Jet engines create forward thrust by taking in a large amount of air and discharging it as a high-speed jet of gas. The way they’re designed allows aircraft to fly faster and further compared to propeller-driven aircraft. Their development and refinement over the course of the last 65 years has made commercial air travel more practical and profitable, opening the world to business and recreational travelers.
Monday, 2 December 2013
Sunday, 4 August 2013
Sunday, 9 June 2013
HYDRAULIC JACK or HYDRAULIC PRESS
HYDRAULIC JACK or HYDRAULIC PRESS
The hydraulic jack is a device used for lifting heavy loads by the application of much smaller force. It is based on Pascal’s law, which states that intensity of pressure is transmitted equally in all directions through a mass of fluid at rest.
WORKING PRINCIPLE: The working principle of a hydraulic jack may be explained with the help of Fig. 23. Consider a ram and plunger, operating in two cylinders of different diameters, which are interconnected at the bottom, through a chamber, which is filled with some liquid.
Fig. Hydraulic jack Fig. Plunger
Let
W= Weight to be lifted,
F = Force applied on the plunger,
A = Area of ram, and
a = Area of plunger.
Pressure intensity produced by the force F, p = F/Area of plunger = F/a
As per Pascal’s law, the above intensity p will be equally transmitted in all directions.
Therefore, The pressure intensity on ram = p = F/a = W/A or W= F(A/a)
Above Equation indicates that by applying a small force F on the plunger, a large force W may be developed by the ram.
Mechanical advantage of press = A/a
If the force in the plunger is applied by a lever which has a mechanical advantage (L/l) then total mechanical advantage of machine = (L/l)(A/a)
The ratio (L/l) is known as leverage of press.
Hydraulic jack may be employed for the following jobs:
The hydraulic jack is a device used for lifting heavy loads by the application of much smaller force. It is based on Pascal’s law, which states that intensity of pressure is transmitted equally in all directions through a mass of fluid at rest.
WORKING PRINCIPLE: The working principle of a hydraulic jack may be explained with the help of Fig. 23. Consider a ram and plunger, operating in two cylinders of different diameters, which are interconnected at the bottom, through a chamber, which is filled with some liquid.
Fig. Hydraulic jack Fig. Plunger
Let
W= Weight to be lifted,
F = Force applied on the plunger,
A = Area of ram, and
a = Area of plunger.
Pressure intensity produced by the force F, p = F/Area of plunger = F/a
As per Pascal’s law, the above intensity p will be equally transmitted in all directions.
Therefore, The pressure intensity on ram = p = F/a = W/A or W= F(A/a)
Above Equation indicates that by applying a small force F on the plunger, a large force W may be developed by the ram.
Mechanical advantage of press = A/a
If the force in the plunger is applied by a lever which has a mechanical advantage (L/l) then total mechanical advantage of machine = (L/l)(A/a)
The ratio (L/l) is known as leverage of press.
Hydraulic jack may be employed for the following jobs:
- Metal press work (to press sheet metal to any required shape).
- Drawing and pushing rods.
- Bending and straightening any metal piece .
- Packing press
Saturday, 25 May 2013
The Basic Concept, Construction, and Working Principle of Hydraulic Pumps
Basic Concept of a Pump
A pump in general is a machine which imparts energy to anything flowing through it. This can be any fluid, heat or even electrons. The devices pumping heat are called as heat pumps and electrical batteries can pump electrons. The spontaneous tendency of anything is to flow from high potential to low potential and this natural tendency is harnessed in many applications. But the pump does exactly the reverse; it forces something to move from low potential to high potential. For this purpose pumps use energy and by their functioning transfer that energy to the substance flowing through them.Fluid pumps or Hydraulic pumps move fluids and displace them from one position to another and in course energizes them. In fluids this energy is manifested as its pressure and velocity. Similarly, heat pumps move heat from low temperature to high temperature against its natural tendency to flow from high temperature to low temperature. An electrical battery is also a type of pump; it pumps electrons in a circuit from low electrical potential to high electrical potential which is against the spontaneous tendency of electrons to move from high electrical potential to low electrical potential. Hence, an electrical battery can be called as an Electron Pump.
Hydraulic Pump Construction
Basically
a fluid pump or hydraulic pump is a device or machine having moving
mechanical components which uses energy from some source, generally
electrical, supplied to it in form of mechanical energy by electrical
motor.Generally pumps have rotating parts run by the electrical motors. The rotating parts of pumps can be some volume defining components which can form an enclosed envelope of volume where the fluid can captured and displaced. Other type of rotating parts can be blades mounted on discs or shafts which rotate with the driving power and transfers that to the fluid by making it move with increased velocity.
Basic Working Principle
In simple words we consider a pump to be a black box to understand its working. Fluid enters a pump at certain velocity and pressure, which may be even zero, and leaves it with increased energy, that is, velocity and pressure. For this a pump consumes a certain amount of energy from any external source. Now, what is happening inside that black box? There are rotating components inside which move the fluid either by confining it in definite volumes and then displacing it or by imparting energy to the fluid by dynamic action of the moving parts and increasing velocity and pressure of the fluid.Fluid Pumps
Fluid
Pump or Hydraulic Pump is a machine which transfers the energy from its
moving parts to the fluid passing through the machine. The energy
transferred from the Pump to the fluid appears as the pressure and
velocity of the fluid. Know more about Fluid or Hydraulic Pumps in this
article series.
Thursday, 25 October 2012
simple machines
Simple machines
A simple machine is a device that requires only the force of a human to perform work. One of
the properties of a simple machine is that it can be used to increase the force that can be applied
to a task.
Law of Simple Machines
Resistance Force x resistance distance = effort force x effort distance
The Mechanical Advantage is the ratio of the resistance force to the effort force
resistance force
effort force
MA =
There are four types of simple machines: the lever, the inclined plane (the wedge and the screw
are special cases of the inclined plane), the pulley, the wheel and axle (including the gear).
The Lever
The lever is a simple machine consisting of a rigid bar that is free to pivot on a fulcrum.
Depending on the position of the force (F), the load or resistance (R) and the fulcrum, there are
three classes of levers:
First Class Lever
Second Class Lever
Third Class Lever
F Fulcrum
R
F R
Fulcrum
F
R
Fulcrum
Simple Machines1.doc
Physics ~
First Class Level
The fulcrum is between the force and the load. This is the most common arrangement. The
mechanical advantage of this lever depends upon where we place the fulcrum. If the fulcrum is
closer to the load, the mechanical advantage is higher.
Examples of this class are the seesaw, the rows in a boat, etc.
Second Class Level
Here the load ( R ) is between the force and the fulcrum. The mechanical advantage of this type
of lever depends upon the placement of the load. It is greater when the load is closer to the
fulcrum. When the load is closer to the force, the mechanical advantage approaches to one, so no
mechanical advantage at all.
Examples of this class are: the wheelbarrow, the stapler, the nutcracker, etc
(*) Notice that the distance is always measured from the force (or load) to the fulcrum no matter where it
is located.
Force
Fulcrum
1 d 2 d
Force Fulcrum
1 d
2 d
1 2 F ⋅ d = R ⋅ d
pulley MA
d
d
F
R = =
2
1
1 2 F ⋅ d = R ⋅ d
pulley MA
d
d
F
R = =
2
1
(*)
(*)
R F
F
MA R pulley = = 1 ⇒ =
Simple Machines1.doc
Physics ~ ASC 2005
- 3 -
Third Class Level
In this class the force is between the fulcrum and the load (R ). The human forearm is a third
class lever. The elbow is the fulcrum, and the forearm muscles apply the effort between the
elbow and hand. Tweezers, tongs, and the fishing rod are examples of this type. Levers of this
class are used less often because their mechanical advantage is less than one; this means that the
force needed to use them is greater than the force they can move.
The Inclined Plane
The inclined plane is a simple machine, consisting of a sloping surface, which has some angle
above or below the horizontal used to raise objects that are too heavy to lift vertically.
