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BOX SHIFTING MECHANISM
By
DEPARTMENT OF MECHANICAL ENGINEERING
DESH BHAGAT FOUNDATION GROUP OF INSTITUTION ( MOGA )
2013/2014
PROJECT REPORT ON
BOX SHIFTING MECHANISM
1
AKNOWLEDGEMENT
Index
Title of project 1
Function of BSM 2
Mechanism 2
Types of mechanism ( 3)
Kinematics pairs ( 3-4)
Lower pairs (4-5)
Higher pairs ( 5)
Planar mechanism (5)
Spherical mechanism (5-6)
Spatial mechanism (6)
Shifting 6
2
Process use to making project 6- 7
Gear 7-8
Spur gear (9-13)
Bevel gear (13-21)
Chain driver 21-22
History of chain driver (22-23)
Use in vehicle ( 23-24)
Bearing 25-26
History of bearing ( 26-29)
Operation of principle of bearing (29-30)
Maintenance and lubrication (30-33)
Operation on lathe machine 33
Lathe machine (33-34)
Turing operation (35-38)
Facing operation (38-39)
Welding 39-41
Arc welding process
Arc (41)
Power supply (41-43)
Process of welding (43-46)
Tools 46-47
Hacksaw (47-48)
Blade (48-49)
File (50)
3
Final project 51
PROJECT REPORT
ON
BOX SHIFTING MECHANISM
4
FUNCATION OF BOX SHIFTING MECHANIS
The main function of box shifting mechanism is to transfer the object from one place to
another with the help of mechanism or machine. this I is called box shifting mechanism
or shifting mechanism.
MECHANISM
A mechanism is a device designed to transform input forces and movement into a
desired set of output forces and movement. Mechanisms generally consist of moving
components such as gear and gears train , belt and chain drives, cam and follower
mechanisms, and linkages as well as friction devices such as brakes and clutches, and
structural components such as the frame, fasteners, bearings, springs, lubricants and seals,
as well as a variety of specialized machine elements such as splines, pins and keys.
5
The German scientist Reuleaxu provides the definition "a machine is a combination of
resistant bodies so arranged that by their means the mechanical forces of nature can be
compelled to do work accompanied by certain determinate motion." In this context, his
use of machine is generally interpreted to mean mechanism.
The combination of force and movement defines power and a mechanism is designed to
manage power in order to achieve a desired set of forces and movement.
A mechanism is usually a piece of a larger process or mechanical system Sometimes an
entire machine may be referred to as a mechanism. Examples are the steering system
a car, or the winding mechanism of a wristwatch . Multiple mechanisms are machines.
Types of mechanism
From the time of Archimedes through the Renaissance, mechanisms were considered to
be constructed from simple machine such as the lever , pulley ,wheel and etc.
and inclined plane. It was Reuleaux who focussed on bodies, called links, and the
connections between these bodies called kinamatic pair, or joints.
In order to use geometry to study the movement a mechanism, its links are modeled
as rigid bodies. This means distances between points in a link are assumed to be
unchanged as the mechanism moves, that is the link does not flex. Thus, the relative
movement between points in two connected links is considered to result from the
kinematic pair that joins them.
Kinematic pairs, or joints, are considered to provide ideal constraints between two links,
such as the constraint of a single point for pure rotation, or the constraint of a line for
6
pure sliding, as well as pure rolling without slipping and point contact with slipping. A
mechanism is modeled as an assembly of rigid links and kinematic pairs.
Kinematic pairs
Reuleaux called the ideal connections between links kinematic pairs. He distinguished
between higher pairs which were said to have line contact between the two links and
lower pairs that have area contact between the links. J. Phillips[4] shows that there are
many ways to construct pairs that do not fit this simple classification.
Lower pair
A lower pair is an ideal joint that constrains contact between a point, line or plane in the
moving body to a corresponding point line or plane in the fixed body. We have the
following cases:
A revolute pair, or hinged joint, requires a line in the moving body to remain co-
linear with a line in the fixed body, and a plane perpendicular to this line in the
moving body maintain contact with a similar perpendicular plane in the fixed body.
This imposes five constraints on the relative movement of the links, which therefore
has one degree of freedom.
7
A prismatic joint, or slider, requires that a line in the moving body remain co-
linear with a line in the fixed body, and a plane parallel to this line in the moving
body maintain contact with a similar parallel plan in the fixed body. This imposes
five constraints on the relative movement of the links, which therefore has one degree
of freedom.
