylindrical wear resistant
plugs. The plug made to the lower limit of the hole is
known as ‘GO’ end and this will enter any hole which is
not smaller than the lower limit allowed. The plug made
to the upper limit of the hole is known as ‘NO GO’ end
and this will not enter any hole which is smaller than
the upper limit allowed. The plugs are arranged on
either ends of a common handle.
Plug gauges are normally double ended for sizes
up to 63 mm and for sizes above 63 mm they are single
ended type.
55. Ring gauges
55
Ring gauges are mainly used for checking the
diameter of shafts having a central hole. The hole is
accurately finished by grinding and lapping after taking
hardening process. The periphery of the ring is knurled to
give more grips while handling the gauges. We have to
make two ring gauges separately to check the shaft such
as GO ring gauge and NOGO ring gauge. But the hole of
GO ring gauge is made to the upper limit size of the shaft
and NOGO for the lower limit. While checking the shaft, the
GO ring gauge will pass through the shaft and NOGO will
not pass. To identify the NOGO ring gauges easily, a red
mark or a small groove cut on its periphery.
56. Snap gauges
56
A snap gauge usually consists of a plate or frame
with a parallel faced gap of the required dimension.
Snap gauges can be used for both cylindrical as well as
non cylindrical work as compared to ring gauges which
are conveniently used only for cylindrical work. Double
ended snap gauges can be used for sizes ranging from
3 to 100 mm. For sizes above 100 mm up to 250 mm a
single ended progressive gauge may be used.
57. Surface finish
57
As we know that any material being machined by chip
removal process which can’t be finished perfectly due to
some change in ideal condition.
The degree of smoothness of a part’s surface after it has
been manufactured. Surface finish is the result of the
surface roughness, waviness and flaws remaining on
the part.
58. Terminology related Surface
Roughness
58
Surface Roughness
Surface roughness is a property of the material surface texture,
which is recognized by an uneven texture surface as compared to an
ideal flat surface. A rough surface is identified by finely spaced
irregularities, protuberances, or ridges.
Surface Waviness
Waviness can be distinguished from roughness by the broader
spacing between the surface irregularities. Heat treatment, residual
stress, and vibrations are some the common causes for waviness of
surface texture.
Lay
Lay is defined as the direction of the predominant surface pattern.
Roughness Height
Roughness height is a measure of the height of the irregularities
compared to a reference line.
Roughness Width
Roughness width is the distance between the two successive
60. 60
The Talysurf is an electronic instrument working
on carrier modulating principle. This instrument records the
static displacement of the stylus and is dynamic instrument
like profilometer.
The measuring head of this instrument consists of a
diamond stylus of about 0.002 mm tip radius and skid or
shoe which is drawn across the surface by means of a
motorized driving unit (gearbox), which provides three
motorized speeds and a speed suitable for average reading.
A neutral position in which the pick-up can be traversed
manually is also provided. In this case the arm carrying the
stylus forms an armature which pivots about the centre piece
of E-shaped stamping as shown in Fig. On two legs of (outer
pole pieces) the E-shaped stamping there are coils carrying
an a.c. current. These two coils with other two resistances
form an oscillator. As the armature is pivoted about the
central leg, any movement of the stylus causes the air gap to
vary current and thus the amplitude of the original a.c.
61. 61
This is further demodulated so that the current
now is directly proportional to the vertical
displacement of the stylus only. The demodulated
output is caused to operate a pen recorder to produce
a permanent record and a meter to give a numerical
measurement directly.
Now-a-days microprocessors have made
available complete measuring at several places over
a given area and can provide standard deviations and
average value.
63. 63
Coordinate Measuring Machine (CMM) is a 3-
dimensional measuring device that uses a contact
probe to detect the surface of the object. The
measuring head incorporates a probe tip, which can
be of different kinds like taper tip, ball tip etc ,The
probe is generally a highly sensitive pressure
sensing device that is triggered by any contact with a
surface. The linear distances moved along the 3
axes are recorded, thus providing the x, y and z
coordinates of the point. CMMs are classified as
either vertical or horizontal, according to the
orientation of the probe with respect to the
measuring table.
These are manufactured in both manual and
computer-controlled models and come in a wide
range of sizes to accommodate a variety of