Gangways, chutes, and ramps are all examples of the inclined plane.
Switchbacks on mountain roads are also examples of inclined planes that reduce the effort of an
automobile engine but increase the distance a car must travel to ascend the mountain.
The inclined plane has been modified in many ways. The screw and wedge are applications
of the principle behind the inclined plane but do not require that the load be moved vertically
for their successful operation.
• The screw consists essentially of a solid cylinder, usually of metal, around which
an inclined plane winds spirally, either clockwise or counterclockwise. It is used
1 d
2 d
Load ( R )
Force Fulcrum
Force
Load(R)
Force Distance
Load
Distance
inclined plane MA
height of plane
lenght of plane
F
R = =
pulley MA
d
d
F
R = =
2
1
1 2 F ⋅ d = R ⋅ d
d1 d2
1 2 F ⋅ d = R ⋅ d
Simple Machines1.doc
Physics ~ ASC 2005
- 4 -
to fasten one object to another, to lift a heavy object, or to move an object by a
precise amount.
• The wedge shape has a triangular cross-section. It may be used to lever, split, or
tighten.
The Pulley
The pulley is a simple machine, consisting of a wheel that rotates around a stationary axle. The
outer rim of the pulley is grooved to accommodate a rope or chain. Pulleys are used for lifting by
attaching one end of the rope to the object, threading the rope through the pulley (or system of
pulleys), and pulling on the other end of the rope.
A single, fixed pulley just changes the direction of the applied force and make it easier to lift the
load, since a person can pull down on a rope, rather than simply lifting the load. A common
example of a pulley can be found at the top of a flagpole. .
Pulleys reduce the effort needed to lift an object by increasing the distance over which the effort
is applied
The law of simple machines as applied to pulleys:
R. dR = F. dF
Where d refers to the distance moved, not the diameter of the pulley
So, we can say
When one continuous cord is used, this ratio reduces to the number of strands holding the
resistant in the pulley system,
Force
Load
Force
Load
F
R
dF
dR
pulley
R
F MA
d
d
F
R = =
Simple Machines1.doc
Physics ~ ASC 2005
- 5 -
MApulley = Number of strands holding the resistance
The resistance force (R) is spread equally among the supporting strands.
Therefore, R = n T, where n is the number of strands holding the resistance and T is the tension
in each supporting strand.
The effort force (F) is equal to the tension in each supporting strand , so
The wheel-and-axle
This simple machine is a wheel attached rigidly upon an axle or drum of smaller diameter; the
wheel and the axle have the same axis, so that both can turn together.
The law of simple machines as applied to wheel-and-axle is
R . rR = F. rF
where:
R = resistance force
rR = radius of resistance wheel
F = effort force
rF = radius of resistance wheel
Examples are the steering wheel of an automobile, the doorknob, the tires and the casters.
n
T
nT
F
MA R pulley = = =
rR
rF
R
F
R
F
wheel and axle r
r
radius of resis ce force
MA = = radius of effort force = − − resisttaannce
Wednesday, 17 October 2012
THEORY OF MACHINES
THEORY OF MACHINES
RATIONALE
Diploma holder in Mechanical Engineering comes across many machines. He must have
the knowledge of various mechanisms, power transmission devices, balancing of masses,
vibrations etc. Hence this subject is offered.
DETAILED CONTENTS
1. Basic Concepts
1.1 Definition of statics, kinetics, kinematics and dynamics.
1.2 Rigid body and resistant body.
1.3 Links.
1.4 Kinematics pairs and their types.
1.5 Degree of freedom.
1.6 Kinematics chain and their types.
1.7 Constrained motion and mechanisms.
1.8 Classification of mechanisms.
1.9 Equivalent mechanism.
1.10 Laws of inversion of mechanisms.
1.11 Single slider crank chain and its inversions.
1.12 Quick return mechanism and IC engine mechanism.
1.13 Double slider crank chain mechanism and its inversions like scotch yoke
mechanism.
1.14 Applications of mechanisms and their selection from manufacture
catalogue.
1.15 Indicator mechanism, pantograph.
1.16 Steering gear mechanism.
2. Fly Wheel
2.1 Functions of fly wheel.
2.2 Types of fly wheels.
2.3 Mass and size calculations in different cases
3. Governors
3.1 Functions of governor
3.2 Types of governor - elementary knowledge of porter governor, watt
governor, proell governor, Hartnell governor, spring controlled gravity
governor
3.3 Hunting, isochronism, stability, sensitiveness of a governor
3.4 Simple problems related to watt, porter and proell governor
4. Cams
4.1 Definition of cam
4.2 Classification of cams
4.3 Followers and their classification
4.4 Brief description of different types of cams and followers with simple line
diagram
4.5 Simple cam profile for uniform velocity, SHM and uniform acceleration
and deceleration
5. Power Transmission Devices (Belt, Rope and Chain Drive)
5.1 Introduction.
5.2 Belt and rope drives, open and crossed belt drives, action of belt on
pulleys, velocity ratio.
5.3 Material for belts and ropes.
5.4 Slip in belts, ropes, and chains.
5.5 Types of V Belt and Flat belt, joint preparation for flat belt.
5.6 Types of pulleys - step pulley, flat pulley, jockey pulley.
5.7 Crowning in pulley.
5.8 Laws of belting and length of belt
5.9 Ratio of tensions
5.10 Power transmitted and maximum power transmitted by belt
5.11 Centrifugal effect on belt
5.12 Initial tension, creep
5.13 Chain drive, chain length, classification of chains
5.14 Selection of belt, chain and pulley for different applications on the basis of
centre distance between the shaft, power to be transmitted, availability of
space, slip, velocity ratio
5.15 Selection of rope based on the load to be lifted
5.16 Simple problems on power transmitted by belts and ropes
6. Gear Drive
6.1 Functions of gear
6.2 Classification of gears
6.3 Gear nomenclature
6.4 Simple, compound, reverted and epicyclic
6.5 Horsepower transmitted by a gear train
6.6 Selection of gear trains- simple and epicyclic
7. Brakes and Dynamometers
7.1 Introduction
7.2 Brief description of different types of brake such as block or shoe brake,
band brake, internal expanding,power brake and disc brake
7.3 Simple problems related to shoe brake and band brake
7.4 Definition and types of dynamometers, pony brake dynamometer, rope
brake dynamometers, hydraulic dynamometer, belt transmission
dynamometer and Bevis Gibson torsion dynamometer
8. Clutches
8.1 Function of clutch
8.2 Classification of clutches
8.3 Principle of working of single plate clutch and cone clutch with simple line
diagram
8.4 Multi plate clutch
8.5 Calculation of frictional torque for uniform pressure and uniform wear
8.6 Horse power transmitted
8.7 Selection of clutches for different applications from hand book/catalogue
9. Balancing
9.1 Need of balancing
9.2 Concept of static and dynamic balancing
9.3 Balancing of rotating mass by another mass in the same plane
9.4 Forces due to revolving masses
9.5 Concept of reference plane
9.6 Balancing of several masses rotating in same plane
9.7 Balancing of several masses rotating in different planes
10. Vibrations
10.1 Introduction
10.2 Types of vibration - longitudinal, transverse and torsional vibration
10.3 Damping of vibrations
INSTRUCTIONAL STRATEGY
1. Use teaching aids for classroom teaching.
2. Give assignments for solving numerical problems.
3. Arrange industry visits to augment explaining use of various machine components
like belt, rope, chain, gear drives, action due to unbalanced masses, brake clutch,
governors, fly wheels, cams and gear drives.
4. Video films may be used to explain the working of mechanisms and machine
components like clutch, governors, brake etc.
RECOMMENDED BOOKS
1. Mechanism and Machine Theory; JS Rao and Dukkipati; Wiley Eastern, New
Delhi.
2. Theory of Mechanism and Machine; A Ghosh and AK Malik, East West Press
(Pvt.) Ltd., New Delhi.