A cylindrical joint requires that a line in the moving body remain co-linear with a
line in the fixed body. It is a combination of a revolute joint and a sliding joint. This
joint has two degrees of freedom.
A spherical joint, or ball joint, requires that a point in the moving body maintain
contact with a point in the fixed body. This joint has three degrees of freedom.
A planar joint requires that a plane in the moving body maintain contact with a
plane in fixed body. This joint has three degrees of freedom.
Higher pairs
Generally, a higher pair is a constraint that requires a curve or surface in the moving
body to maintain contact with a curve or surface in the fixed body. For example, the
contact between a cam and its follower is a higher pair called a cam joint. Similarly, the
contact between the involute curves that form the meshing teeth of two gears are cam
joints.
Planar mechanism
8
A planar mechanism is a mechanical system that is constrained so the trajectories of
points in all the bodies of the system lie on planes parallel to a ground plane. The
rotational axes of hinged joints that connect the bodies in the system are perpendicular to
this ground plane.
Spherical mechanism
A spherical mechanism is a mechanical system in which the bodies move in a way that
the trajectories of points in the system lie on concentric spheres. The rotational axes of
hinged joints that connect the bodies in the system pass through the center of these
spheres.
Spatial mechanism
A spatial mechanism is a mechanical system that has at least one body that moves in a
way that its point trajectories are general space curves. The rotational axes of hinged
joints that connect the bodies in the system form lines in space that that do not intersect
and have distinct common normals.
SHIFTING
9
Shifting is that process in which object is transfer from one place to another place ita
known as shifting.
Combination of both is called shifting mechanism or box shifting mechanism.
The followings process use in making box shifting project as :-
Rods
Metal plates
Gears like bevel gear and spur gear
Chain driver
bearings
Operation on lathe like turning operation and facing operation
Welding
Cutting tools
GEARS
gear or cogwheel is a rotating machine part having cut teeth, or cogs, which mesh with
another toothed part in order to transmit torque, in most cases with teeth on the one gear
10
of identical shape, and often also with that shape (or at least width) on the other gear.
Two or more gears working in tandem are called a transmission and can produce
a mechanical advantage through a gear ratio and thus may be considered a simple
machine. Geared devices can change the speed, torque, and direction of a power source.
The most common situation is for a gear to mesh with another gear; however, a gear can
also mesh with a non-rotating toothed part, called a rack, thereby
producingtranslation instead of rotation.
The gears in a transmission are analogous to the wheels in a crossed belt pulley system.
An advantage of gears is that the teeth of a gear prevent slipping.
When two gears of unequal number of teeth are combined, a mechanical advantage is
produced, with the rotational speeds and the torques of the two gears differing in a simple
inverse relationship.
In transmissions which offer multiple gear ratios, such as bicycles and cars, the term gear,
as infirst gear, refers to a gear ratio rather than an actual physical gear. The term is used
to describe similar devices even when the gear ratio is continuous rather than discrete, or
when the device does not actually contain any gears, as in a continuously variable
transmission
There are some gears images as below
11
SPUR GEAR
Spur gears or straight-cut gears are the simplest type of gear. They consist of a cylinder
or disk with the teeth projecting radially, and although they are not straight-sided in form
(they are usually of special form to achieve constant drive ratio mainly involute), the
edge of each tooth is straight and aligned parallel to the axis of rotation. These gears can
be meshed together correctly only if they are fitted to parallel shafts.
These are spur gears
.
12
Matetrial use to making spur gears
Acetal
Acetal is a plastic polymer that is used either in its pure state or slightly altered
state---e.g. Derlin---for a number of spur gears. The acetal polymer is much stronger than
common plastic, though it can be easily molded to any shape, including a spur gear. Once
acetal has hardened in the shape of a spur gear, it is stif, strong and resistant to abrasion.
The malleability, strength and resilience make it an ideal material for spur gears.
13
Cast Iron
Cast iron is, like acetal, an easily molded material. It is also highly resistant to
rust. Cast iron is not pure iron, and because of this, any given batch of cast iron will have
different ingredients. These different ingredients cohere for different degrees of strength
and durability. Cast iron is used in machine parts because it is relatively inexpensive, rust
resistant and easy to mold, though it may be either incredibly strong or incredibly weak,
depending upon the admixture.
Stainless Steel
Stainless steel is a metal alloy commonly used in the casting of spur gears. A
metal alloy is a metal composed of two or more distinct elements that are melted
together. Like cast iron, it is highly resistant to oxidation, and like acetal, it is resistant to
abrasions and other weakening blemishes. Stainless steel's resistance to rust and scarring
is due to the infusion of chromium. The strength, durability and corrosion resistance
make stainless steel a popular material for spur gears.
14
Application of spur gears
Spur gears have a wide range of applications. They are used in:
1. Metal cutting machines
2. Power plants
3. Marine engines
4. Mechanical clocks and watches
5. Fuel pumps
6. Washing Machines
7. Gear motors and gear pumps
8. Rack and pinion mechanisms
9. Material handling equipments
10. Automobile gear boxes
11. Steel mills
12. Rolling mills
Advantages of spur gears
15
Spur gears have high power transmission efficiency.
They are compact and easy to install.
They offer constant velocity ratio.
Unlike belt drives, spur gear drives have no slip.
Spur gears are highly reliable.
They can be used to transmit large amount of power (of the order of 50,000 kW).
Disadvantages of spur gears
Spur gear drives are costly when compared to belt drives.
They have a limited center distance. This is because in a spur gear drive, the gears
should be meshed and they should be in direct contact with each other.
Spur gears produce a lot of noise when operating at high speeds.
16
They cannot be used for long distance power transmission.
Gear teeth experience a large amount of stress.
Bevel gear
wo important concepts in gearing are pitch surface and pitch angle. The pitch surface of
a gear is the imaginary toothless surface that you would have by averaging out the peaks
and valleys of the individual teeth. The pitch surface of an ordinary gear is the shape of a
cylinder. The pitch angle of a gear is the angle between the face of the pitch surface and
the axis.
The most familiar kinds of bevel gears have pitch angles of less than 90 degrees and
therefore are cone-shaped. This type of bevel gear is called external because the gear
teeth point outward. The pitch surfaces of meshed external bevel gears are coaxial with
the gear shafts; the apexes of the two surfaces are at the point of intersection of the shaft
axes.
Bevel gears that have pitch angles of greater than ninety degrees have teeth that point
inward and are called internal bevel gears.
17
Bevel gears that have pitch angles of exactly 90 degrees have teeth that point outward
parallel with the axis and resemble the points on a crown. That's why this type of bevel
gear is called acrown gear.
Miter gears are mating bevel gears with equal numbers of teeth and with axes at right
angles.
Skew bevel gears are those for which the corresponding crown gear has teeth that are
straight and oblique.
Types of bevel gears
Bevel gears are classified in different types according to geometry:
Straight bevel gears have conical pitch surface and teeth are straight and tapering
towards apex.
Spiral bevel gears
have curved teeth at an angle allowing tooth contact to be gradual and
smooth.
18
Zerol bevel gears
are very similar to a bevel gear only exception is the teeth are curved: the ends of
each tooth are coplanar with the axis, but the middle of each tooth is swept
circumferentially around the gear. Zerol bevel gears can be thought of as spiral bevel
gears (which also have curved teeth) but with a spiral angle of zero (so the ends of the
teeth align with the axis).
Hypoid bevel gears are similar to spiral bevel but the pitch surfaces
are hyperbolic and not conical. Pinion can be offset above, or below,the gear centre,
thus allowing larger pinion diameter, and longer life and smoother mesh, with
additional ratios e.g., 6:1, 8:1, 10:1. In a limiting case of making the "bevel" surface
parallel with the axis of rotation, this configuration resembles a worm drive.
19
(hypoid bevel gear)
Materials used in manufacturing of bevel gears
Materials used in gear manufacturing process
The various materials used for gears include a wide variety of cast irons, non ferrous
material &non – metallic materials the selection of the gear material depends upon: i)
Type of service ii) Peripheral speed iii) Degree of accuracy required iv) Method of
manufacture v) Required dimensions & weight of the drive vi) Allowable stress vii)
Shock resistance viii) Wear resistance.
20
1) Cast iron is popular due to its good wearing properties, excellent machinability & ease
of producing complicated shapes by the casting method. It is suitable where large gears
of complicated shapes are needed.
2) Steel is sufficiently strong & highly resistant to wear by abrasion.
3) Cast steel is used where stress on gear is high & it is difficult to fabricate the gears.
4) Plain carbon steels find application for industrial gears where high toughness
combined with high strength.
5) Alloy steels are used where high tooth strength & low tooth wear are required.