3. Theory of Machines; SS Rattan: Tata McGraw Hill, New Delhi.
.
4. Theory of Machines by RS Khurmi and JK Gupta; S.Chand and Company Ltd.,
New Delhi.
5. Theory of Machines and Mechanisms by PL Ballaney; Khanna Publishers, New
Delhi.
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 6 10
2. 8 12
3. 8 12
4. 8 12
5. 8 12
6. 8 12
7. 4 6
8. 4 6
9. 8 12
10. 2 6
Total 64 100
METROLOGY
L T P
3 - 2
RATIONALE
Diploma holders in these courses are required to measure and inspect for ensuring quality
of product. For this purpose, knowledge and skills about standards of measurement, limit,
fits and tolerances, types of inspection and various measuring instruments are required.
Hence this subject is offered
DETAILED CONTENTS
1. Introduction
1.1 Definition of metrology
1.2 Standard of measurement
1.3 Types of errors- Controllable and random errors
1.4 Precision, accuracy, sensitivity, hysterisis, response time, repeatability,
calibration, uncertainty of measurement
2. Linear Measurement
2.1 Construction features and use of instruments for non precision linear
measurement: steel rule, callipers, surface plate, angle plate, V-block.
2.2 Construction features and use of instruments for precision measurements :
vernier calipers, vernier height and depth gauges, micrometers.
2.3 Slip gauges, Indian standards of slip gauges, sets of slip gauges, use of slip
gauges.
2.4 Cylinder bore gauges, feeler and wire gauges.
2.5 Comparators – Characteristics, uses, working principles of different types
of comparators: mechanical, electrical, electronics and pneumatic
comparator.
3. Angular Measurement
3.1 Construction and use of instruments for angular measurements: bevel
protector, sine bar, angle gauges, clinometer.
3.2 Optical instruments for angular measurement, auto collimator.
4. Measurement of Surface Finish
4.1 Terminology of surface roughness.
4.2 Concept of primary texture and secondary texture.
4.3 Factors affecting surface finish.
4.4 CLA, RMS and RA value.
4.5 Principle and operation of stylus probe instruments for measuring surface
roughness
5. Measurements of Screw threads and Gears
5.1 Measurement of screw threads- Introduction, measurements of external
and core diameters, checking of pitch and angle of threads with gauges.
5.2 Effective diameter measurement by three wire method.
5.3 Measurements of gears (spur) – Measurement of tooth thickness, pitch,
testing of alignment of teeth.
5.4 Profile projector, Coordinate Measuring Machine (CMM), Tool maker’s
microscope.
6. Machine Tool Testing
6.1 Alignment test on lathe, drilling machine and milling machine.
7. Limits, Fits and Tolerances
7.1 Definition and terminology of limits, fits and tolerances.
7.2 Hole basis and shaft basis systems.
7.3 Type of fits.
7.4 Limit gauges.
8. Instrumentation
Brief description about the measurement of displacement, vibration, frequency,
pressure, temperature and humidity by electromechanical transducers
LIST OF PRACTICALS
1. Internal and external measurement with vernier caliper and micrometer.
2. Measurement with height gauge and depth gauge.
3. Measurement of flatness with dial indicator.
4. Measurement with combination set and bevel protector.
5. Study and use of slip gauges.
6. Measurement of gear characteristics
7. Measurement of angle with sine bar and slip gauges
8. Measurement of worn out IC engine piston clearance between cylinder and piston.
9. Measurement of flatness using comparator.
10. Determination of temperature by (i) pyrometer (ii) thermocouple.
11. Use of feeler gauge, wire gauge , radius gauge and fillet gauges for checking of
standard parameters.
12. Measurement of surface roughness of a surface
INSTRUCTIONAL STRATEGY
1. Demonstrate use of various measuring instruments while imparting theoretical
instructions.
2. Stress should be laid on correct use of various instruments.
RECOMMENDED BOOKS
1. Engineering Metrology by RK Jain; Khanna Publishers, New Delhi.
2. A Text Book of Production Engineering by PC Sharma; S Chand and Company,
New Delhi.
3. Metrology Laboratory Manual by M Adithan and R Bahl; NITTTR, Chandigarh.
4. Engineering Metrology by RK Rajput; SK Kataria and Sons, Ludhiana.
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 4 10
2. 8 18
3. 7 14
4. 6 12
5. 6 12
6. 6 12
7. 5 10
8. 6 12
Total 48 100
PRODUCTION TECHNOLOGY- I
L T P
3 - 6
RATIONALE
This subject provides knowledge and develops skills on various machine operations viz
capstan and turret Lathe, milling, grinding, gear manufacturing, broaching and automatic
machines which is very essential for Mechanical diploma holders to work in
manufacturing industries
DETAILED CONTENTS
1. Capstan and Turret Lathe
1.1 Concept of capstan and turret lathe
1.2 Principal parts of capstan and turret lathe
1.3 Turret indexing mechanism, Bar feeding mechanism
1.4 Work holding devices – Jaw and collet chucks
1.5 Tool holding devices – Slide tool holder, Knee tool holder, knurling tool
holder, recessing tool holder, form tool holder, tap and die holder, Vsteady
box tool holder, roller steady, box tool holder, bar stops.
1.6 Introduction to turret tooling layout
1.7 Comparison of capstan, turret and conventional lathe.
2. Milling
2.1 Specification and working principle of milling machine
2.2 Classification, brief description and applications of milling machines
2.3 Details of column and knee type milling machine
2.4 Milling machine accessories and attachment – Arbors, adaptors, collets,
vices, circular table, indexing head and tail stock, vertical milling
attachment, spiral milling attachment, slotting attachment and rack milling
attachment.
2.5 Milling methods - up milling and down milling
2.6 Identification of different milling cutters and work mandrels
2.7 Work holding devices
2.8 Milling operations – face milling, angular milling, form milling, straddle
milling and gang milling.
2.9 Cutting speed and feed, simple numerical problems.
2.10 Indexing on dividing heads, plain and universal dividing heads.
3. Grinding
3.1 Purpose of grinding
3.2 Various elements of grinding wheel – Abrasive, Grade, structure, Bond
3.3 Common wheel shapes and types of wheel – built up wheels, mounted
wheels and diamond wheels. Specification of grinding wheels as per BIS.
3.4 Truing, dressing, balancing and mounting of wheel.
3.5 Grinding methods – Surface grinding, cylindrical grinding and centreless
grinding.
3.6 Grinding machine – Cylindrical grinder, surface grinder, internal grinder,
centreless grinder, tool and cutter grinder.
3.7 Selection of grinding wheel
4. Gear Manufacturing Processes
4.1 Gear hobbing
4.2 Gear shaping
5. Broaching
5.1 Introduction
5.2 Types of broaching machines – Single ram and duplex ram horizontal type,
vertical type pull up, pull down, push down.
5.3 Elements of broach tool, broach teeth details – nomenclature, types, tool
material.