6) Aluminum is used where low inertia of rotating mass is desired.
7) Gears made of non–metallic materials give noiseless operation at high peripheral
speeds.
Bevel gearing
21
Two bevel gears in mesh is known as bevel gearing. In bevel gearing, the pitch cone
angles of the pinion and gear are to be determined from the shaft angle, i.e., the angle
between the intersecting shafts. Figure shows views of a bevel gearing
(bevel gearing)
Application of bevel gears
The bevel gear has many diverse applications such as locomotives, marine applications,
automobiles, printing presses, cooling towers, power plants, steel plants, railway track
inspection machines, etc.
22
For examples, see the following articles on:
Bevel gears are used in differential drives, which can transmit power to two
axles spinning at different speeds, such as those on a cornering automobile.
Bevel gears are used as the main mechanism for a hand drill. As the handle of
the drill is turned in a vertical direction, the bevel gears change the rotation of the
chuck to a horizontal rotation. The bevel gears in a hand drill have the added
advantage of increasing the speed of rotation of the chuck and this makes it possible
to drill a range of materials.
The gears in a bevel gear planer permit minor adjustment during assembly and
allow for some displacement due to deflection under operating loads without
concentrating the load on the end of the tooth.
Spiral bevel gears are important components on rotorcraft drive systems. These
components are required to operate at high speeds, high loads, and for a large number
of load cycles. In this application, spiral bevel gears are used to redirect the shaft
from the horizontal gas turbine engine to the vertical rotor.
Advantages of bevel gears
This gear makes it possible to change the operating angle.
23
Differing of the number of teeth (effectively diameter) on each wheel
allows mechanical advantage to be changed. By increasing or decreasing the ratio of
teeth between the drive and driven wheels one may change the ratio of rotations
between the two, meaning that therotational drive and torque of the second wheel can
be changed in relation to the first, with speed increasing and torque decreasing, or
speed decreasing and torque increasing.
Disadvantages of bevel gears
One wheel of such gear is designed to work with its complementary wheel and no
other.
Must be precisely mounted.
The shafts' bearings must be capable of supporting significant forces.
These are bevel gear
24
Chain driver
hain drive is a way of transmitting mechanical power from one place to another. It is
often used to convey power to the wheels of a vehicle,
particularly bicycles and motorcycles. It is also used in a wide variety of machines
besides vehicles.
Most often, the power is conveyed by a roller chain, known as the drive
chain or transmission chain,[1]passing over a sprocket gear, with the teeth of the gear
meshing with the holes in the links of the chain. The gear is turned, and this pulls the
25
chain putting mechanical force into the system. Another type of drive chain is the Morse
chain, invented by the Morse Chain Company of Ithaca, New York, USA. This has
inverted teeth.
Sometimes the power is output by simply rotating the chain, which can be used to lift or
drag objects. In other situations, a second gear is placed and the power is recovered by
attaching shafts or hubs to this gear. Though drive chains are often simple oval loops,
they can also go around corners by placing more than two gears along the chain; gears
that do not put power into the system or transmit it out are generally known as idler-
wheels. By varying the diameter of the input and output gears with respect to each other,
the gear ratiocan be altered, so that, for example, the pedals of a bicycle can spin all the
way around more than once for every rotation of the gear that drives the wheels.
History of chain driver
The oldest known application of a chain drive appears in the Polybolos,
a repeating crossbow described by theGreek engineer Philon of Byzantium (3rd century
BC). Two flat-linked chains were connected to a windlass, which by winding back and
forth would automatically fire the machine's arrows until its magazine was empty.
[3]Although the device did not transmit power continuously since the chains "did not
transmit power from shaft to shaft",[4] the Greek design marks the beginning of the history
of the chain drive since "no earlier instance of such a cam is known, and none as complex
26
is known until the 16th century. It is here that the flat-link chain, often attributed
to Leonardo da Vinci, actually made its first appearance."[3]
The first continuous power-transmitting chain drive was depicted in the
written horological treatise of the Song Dynasty (960–1279) Chinese engineer Su
Song (1020-1101 AD), who used it to operate the armillary sphere of
his astronomical clock tower as well as the clock jack figurines presenting the time of day
by mechanically banging gongs and drums.[5] The chain drive itself was given power via
the hydraulic works of Su's water clock tank and waterwheel, the latter which acted as a
large gear.
Use in the vehicles
Bicycles
Main article: Bicycle chain
Chain drive was the main feature which differentiated the safety bicycle introduced in
1885, with its two equal-sized wheels, from thedirect-drive penny-farthing or "high
wheeler" type of bicycle. The popularity of the chain-driven safety bicycle brought about
the demise of the penny-farthing, and is still a basic feature of bicycle design today.
Automobiles
27
Transmitting power to the wheels
Chain drive was a popular power transmission system from the earliest days of
theautomobile. It gained prominence as an alternative to the Système Panhard with its
rigidHotchkiss driveshaft and universal joints.
A chain-drive system uses one or more roller chains to transmit power from
a differential to the rear axle. This system allowed for a great deal of vertical axle
movement (for example, over bumps), and was simpler to design and build than a rigid
driveshaft in a workable suspension. Also, it had less unsprung weight at the rear wheels
than the Hotchkiss drive, which would have had the weight of the driveshaft and
differential to carry as well. This meant that the vehicle would have a smoother ride. The
lighter unsprung mass would allow the suspension to react to bumps more effectively.
Breaing
28
A bearing is a machine element that constrains relative motion between moving parts to
only the desired motion. The design of the bearing may, for example, provide for
free linearmovement of
ball bearing
the moving part or for free rotation around a fixed axis; or, it may prevent a motion by
controlling the vectors of normal forces that bear on the moving parts. Many bearings
also facilitate the desired motion as much as possible, such as by minimizing friction.
Bearings are classified broadly according to the type of operation, the motions allowed,
or to the directions of the loads (forces) applied to the parts.
29
The term "bearing" is derived from the verb "to bear";[1] a bearing being a machine
element that allows one part to bear (i.e., to support) another. The simplest bearings
are bearing surfaces, cut or formed into a part, with varying degrees of control over the
form, size,roughness and location of the surface. Other bearings are separate devices
installed into a machine or machine part. The most sophisticated bearings for the most
demanding applications are very precise devices; their manufacture requires some of the
highest standards of current technology.
History of bearing
The invention of the rolling bearing, in the form of wooden rollers supporting, or bearing,
an object being moved is of great antiquity, and may predate the invention of the wheel.
Though it is often claimed that the Egyptians used roller bearings in the form of tree
trunks under sleds,[2] this is modern speculation.[3] They are depicted in their own
drawings in the tomb of Djehutihotep as moving massive stone blocks on sledges with
the runners lubricated with a liquid which would constitute a plain bearing. There are also
Egyptian drawings of bearings used withhand drills.
The earliest recovered example of a rolling element bearing is a wooden ball
bearingsupporting a rotating table from the remains of the Roman Nemi ships in Lake
Nemi, Italy. The wrecks were dated to 40 AD.
30
Leonardo da Vinci incorporated drawings of ball bearings in his design for a helicopter
around the year 1500. This is the first recorded use of bearings in an aerospace design.
However, Agostino Ramelli is the first to have published sketches of roller and thrust
bearings.[2] An issue with ball and roller bearings is that the balls or rollers rub against
each other causing additional friction which can be prevented by enclosing the balls or
rollers in a cage. The captured, or caged, ball bearing was originally described
by Galileo in the 17th century. The mounting of bearings into a set was not accomplished
for many years after that. The first patent for a ball race was by Philip
Vaughan of Carmarthen in 1794.
Bearings saw use for holding wheel and axles. The bearings used there were plain
bearings that were used to greatly reduce friction over that of dragging an object by
making the friction act over a shorter distance as the wheel turned.
The first plain and rolling-element bearings were wood closely followed by bronze. Over
their history bearings have been made of many materials
including ceramic, sapphire, glass, steel, bronze, other metals and plastic
(e.g., nylon, polyoxymethylene,polytetrafluoroethylene, and UHMWPE) which are all
used today.
Watch makers produce "jeweled" watches using sapphire plain bearings to reduce friction
thus allowing more precise time keeping.
Even basic materials can have good durability. As examples, wooden bearings can still be
seen today in old clocks or in water mills where the water provides cooling and
lubrication.
31
The first practical caged-roller bearing was invented in the mid-1740s by horologist John
Harrison for his H3 marine timekeeper. This uses the bearing for a very limited
oscillating motion but Harrison also used a similar bearing in a truly rotary application in
a contemporaneous regulator clock.