PRACTICAL EXERCISES
1. Exercise on Turrent/ Capstan Lathe to prepare a job of given dimensions
2. To produce a rectangular block by face milling and prepare a slot on one face.
3. Exercise on milling- slab milling, Gang milling and straddle milling
4. To produce a gear by indexing device on a milling machine
5. Preparing job on following machines:-
a) Surface grinder
b) Cylindrical grinder
6. Exercise on tool and cutter Grinder
a) To grind Lathe tools
b) To grind a drill bit
c) To grind a milling cutter
INSTRUCTIONAL STRATEGY
1. Teaches should lay special emphasis in making the students conversant with
concept, principle, procedure and practices related to various manufacturing
processes
2. Focus should be laid on preparing jobs using various machines/ equipment in
the workshop
3. Aids/ Video films should be used to show operations
RECOMMENDED BOOKS
1. Manufacturing technology by Rao; Tata McGraw hill Publishers, New Delhi
2. Manufacturing technology by M. Adithan and AB. Gupta; New Age International
(P) Ltd, New Delhi
3. Workshop Technology vol I, II, III by Champman; Standard publishers
Distributors
4. Practical hand book for Mechanical Engineers by AB Gupta; Galgotia
publications, New Delhi
5. Production technology by HMT, Tata McGraw Publishers; New Delhi
6. Principle of metal cutting by Bhattacharya, Standard publishers Distributors,
New Delhi
7. Fundamentals of metal cutting and machine tools by Juneja and Sekhon; Wiley
Eastern Ltd., New Delhi
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 12 28
2. 12 28
3. 8 12
4. 10 20
5. 6 12
Total 48 100
COMPUTER AIDED DRAFTING
L T P
- - 6
1. Introduction to AutoCAD commands
1.1 Concept of AutoCAD, Tool bars in Auto CAD, coordinate system, snap,
grid, and ortho mode
1.2 Drawing commands – point, line, arc, circle, ellipse,
1.3 Editing commands – scale, erase, copy, stretch, lengthen and explode.
1.4 Dimensioning and placing text in drawing area
1.5 Sectioning and hatching
1.6 Inquiry for different parameters of drawing entity
2. Assembly and detail drawings of the following using AUTOCAD (9 sheets)
2.1 Tool post
2.2 Tail stock
2.3 Screw jack
2.4 Safety valve
2.5 Stuffing Box
2.6 Bench vice
3. Isometric Drawings by CAD
Drawings of following on computer:
- Cone
- Cylinder
- Isometric view of objects
4. 3D Modelling
3D modelling, Transformations, scaling, rotation, translation
INSTRUCTIONAL STRATEGY
1. Teachers should show model or realia of the component/part whose drawing is to be
made.
2. Emphasis should be given on cleanliness, dimensioning, layout of sheet.
3. Teachers should ensure use of IS codes related to drawing.
RECOMMENDED BOOKS
1. AutoCAD 2000 for you by Umesh Shettigar and Abdul Khader; Janatha
Publishers, Udupi.
2. Machine Drawing by P.S. Gill; Kataria and Sons, Ludhiana.
3. A Text book of Machine Drawing by R.K. Dhawan , S.Chand and Company Ltd.,
New Delhi.
4. Engineering Drawing with AutoCAD 2000 by T. Jeyapooran; Vikas Publishing
House, Delhi.
5. AutoCAD for Engineering Drawing Made Easy by P. Nageswara Rao; Tata
McGraw Hill, New Delhi.
MACHINE DESIGN
L T P
4 - -
RATIONALE
The contents of this subject are organised to understand the intricacies of different
engineering design aspects. This will also help the students to enhance their imagination,
innovative skill, adaptability to new situation and continued learning skills for problem
solving.
DETAILED CONTENTS
1. Introduction
1.1 Design – Definition, Type of design, necessity of design
1.1.1 Comparison of designed and undesigned work
1.1.2 Design procedure
1.1.3 Practical examples related with design procedure
1.1.4 Characteristics of a good designer
1.1.5 Characteristics of environment required for a designer
1.2 Design terminology: stress, strain, factor of safety, factors affecting factor
of safety, stress concentration, methods to reduce stress concentration,
fatigue, endurance limit. General design considerations
1.3 Engineering materials and their mechanical properties :
1.3.1 Properties of engineering materials: elasticity, plasticity,
malleability, ductility, toughness, hardness and resilience. Fatigue,
creep, tenacity, strength
1.3.2 Selection of materials, criterion of material selection
2. Design Failure
2.1 Various design failures
- Maximum principal stress theory.
- Maximum shear stress theory
- Maximum strain theory
2.2 Design for tensile, compressive and torsional loading
2.3 Design for combined torsion and bending
3. Design of Shaft
3.1 Type of shaft, shaft materials, Type of loading on shaft, standard sizes of
shaft available
3.2 Shaft subjected to torsion only, determination of shaft diameter on the
basis of :
- Strength criterion
- Rigidity criterion
3.3 Shaft subjected to bending
3.4 Shaft subjected to combined torsion and bending
4. Design of Key
4.1 Types of key, materials of key, functions of key
4.2 Failure of key (by Shearing and Crushing).
4.3 Design of key (Determination of key dimension)
4.4 Effect of keyway on shaft strength. (Figures and problems).
5. Design of Joints
Types of joints - Temporary and Permanent, utility of joints
5.1 Temporary Joint:
5.1.1 Knuckle Joints – Different parts of the joint, material used for the
joint, type of knuckle Joint, design of the knuckle joint. (Figures
and problems).
5.1.2 Cotter Joint – Different parts of the joint, type of cotter joint –
spigot and socket joint, gib and cotter joint, sleeve and cotter joint,
Design of cotter joint (Figures and problems).
5.2 Permanent Joint:
Welding symbols, standards and materials having high weldability.
5.2.1 Welded Joint - Type of welded joint, strength of parallel and
transverse fillet welds.
5.2.2 Strength of combined parallel and transverse weld.
5.2.3 Axially loaded welded joints.
5.2.4 Riveted Joints. : Rivet materials, Rivet heads, leak proofing of
riveted joint – caulking and fullering.
5.2.5 Different modes of rivet joint failure.
5.2.6 Design of riveted joint – Lap and butt, single and multi riveted
joint, Diamond (Lozenzo) joint, circumferential and longitudinal
boiler joints
6. Design of Flange Coupling
Necessity of a coupling, advantages of a coupling, types of couplings, design of
flange coupling. (both protected type and unprotected type).
7. Design of Pulley
7.1 Types of pulley, crowning of pulley, pulley materials, components of a
pulley.
7.2 Determination of pulley dimensions (Figures and problems).
8. Design of Screw, Nut, Bolt and Thread
8.1 Form of thread (ISO), Type of nut heads, type of threads and their
nomenclature.
8.2 Nature of loads on nut and bolts, types of failure of nut and bolts.
8.3. Initial stresses due to screwing up, stresses due to combination of different
loads.
.
INSTRUCTIONAL STREATEGY
1. Use models of machine parts/components.
2. Presentation should be arranged for various topics.
REFERENCE BOOKS
1. Machine Design by R.S. Khurmi and JK Gupta; Eurasia Publishing House (Pvt.)
Limited, New Delhi.
2. Machine Design by V.B.Bhandari; Tata McGraw Hill, New Delhi.
3. Machine design by R.A Agarwal; Nav Bharat parkashan, Meerut.
4. Machine Design by Sharma and Agrawal; Katson Publishing House, Ludhiana.
5. Machine design by J.K. Kapoor, B. Bharat Parkashan, Meerut.
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 6 10
2. 3 5
3. 14 22
4. 4 6
5. 20 30
6. 6 10
7. 3 5
8. 8 12
Total 64 100
CNC MACHINES AND AUTOMATION
L T P
3 - 4
RATIONALE
Students are required to supervise and handle specialized machines and equipments like
CNC machines. This subject aims at development of knowledge and skill about CNC
machines tools, equipment and use of high tech. machines
DETAILED CONTENTS
1. Automation
1.1 Definition
1.2 Types of Automation
1.3 Need of Automation
1.4 Advantages of Automation
2. Introduction to Numerical Control
Computer applications in manufacturing, basic concepts of NC, CNC, DNC and
adaptive control, advantages and application of CNC machines in industry
3. Components of CNC System
Machine control unit, NC control and PLC control system, introduction to C axis
and special constructional requirements of CNC machines, machine bed, slide
ways, bolt, screw and nut assembly, lubrication and cooling system, spindle and
spindle motors, axis drive motors, automatic tool changers, multiple pallets, swarf
removal mechanisms and safety provision
4. Part Programming
Part programming and basic concepts of part programming, NC words, part
programming formats, simple programming for rotational components, part
programming using canned cycles, subroutines and do loops, tool off sets, cutter
radius compensation and wear compensation
5. Common Problems in CNC Machines
Common problems in mechanical, electrical, pneumatic, electronic and PC
components of CNC machines, diagnostic study of common problems and
remedies, use of on-time fault finding diagnosis tools in CNC machines
6. Other Automation Equipment
CNC turning centres, CNC vertical and horizontal machining centre, CAM,
introduction to flexible manufacturing system (FMS) and robotics
LIST OF PRACTICALS
1. Study the constructional details of CNC lathe.
2. Study the constructional details and working of following:-
- Automatic tool changer and tool setter
- Multiple pallets
- Swarf removal system
- Safety devices
3. Develop a part programme for following lathe operations:
- Plain turning and facing operations
- Taper turning operations (internal and external)
- Thread cutting operations (internal and external)
4. Preparation of preventive maintenance schedule for CNC machine.
INSTRUCTIONAL STRATEGY
This is a highly practice-based course. Efforts should be made to develop programming
skills amongst the students. During practice work, it should be ensured that students get
opportunity to individually perform practical tasks.