A patent on ball bearings, reportedly the first, was awarded to Jules Suriray, a Parisian
bicycle mechanic, on 3 August 1869. The bearings were then fitted to the winning bicycle
ridden by James Moore in the world's first bicycle road race, Paris-Rouen, in November
1869.[8]
In 1883, Friedrich Fischer, founder of FAG, developed an approach for milling and
grinding balls of equal size and exact roundness by means of a suitable production
machine and formed the foundation for creation of an independent bearing industry.
The modern, self-aligning design of ball bearing is attributed to Sven Wingquist of
the SKFball-bearing manufacturer in 1907, when he was awarded Swedish patent No.
25406 on its design.
Henry Timken, a 19th-century visionary and innovator in carriage manufacturing,
patented the tapered roller bearing in 1898. The following year he formed a company to
produce his innovation. Over a century the company grew to make bearings of all types,
including specialty steel and an array of related products and services.
Erich Franke invented and patented the wire race bearing in 1934. His focus was on a
bearing design with a cross section as small as possible and which could be integrated
into the enclosing design. After World War II he founded together with Gerhard
32
Heydrich the company Franke & Heydrich KG (today Franke GmbH) to push the
development and production of wire race bearings.
Richard Stribeck’s extensive research on ball bearing steels identified the metallurgy of
the commonly used 100Cr6 showing coefficient of friction as a function of pressure.
Designed in 1968 and later patented in 1972, Bishop-Wisecarver's co-founder Bud
Wisecarver created vee groove bearing guide wheels, a type of linear motion bearing
consisting of both an external and internal 90-degree vee angle.
In the early 1980s, Pacific Bearing's founder, Robert Schroeder, invented the first bi-
material plain bearing which was size interchangeable with linear ball bearings. This
bearing had a metal shell (aluminum, steel or stainless steel) and a layer of Teflon-based
material connected by a thin adhesive layer.
Today ball and roller bearings are used in many applications which include a rotating
component. Examples include ultra high speed bearings in dental drills, aerospace
bearings in the Mars Rover, gearbox and wheel bearings on automobiles, flexure bearings
in optical alignment systems and bicycle wheel hubs.
Principle of operation of bearing
There are at least 6 common principles of operation:
plain bearing , also known by the specific styles: bushing, journal bearing, sleeve
bearing, rifle bearing
33
rolling-element bearing such as ball bearings and roller bearings
jewel bearing , in which the load is carried by rolling the axle slightly off-center
fluid bearing , in which the load is carried by a gas or liquid
magnetic bearing , in which the load is carried by a magnetic field
flexure bearing , in which the motion is supported by a load element which bends.
Maintenance and lubrication of bearings
Many bearings require periodic maintenance to prevent premature failure, but many
others require little maintenance. The latter include various kinds of fluid and magnetic
bearings, as well as rolling-element bearings that are described with terms
including sealed bearingand sealed for life. These contain seals to keep the dirt out and
the grease in. They work successfully in many applications, providing maintenance-free
operation. Some applications cannot use them effectively.
Nonsealed bearings often have a grease fitting, for periodic lubrication with a grease gun,
or an oil cup for periodic filling with oil. Before the 1970s, sealed bearings were not
encountered on most machinery, and oiling and greasing were a more common activity
than they are today. For example, automotive chassis used to require "lube jobs" nearly as
often as engine oil changes, but today's car chassis are mostly sealed for life. From the
late 1700s through mid 1900s, industry relied on many workers called oilers to lubricate
machinery frequently with oil cans.
34
Factory machines today usually have lube systems, in which a central pump serves
periodic charges of oil or grease from a reservoir through lube lines to the various lube
points in the machine's bearing surfaces, bearing journals, pillow blocks, and so on. The
timing and number of such lube cycles is controlled by the machine's computerized
control, such as PLC or CNC, as well as by manual override functions when occasionally
needed. This automated process is how all modern CNC machine tools and many other
modern factory machines are lubricated. Similar lube systems are also used on
nonautomated machines, in which case there is a hand pumpthat a machine operator is
supposed to pump once daily (for machines in constant use) or once weekly. These are
called one-shot systems from their chief selling point: one pull on one handle to lube the
whole machine, instead of a dozen pumps of an alemite gun or oil can in a dozen
different positions around the machine.
The oiling system inside a modern automotive or truck engine is similar in concept to the
lube systems mentioned above, except that oil is pumped continuously. Much of this oil
flows through passages drilled or cast into the engine block and cylinder heads, escaping
through ports directly onto bearings, and squirting elsewhere to provide an oil bath. The
oil pump simply pumps constantly, and any excess pumped oil continuously escapes
through a relief valve back into the sump.
Many bearings in high-cycle industrial operations need periodic lubrication and cleaning,
and many require occasional adjustment, such as pre-load adjustment, to minimise the
effects of wear.
Bearing life is often much better when the bearing is kept clean and well lubricated.
However, many applications make good maintenance difficult. For example, bearings in
35
the conveyor of a rock crusher are exposed continually to hard abrasive particles.
Cleaning is of little use, because cleaning is expensive yet the bearing is contaminated
again as soon as the conveyor resumes operation. Thus, a good maintenance program
might lubricate the bearings frequently but not include any disassembly for cleaning. The
frequent lubrication, by its nature, provides a limited kind of cleaning action, by
displacing older (grit-filled) oil or grease with a fresh charge, which itself collects grit
before being displaced by the next cycle.
These are bearing images
36
(Internal and external parts)
Operation on lathe machine
Lathe machine
A lathe is a machine tool which rotates the workpiece on its axis to perform various
operations such as cutting, sanding, knurling, drilling, or deformation, facing, turning,
with tools that are applied to the workpiece to create an object which has symmetry about
anaxis of rotation.
37
Lathes are used in woodturning, metalworking, metal spinning, Thermal spraying/ parts
reclamation, and glass-working. Lathes can be used to shape pottery, the best-known
design being the potter's wheel. Most suitably equipped metalworking lathes can also be
used to produce most solids of revolution, plane surfaces and screw threads or helices.
Ornamental lathes can produce three-dimensional solids of incredible complexity. The
material can be held in place by either one or two centers, at least one of which can be
moved horizontally to accommodate varying material lengths. Other work-holding
methods include clamping the work about the axis of rotation using a chuck or collet, or
to a faceplate, using clamps or dogs.
Examples of objects that can be produced on a lathe include candlestick holders,gun
barrels, cue sticks, table legs, bowls, baseball bats, musical instruments
(especially woodwind instruments), crankshafts, and camshafts.
38
turning operation
facing operation
turning operation
Turning is a machining process in which a cutting tool, typically a non-rotary tool bit,
describes a helical toolpath by moving more or less linearly while the workpiece rotates.
The tool's axes of movement may be literally a straight line, or they may be along some
set of curves or angles, but they are essentially linear (in the nonmathematical sense).
Usually the term "turning" is reserved for the generation of external surfaces by this
cutting action, whereas this same essential cutting action when applied
to internal surfaces (that is, holes, of one kind or another) is called "boring". Thus the
phrase "turning and boring" categorizes the larger family of (essentially similar)
processes. The cutting of faces on the workpiece (that is, surfaces perpendicular to its
rotating axis), whether with a turning or boring tool, is called "facing", and may be
lumped into either category as a subset.
Turning can be done manually, in a traditional form of lathe, which frequently requires
continuous supervision by the operator, or by using an automated lathe which does not.
Today the most common type of such automation is computer numerical control, better
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known as CNC. (CNC is also commonly used with many other types of machining
besides turning.)
When turning, a piece of relatively rigid material (such as wood, metal, plastic, or stone)
is rotated and a cutting tool is traversed along 1, 2, or 3 axes of motion to produce precise
diameters and depths. Turning can be either on the outside of the cylinder or on the inside
(also known as boring) to produce tubular components to various geometries. Although
now quite rare, early lathes could even be used to produce complex geometric figures,
even theplatonic solids; although since the advent of CNC it has become unusual to use
non-computerized toolpath control for this purpose.
The turning processes are typically carried out on a lathe, considered to be the oldest
machine tools, and can be of four different types such as straight turning, taper
turning,profiling or external grooving. Those types of turning processes can produce
various shapes of materials such as straight, conical, curved, or grooved workpiece. In
general, turning uses simple single-point cutting tools. Each group of workpiece materials
has an optimum set of tools angles which have been developed through the years.
The bits of waste metal from turning operations are known as chips . In some areas they
may be known as turnings.
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(turning of rod)
(finish turning)
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so we can say that turning is That operation is one of the most
basic machining processes. That is, the part is rotated while a single point cutting tool is
moved parallel to the axis of rotation.[1] Turning can be done on the external surface of
the part as well as internally (boring). The starting material is generally a workpiece
generated by other processes such ascasting, forging, extrusion, or drawing.