RECOMMENDED BOOKS
1. CNC Machines –Programming and Applications by M Adithan and BS Pabla,
New Age International (P) Ltd., Delhi.
2. Computer Aided Manufacturing by Rao, Kundra and Tiwari; Tata McGraw Hill,
New Delhi.
3. Numerical Control of Machines Tools by Yorem Korem and IB Uri, Khanna
Publishers, New Delhi.
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 4 8
2. 6 14
3. 10 20
4. 16 30
5. 6 14
6. 6 14
Total 48 100
GENERIC SKILL DEVELOPMENT CAMP – I
As per general feedback received from the employers regarding Technician Engineers during
formal interactions, the pass outs of polytechnics are labeled of falling short of employable
skills which comprises of Communication, inter-personal relationship, leadership qualities,
team work, problem solving, managing task, managing self etc. in addition to technical
knowledge and skills. We have, therefore, added papers such as English and Communication
Skills and Entrepreneurship Development and Management in the curriculum in addition to
proposed camps of 3-4 days to be conducted in polytechnics on common and vital issues e.g.
Environmental Awareness, Entrepreneurship Development and Generic Skill Development.
It is proposed that a camp of 3-4 days duration on Generic Skills Development (GSD) during
5th semester be organized by arranging expert lectures/discussion sessions either by polytechnic
teachers or by eminent educationists from the neighborhood to deal with the following topics.
Few students may also be encouraged to prepare on some of these topics and make presentation
during the camp. Expert lectures must be followed by distribution of relevant handouts for
further study. The attendance of students should be compulsory and marks be awarded under
provision of Student Centred Activities.
It is envisaged that such camps will bring in a significant improvement in confidence level and
personality of the pass outs from polytechnics.
Suggested list of topics for arranging lectures/discussion sessions:
1. Independent Study Technique
1.1 Information search, information extraction, storage and retrieval
1.2 Reading skills
1.3 Life long learning
1.4 Continuing education
2. 2.1 Introduction
2.2 Time Management
2.3 Stress and emotions
2.4 Health and hygiene
3. Task Management
3.1 Task planning and organizing
3.2 Task execution
3.3 Task evaluation
3.4 Event management
4. Action Research
4.1 Importance and Scope
4.2 Steps in action research
4.3 Analysis of data
4.4 Conclusions and report writing
RATIONALE
Diploma holder in Mechanical Engineering comes across many machines. He must have
the knowledge of various mechanisms, power transmission devices, balancing of masses,
vibrations etc. Hence this subject is offered.
DETAILED CONTENTS
1. Basic Concepts
1.1 Definition of statics, kinetics, kinematics and dynamics.
1.2 Rigid body and resistant body.
1.3 Links.
1.4 Kinematics pairs and their types.
1.5 Degree of freedom.
1.6 Kinematics chain and their types.
1.7 Constrained motion and mechanisms.
1.8 Classification of mechanisms.
1.9 Equivalent mechanism.
1.10 Laws of inversion of mechanisms.
1.11 Single slider crank chain and its inversions.
1.12 Quick return mechanism and IC engine mechanism.
1.13 Double slider crank chain mechanism and its inversions like scotch yoke
mechanism.
1.14 Applications of mechanisms and their selection from manufacture
catalogue.
1.15 Indicator mechanism, pantograph.
1.16 Steering gear mechanism.
2. Fly Wheel
2.1 Functions of fly wheel.
2.2 Types of fly wheels.
2.3 Mass and size calculations in different cases
3. Governors
3.1 Functions of governor
3.2 Types of governor - elementary knowledge of porter governor, watt
governor, proell governor, Hartnell governor, spring controlled gravity
governor
3.3 Hunting, isochronism, stability, sensitiveness of a governor
3.4 Simple problems related to watt, porter and proell governor
4. Cams
4.1 Definition of cam
4.2 Classification of cams
4.3 Followers and their classification
4.4 Brief description of different types of cams and followers with simple line
diagram
4.5 Simple cam profile for uniform velocity, SHM and uniform acceleration
and deceleration
5. Power Transmission Devices (Belt, Rope and Chain Drive)
5.1 Introduction.
5.2 Belt and rope drives, open and crossed belt drives, action of belt on
pulleys, velocity ratio.
5.3 Material for belts and ropes.
5.4 Slip in belts, ropes, and chains.
5.5 Types of V Belt and Flat belt, joint preparation for flat belt.
5.6 Types of pulleys - step pulley, flat pulley, jockey pulley.
5.7 Crowning in pulley.
5.8 Laws of belting and length of belt
5.9 Ratio of tensions
5.10 Power transmitted and maximum power transmitted by belt
5.11 Centrifugal effect on belt
5.12 Initial tension, creep
5.13 Chain drive, chain length, classification of chains
5.14 Selection of belt, chain and pulley for different applications on the basis of
centre distance between the shaft, power to be transmitted, availability of
space, slip, velocity ratio
5.15 Selection of rope based on the load to be lifted
5.16 Simple problems on power transmitted by belts and ropes
6. Gear Drive
6.1 Functions of gear
6.2 Classification of gears
6.3 Gear nomenclature
6.4 Simple, compound, reverted and epicyclic
6.5 Horsepower transmitted by a gear train
6.6 Selection of gear trains- simple and epicyclic
7. Brakes and Dynamometers
7.1 Introduction
7.2 Brief description of different types of brake such as block or shoe brake,
band brake, internal expanding,power brake and disc brake
7.3 Simple problems related to shoe brake and band brake
7.4 Definition and types of dynamometers, pony brake dynamometer, rope
brake dynamometers, hydraulic dynamometer, belt transmission
dynamometer and Bevis Gibson torsion dynamometer
8. Clutches
8.1 Function of clutch
8.2 Classification of clutches
8.3 Principle of working of single plate clutch and cone clutch with simple line
diagram
8.4 Multi plate clutch
8.5 Calculation of frictional torque for uniform pressure and uniform wear
8.6 Horse power transmitted
8.7 Selection of clutches for different applications from hand book/catalogue
9. Balancing
9.1 Need of balancing
9.2 Concept of static and dynamic balancing
9.3 Balancing of rotating mass by another mass in the same plane
9.4 Forces due to revolving masses
9.5 Concept of reference plane
9.6 Balancing of several masses rotating in same plane
9.7 Balancing of several masses rotating in different planes
10. Vibrations
10.1 Introduction
10.2 Types of vibration - longitudinal, transverse and torsional vibration
10.3 Damping of vibrations
INSTRUCTIONAL STRATEGY
1. Use teaching aids for classroom teaching.
2. Give assignments for solving numerical problems.
3. Arrange industry visits to augment explaining use of various machine components
like belt, rope, chain, gear drives, action due to unbalanced masses, brake clutch,
governors, fly wheels, cams and gear drives.
4. Video films may be used to explain the working of mechanisms and machine
components like clutch, governors, brake etc.
RECOMMENDED BOOKS
1. Mechanism and Machine Theory; JS Rao and Dukkipati; Wiley Eastern, New
Delhi.
2. Theory of Mechanism and Machine; A Ghosh and AK Malik, East West Press
(Pvt.) Ltd., New Delhi.
3. Theory of Machines; SS Rattan: Tata McGraw Hill, New Delhi.
.
4. Theory of Machines by RS Khurmi and JK Gupta; S.Chand and Company Ltd.,
New Delhi.
5. Theory of Machines and Mechanisms by PL Ballaney; Khanna Publishers, New
Delhi.
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 6 10
2. 8 12
3. 8 12
4. 8 12
5. 8 12
6. 8 12
7. 4 6
8. 4 6
9. 8 12
10. 2 6
Total 64 100
METROLOGY
L T P
3 - 2
RATIONALE
Diploma holders in these courses are required to measure and inspect for ensuring quality
of product. For this purpose, knowledge and skills about standards of measurement, limit,
fits and tolerances, types of inspection and various measuring instruments are required.
Hence this subject is offered
DETAILED CONTENTS
1. Introduction
1.1 Definition of metrology
1.2 Standard of measurement
1.3 Types of errors- Controllable and random errors
1.4 Precision, accuracy, sensitivity, hysterisis, response time, repeatability,
calibration, uncertainty of measurement
2. Linear Measurement
2.1 Construction features and use of instruments for non precision linear
measurement: steel rule, callipers, surface plate, angle plate, V-block.
2.2 Construction features and use of instruments for precision measurements :
vernier calipers, vernier height and depth gauges, micrometers.
2.3 Slip gauges, Indian standards of slip gauges, sets of slip gauges, use of slip
gauges.
2.4 Cylinder bore gauges, feeler and wire gauges.
2.5 Comparators – Characteristics, uses, working principles of different types
of comparators: mechanical, electrical, electronics and pneumatic
comparator.
3. Angular Measurement
3.1 Construction and use of instruments for angular measurements: bevel
protector, sine bar, angle gauges, clinometer.
3.2 Optical instruments for angular measurement, auto collimator.
4. Measurement of Surface Finish
4.1 Terminology of surface roughness.
4.2 Concept of primary texture and secondary texture.
4.3 Factors affecting surface finish.
4.4 CLA, RMS and RA value.
4.5 Principle and operation of stylus probe instruments for measuring surface
roughness
5. Measurements of Screw threads and Gears
5.1 Measurement of screw threads- Introduction, measurements of external
and core diameters, checking of pitch and angle of threads with gauges.
5.2 Effective diameter measurement by three wire method.
5.3 Measurements of gears (spur) – Measurement of tooth thickness, pitch,
testing of alignment of teeth.
5.4 Profile projector, Coordinate Measuring Machine (CMM), Tool maker’s
microscope.
6. Machine Tool Testing
6.1 Alignment test on lathe, drilling machine and milling machine.
7. Limits, Fits and Tolerances
7.1 Definition and terminology of limits, fits and tolerances.
7.2 Hole basis and shaft basis systems.
7.3 Type of fits.
7.4 Limit gauges.
8. Instrumentation
Brief description about the measurement of displacement, vibration, frequency,
pressure, temperature and humidity by electromechanical transducers
LIST OF PRACTICALS
1. Internal and external measurement with vernier caliper and micrometer.
2. Measurement with height gauge and depth gauge.
3. Measurement of flatness with dial indicator.
4. Measurement with combination set and bevel protector.
5. Study and use of slip gauges.
6. Measurement of gear characteristics
7. Measurement of angle with sine bar and slip gauges
8. Measurement of worn out IC engine piston clearance between cylinder and piston.
9. Measurement of flatness using comparator.
10. Determination of temperature by (i) pyrometer (ii) thermocouple.
11. Use of feeler gauge, wire gauge , radius gauge and fillet gauges for checking of
standard parameters.
12. Measurement of surface roughness of a surface
INSTRUCTIONAL STRATEGY
1. Demonstrate use of various measuring instruments while imparting theoretical
instructions.
2. Stress should be laid on correct use of various instruments.
RECOMMENDED BOOKS
1. Engineering Metrology by RK Jain; Khanna Publishers, New Delhi.
2. A Text Book of Production Engineering by PC Sharma; S Chand and Company,
New Delhi.
3. Metrology Laboratory Manual by M Adithan and R Bahl; NITTTR, Chandigarh.
4. Engineering Metrology by RK Rajput; SK Kataria and Sons, Ludhiana.
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 4 10
2. 8 18
3. 7 14
4. 6 12
5. 6 12
6. 6 12
7. 5 10
8. 6 12
Total 48 100
PRODUCTION TECHNOLOGY- I
L T P
3 - 6
RATIONALE
This subject provides knowledge and develops skills on various machine operations viz
capstan and turret Lathe, milling, grinding, gear manufacturing, broaching and automatic
machines which is very essential for Mechanical diploma holders to work in
manufacturing industries
DETAILED CONTENTS
1. Capstan and Turret Lathe
1.1 Concept of capstan and turret lathe
1.2 Principal parts of capstan and turret lathe
1.3 Turret indexing mechanism, Bar feeding mechanism
1.4 Work holding devices – Jaw and collet chucks
1.5 Tool holding devices – Slide tool holder, Knee tool holder, knurling tool
holder, recessing tool holder, form tool holder, tap and die holder, Vsteady
box tool holder, roller steady, box tool holder, bar stops.
1.6 Introduction to turret tooling layout
1.7 Comparison of capstan, turret and conventional lathe.
2. Milling
2.1 Specification and working principle of milling machine
2.2 Classification, brief description and applications of milling machines
2.3 Details of column and knee type milling machine
2.4 Milling machine accessories and attachment – Arbors, adaptors, collets,
vices, circular table, indexing head and tail stock, vertical milling
attachment, spiral milling attachment, slotting attachment and rack milling
attachment.
2.5 Milling methods - up milling and down milling
2.6 Identification of different milling cutters and work mandrels
2.7 Work holding devices
2.8 Milling operations – face milling, angular milling, form milling, straddle
milling and gang milling.
2.9 Cutting speed and feed, simple numerical problems.
2.10 Indexing on dividing heads, plain and universal dividing heads.
3. Grinding
3.1 Purpose of grinding
3.2 Various elements of grinding wheel – Abrasive, Grade, structure, Bond
3.3 Common wheel shapes and types of wheel – built up wheels, mounted
wheels and diamond wheels. Specification of grinding wheels as per BIS.
3.4 Truing, dressing, balancing and mounting of wheel.
3.5 Grinding methods – Surface grinding, cylindrical grinding and centreless
grinding.
3.6 Grinding machine – Cylindrical grinder, surface grinder, internal grinder,
centreless grinder, tool and cutter grinder.
3.7 Selection of grinding wheel
4. Gear Manufacturing Processes
4.1 Gear hobbing
4.2 Gear shaping
5. Broaching
5.1 Introduction
5.2 Types of broaching machines – Single ram and duplex ram horizontal type,
vertical type pull up, pull down, push down.
5.3 Elements of broach tool, broach teeth details – nomenclature, types, tool
material.
PRACTICAL EXERCISES
1. Exercise on Turrent/ Capstan Lathe to prepare a job of given dimensions
2. To produce a rectangular block by face milling and prepare a slot on one face.
3. Exercise on milling- slab milling, Gang milling and straddle milling
4. To produce a gear by indexing device on a milling machine
5. Preparing job on following machines:-
a) Surface grinder
b) Cylindrical grinder
6. Exercise on tool and cutter Grinder
a) To grind Lathe tools
b) To grind a drill bit
c) To grind a milling cutter
INSTRUCTIONAL STRATEGY
1. Teaches should lay special emphasis in making the students conversant with
concept, principle, procedure and practices related to various manufacturing
processes
2. Focus should be laid on preparing jobs using various machines/ equipment in
the workshop
3. Aids/ Video films should be used to show operations
RECOMMENDED BOOKS
1. Manufacturing technology by Rao; Tata McGraw hill Publishers, New Delhi
2. Manufacturing technology by M. Adithan and AB. Gupta; New Age International
(P) Ltd, New Delhi
3. Workshop Technology vol I, II, III by Champman; Standard publishers
Distributors
4. Practical hand book for Mechanical Engineers by AB Gupta; Galgotia
publications, New Delhi
5. Production technology by HMT, Tata McGraw Publishers; New Delhi
6. Principle of metal cutting by Bhattacharya, Standard publishers Distributors,
New Delhi
7. Fundamentals of metal cutting and machine tools by Juneja and Sekhon; Wiley
Eastern Ltd., New Delhi
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 12 28
2. 12 28
3. 8 12
4. 10 20
5. 6 12
Total 48 100
COMPUTER AIDED DRAFTING
L T P
- - 6
1. Introduction to AutoCAD commands
1.1 Concept of AutoCAD, Tool bars in Auto CAD, coordinate system, snap,
grid, and ortho mode
1.2 Drawing commands – point, line, arc, circle, ellipse,
1.3 Editing commands – scale, erase, copy, stretch, lengthen and explode.
1.4 Dimensioning and placing text in drawing area
1.5 Sectioning and hatching
1.6 Inquiry for different parameters of drawing entity
2. Assembly and detail drawings of the following using AUTOCAD (9 sheets)
2.1 Tool post
2.2 Tail stock
2.3 Screw jack
2.4 Safety valve
2.5 Stuffing Box
2.6 Bench vice
3. Isometric Drawings by CAD
Drawings of following on computer:
- Cone
- Cylinder
- Isometric view of objects
4. 3D Modelling
3D modelling, Transformations, scaling, rotation, translation
INSTRUCTIONAL STRATEGY
1. Teachers should show model or realia of the component/part whose drawing is to be
made.
2. Emphasis should be given on cleanliness, dimensioning, layout of sheet.
3. Teachers should ensure use of IS codes related to drawing.
RECOMMENDED BOOKS
1. AutoCAD 2000 for you by Umesh Shettigar and Abdul Khader; Janatha
Publishers, Udupi.
2. Machine Drawing by P.S. Gill; Kataria and Sons, Ludhiana.
3. A Text book of Machine Drawing by R.K. Dhawan , S.Chand and Company Ltd.,
New Delhi.
4. Engineering Drawing with AutoCAD 2000 by T. Jeyapooran; Vikas Publishing
House, Delhi.
5. AutoCAD for Engineering Drawing Made Easy by P. Nageswara Rao; Tata
McGraw Hill, New Delhi.
MACHINE DESIGN
L T P
4 - -
RATIONALE
The contents of this subject are organised to understand the intricacies of different
engineering design aspects. This will also help the students to enhance their imagination,
innovative skill, adaptability to new situation and continued learning skills for problem
solving.
DETAILED CONTENTS
1. Introduction
1.1 Design – Definition, Type of design, necessity of design
1.1.1 Comparison of designed and undesigned work
1.1.2 Design procedure
1.1.3 Practical examples related with design procedure
1.1.4 Characteristics of a good designer
1.1.5 Characteristics of environment required for a designer
1.2 Design terminology: stress, strain, factor of safety, factors affecting factor
of safety, stress concentration, methods to reduce stress concentration,
fatigue, endurance limit. General design considerations
1.3 Engineering materials and their mechanical properties :
1.3.1 Properties of engineering materials: elasticity, plasticity,
malleability, ductility, toughness, hardness and resilience. Fatigue,
creep, tenacity, strength
1.3.2 Selection of materials, criterion of material selection
2. Design Failure
2.1 Various design failures
- Maximum principal stress theory.
- Maximum shear stress theory
- Maximum strain theory
2.2 Design for tensile, compressive and torsional loading
2.3 Design for combined torsion and bending
3. Design of Shaft
3.1 Type of shaft, shaft materials, Type of loading on shaft, standard sizes of
shaft available
3.2 Shaft subjected to torsion only, determination of shaft diameter on the
basis of :
- Strength criterion
- Rigidity criterion
3.3 Shaft subjected to bending
3.4 Shaft subjected to combined torsion and bending
4. Design of Key
4.1 Types of key, materials of key, functions of key
4.2 Failure of key (by Shearing and Crushing).
4.3 Design of key (Determination of key dimension)
4.4 Effect of keyway on shaft strength. (Figures and problems).
5. Design of Joints
Types of joints - Temporary and Permanent, utility of joints
5.1 Temporary Joint:
5.1.1 Knuckle Joints – Different parts of the joint, material used for the
joint, type of knuckle Joint, design of the knuckle joint. (Figures
and problems).
5.1.2 Cotter Joint – Different parts of the joint, type of cotter joint –
spigot and socket joint, gib and cotter joint, sleeve and cotter joint,
Design of cotter joint (Figures and problems).
5.2 Permanent Joint:
Welding symbols, standards and materials having high weldability.
5.2.1 Welded Joint - Type of welded joint, strength of parallel and
transverse fillet welds.
5.2.2 Strength of combined parallel and transverse weld.
5.2.3 Axially loaded welded joints.
5.2.4 Riveted Joints. : Rivet materials, Rivet heads, leak proofing of
riveted joint – caulking and fullering.
5.2.5 Different modes of rivet joint failure.
5.2.6 Design of riveted joint – Lap and butt, single and multi riveted
joint, Diamond (Lozenzo) joint, circumferential and longitudinal
boiler joints
6. Design of Flange Coupling
Necessity of a coupling, advantages of a coupling, types of couplings, design of
flange coupling. (both protected type and unprotected type).
7. Design of Pulley
7.1 Types of pulley, crowning of pulley, pulley materials, components of a
pulley.
7.2 Determination of pulley dimensions (Figures and problems).
8. Design of Screw, Nut, Bolt and Thread
8.1 Form of thread (ISO), Type of nut heads, type of threads and their
nomenclature.
8.2 Nature of loads on nut and bolts, types of failure of nut and bolts.
8.3. Initial stresses due to screwing up, stresses due to combination of different
loads.
.
INSTRUCTIONAL STREATEGY
1. Use models of machine parts/components.
2. Presentation should be arranged for various topics.
REFERENCE BOOKS
1. Machine Design by R.S. Khurmi and JK Gupta; Eurasia Publishing House (Pvt.)
Limited, New Delhi.
2. Machine Design by V.B.Bhandari; Tata McGraw Hill, New Delhi.
3. Machine design by R.A Agarwal; Nav Bharat parkashan, Meerut.
4. Machine Design by Sharma and Agrawal; Katson Publishing House, Ludhiana.
5. Machine design by J.K. Kapoor, B. Bharat Parkashan, Meerut.
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 6 10
2. 3 5
3. 14 22
4. 4 6
5. 20 30
6. 6 10
7. 3 5
8. 8 12
Total 64 100
CNC MACHINES AND AUTOMATION
L T P
3 - 4
RATIONALE
Students are required to supervise and handle specialized machines and equipments like
CNC machines. This subject aims at development of knowledge and skill about CNC
machines tools, equipment and use of high tech. machines
DETAILED CONTENTS
1. Automation
1.1 Definition
1.2 Types of Automation
1.3 Need of Automation
1.4 Advantages of Automation
2. Introduction to Numerical Control
Computer applications in manufacturing, basic concepts of NC, CNC, DNC and
adaptive control, advantages and application of CNC machines in industry
3. Components of CNC System
Machine control unit, NC control and PLC control system, introduction to C axis
and special constructional requirements of CNC machines, machine bed, slide
ways, bolt, screw and nut assembly, lubrication and cooling system, spindle and
spindle motors, axis drive motors, automatic tool changers, multiple pallets, swarf
removal mechanisms and safety provision
4. Part Programming
Part programming and basic concepts of part programming, NC words, part
programming formats, simple programming for rotational components, part
programming using canned cycles, subroutines and do loops, tool off sets, cutter
radius compensation and wear compensation
5. Common Problems in CNC Machines
Common problems in mechanical, electrical, pneumatic, electronic and PC
components of CNC machines, diagnostic study of common problems and
remedies, use of on-time fault finding diagnosis tools in CNC machines
6. Other Automation Equipment
CNC turning centres, CNC vertical and horizontal machining centre, CAM,
introduction to flexible manufacturing system (FMS) and robotics
LIST OF PRACTICALS
1. Study the constructional details of CNC lathe.
2. Study the constructional details and working of following:-
- Automatic tool changer and tool setter
- Multiple pallets
- Swarf removal system
- Safety devices
3. Develop a part programme for following lathe operations:
- Plain turning and facing operations
- Taper turning operations (internal and external)
- Thread cutting operations (internal and external)
4. Preparation of preventive maintenance schedule for CNC machine.
INSTRUCTIONAL STRATEGY
This is a highly practice-based course. Efforts should be made to develop programming
skills amongst the students. During practice work, it should be ensured that students get
opportunity to individually perform practical tasks.
RECOMMENDED BOOKS
1. CNC Machines –Programming and Applications by M Adithan and BS Pabla,
New Age International (P) Ltd., Delhi.
2. Computer Aided Manufacturing by Rao, Kundra and Tiwari; Tata McGraw Hill,
New Delhi.
3. Numerical Control of Machines Tools by Yorem Korem and IB Uri, Khanna
Publishers, New Delhi.
SUGGESTED DISTRIBUTION OF MARKS
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1. 4 8
2. 6 14
3. 10 20
4. 16 30
5. 6 14
6. 6 14
Total 48 100
GENERIC SKILL DEVELOPMENT CAMP – I
As per general feedback received from the employers regarding Technician Engineers during
formal interactions, the pass outs of polytechnics are labeled of falling short of employable
skills which comprises of Communication, inter-personal relationship, leadership qualities,
team work, problem solving, managing task, managing self etc. in addition to technical
knowledge and skills. We have, therefore, added papers such as English and Communication
Skills and Entrepreneurship Development and Management in the curriculum in addition to
proposed camps of 3-4 days to be conducted in polytechnics on common and vital issues e.g.
Environmental Awareness, Entrepreneurship Development and Generic Skill Development.
It is proposed that a camp of 3-4 days duration on Generic Skills Development (GSD) during
5th semester be organized by arranging expert lectures/discussion sessions either by polytechnic
teachers or by eminent educationists from the neighborhood to deal with the following topics.
Few students may also be encouraged to prepare on some of these topics and make presentation
during the camp. Expert lectures must be followed by distribution of relevant handouts for
further study. The attendance of students should be compulsory and marks be awarded under
provision of Student Centred Activities.
It is envisaged that such camps will bring in a significant improvement in confidence level and
personality of the pass outs from polytechnics.
Suggested list of topics for arranging lectures/discussion sessions:
1. Independent Study Technique
1.1 Information search, information extraction, storage and retrieval
1.2 Reading skills
1.3 Life long learning
1.4 Continuing education
2. 2.1 Introduction
2.2 Time Management
2.3 Stress and emotions
2.4 Health and hygiene
3. Task Management
3.1 Task planning and organizing
3.2 Task execution
3.3 Task evaluation
3.4 Event management
4. Action Research
4.1 Importance and Scope
4.2 Steps in action research
4.3 Analysis of data
4.4 Conclusions and report writing
Saturday, 13 October 2012
About Mechanical energy
Mechanical Energy
In
a previous part of Lesson 1, it was
said that work is done upon an object whenever a force acts
upon it to cause it to be displaced. Work involves a force acting
upon an object to cause a displacement. In all instances in
which work is done, there is an object that supplies the
force in order to do the work. If a World Civilization book
is lifted to the top shelf of a student locker, then the
student supplies the force to do the work on the book. If a
plow is displaced across a field, then some form of farm
equipment (usually a tractor or a horse) supplies the force
to do the work on the plow. If a pitcher winds up and
accelerates a baseball towards home plate, then the pitcher
supplies the force to do the work on the baseball. If a
roller coaster car is displaced from ground level to the top
of the first drop of a roller coaster ride, then a chain
driven by a motor supplies the force to do the work on the
car. If a barbell is displaced from ground level to a height
above a weightlifter's head, then the weightlifter is
supplying a force to do work on the barbell. In all
instances, an object that possesses some form of energy
supplies the force to do the work. In the instances
described here, the objects doing the work (a student, a
tractor, a pitcher, a motor/chain) possess chemical
potential energy stored in food or fuel that is
transformed into work. In the process of doing work, the
object that is doing the work exchanges energy with the
object upon which the work is done. When the work is done
upon the object, that object gains energy. The energy
acquired by the objects upon which work is done is known as
mechanical energy.Mechanical Energy as the Ability to Do Work
An
object that possesses mechanical energy is able to do work.
In fact, mechanical energy is often defined as the ability
to do work. Any object that possesses mechanical energy -
whether it is in the form of potential
energy or kinetic energy - is
able to do work. That is, its mechanical energy enables that
object to apply a force to another object in order to cause
it to be displaced.Numerous examples can be given of how an object with mechanical energy can harness that energy in order to apply a force to cause another object to be displaced. A classic example involves the massive wrecking ball of a demolition machine. The wrecking ball is a massive object that is swung backwards to a high position and allowed to swing forward into building structure or other object in order to demolish it. Upon hitting the structure, the wrecking ball applies a force to it in order to cause the wall of the structure to be displaced. The diagram below depicts the process by which the mechanical energy of a wrecking ball can be used to do work.
A
hammer is a tool that utilizes mechanical energy to do
work. The mechanical energy of a hammer gives the hammer its
ability to apply a force to a nail in order to cause it to
be displaced. Because the hammer has mechanical energy (in
the form of kinetic energy), it is
able to do work on the nail. Mechanical energy is the
ability to do work.
Another
example that illustrates how mechanical energy is the
ability of an object to do work can be seen any evening at
your local bowling alley. The mechanical energy of a bowling
ball gives the ball the ability to apply a force to a
bowling pin in order to cause it to be displaced. Because
the massive ball has mechanical energy (in the form of
kinetic energy), it is able to do
work on the pin. Mechanical energy is the ability to do
work.
A
dart gun is still another example of how mechanical energy
of an object can do work on another object. When a dart gun
is loaded and the springs are compressed, it possesses
mechanical energy. The mechanical energy of the compressed
springs gives the springs the ability to apply a force to the
dart in order to cause it to be displaced. Because of the
springs have mechanical energy (in the form of elastic
potential energy), it is able to do
work on the dart. Mechanical energy is the ability to do
work.
A common scene in some parts of the countryside is a "wind farm." High-speed winds are used to do work on the blades of a turbine at the so-called wind farm. The mechanical energy of the moving air gives the air particles the ability to apply a force and cause a displacement of the blades. As the blades spin, their energy is subsequently converted into electrical energy (a non-mechanical form of energy) and supplied to homes and industries in order to run electrical appliances. Because the moving wind has mechanical energy (in the form of kinetic energy), it is able to do work on the blades. Once more, mechanical energy is the ability to do work.
The Total Mechanical Energy
As already mentioned, the mechanical energy of an object can be the result of its motion (i.e., kinetic energy) and/or the result of its stored energy of position (i.e., potential energy). The total amount of mechanical energy is merely the sum of the potential energy and the kinetic energy. This sum is simply referred to as the total mechanical energy (abbreviated TME).
TME = PE +
KE
As discussed earlier, there are two forms of potent discussed in our course - gravitational potential
energy and elastic potential energy. Given this fact, the
above equation can be rewritten:
TME = PEgrav +
PEspring + KE
The diagram below depicts the motion of
Li Ping Phar (esteemed Chinese ski jumper) as she glides
down the hill and makes one of her record-setting jumps.
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