Facing operation
n machining, facing is the act of cutting a face, which is a planar surface, onto the
workpiece. Within this broadest sense there are various specific types of facing, with the
two most common being facing in the course of turning and boring work (facing planes
perpendicular to the rotating axis of the workpiece) and facing in the course
of milling work (for example, face milling). Other types of machining also cut faces (for
example, planing, shaping, and grinding), although the term "facing" may not always be
employed there.
Spotfacing is the facing of spots (localized areas), such as the bearing surfaces on
which bolt heads or washers will sit
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( facing operation )
Welding
Welding is a fabrication or sculptural process that joins materials,
usually metals orthermoplastics, by causing coalescence. This is often done
by melting the workpieces and adding a filler material to form a pool of molten material
(the weld pool) that cools to become a strong joint, with pressure sometimes used in
conjunction with heat, or by itself, to produce the weld. This is in contrast
with soldering and brazing, which involve melting a lower-melting-point material
between the workpieces to form a bond between them, without melting the workpieces.
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Many different energy sources can be used for welding, including a gas flame, an electric
arc, a laser, an electron beam, friction, and ultrasound. While often an industrial process,
welding may be performed in many different environments, including open air, under
waterand in outer space. Welding is a potentially hazardous undertaking and precautions
are required to avoid burns, electric shock, vision damage, inhalation of poisonous gases
and fumes, and exposure to intense ultraviolet radiation.
Until the end of the 19th century, the only welding process was forge welding,
whichblacksmiths had used for centuries to join iron and steel by heating and
hammering. Arc welding and oxyfuel welding were among the first processes to develop
late in the century, and electric resistance welding followed soon after. Welding
technology advanced quickly during the early 20th century as World War I and World
War II drove the demand for reliable and inexpensive joining methods. Following the
wars, several modern welding techniques were developed, including manual methods
like shielded metal arc welding, now one of the most popular welding methods, as well as
semi-automatic and automatic processes such as gas metal arc welding, submerged arc
welding, flux-cored arc weldingand electroslag welding. Developments continued with
the invention of laser beam welding, electron beam welding, electromagnetic pulse
welding and friction stir welding in the latter half of the century. Today, the science
continues to advance. Robot welding is commonplace in industrial settings, and
researchers continue to develop new welding methods and gain greater understanding of
weld quality.
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Arc welding process
Arc
These processes use a welding power supply to create and maintain an electric arc
between an electrode and the base material to melt metals at the welding point. They can
use either direct (DC) or alternating (AC) current, and consumable or non-
consumableelectrodes. The welding region is sometimes protected by some type of inert
or semi-inert gas, known as a shielding gas, and filler material is sometimes used as well.
Power supplies
To supply the electrical power necessary for arc welding processes, a variety of different
power supplies can be used. The most common welding power supplies are
constant current power supplies and constant voltage power supplies. In arc welding, the
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length of the arc is directly related to the voltage, and the amount of heat input is related
to the current. Constant current power supplies are most often used for manual welding
processes such as gas tungsten arc welding and shielded metal arc welding, because they
maintain a relatively constant current even as the voltage varies. This is important
because in manual welding, it can be difficult to hold the electrode perfectly steady, and
as a result, the arc length and thus voltage tend to fluctuate. Constant voltage power
supplies hold the voltage constant and vary the current, and as a result, are most often
used for automated welding processes such as gas metal arc welding, flux cored arc
welding, and submerged arc welding. In these processes, arc length is kept constant, since
any fluctuation in the distance between the wire and the base material is quickly rectified
by a large change in current. For example, if the wire and the base material get too close,
the current will rapidly increase, which in turn causes the heat to increase and the tip of
the wire to melt, returning it to its original separation distance.[1]
The type of current used also plays an important role in arc welding. Consumable
electrode processes such as shielded metal arc welding and gas metal arc welding
generally use direct current, but the electrode can be charged either positively or
negatively. In welding, the positively charged anode will have a greater heat
concentration, and as a result, changing the polarity of the electrode has an impact on
weld properties. If the electrode is positively charged, the base metal will be hotter,
increasing weld penetration and welding speed. Alternatively, a negatively charged
electrode results in more shallow welds.[2] Nonconsumable electrode processes, such as
gas tungsten arc welding, can use either type of direct current, as well as alternating
current. However, with direct current, because the electrode only creates the arc and does
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not provide filler material, a positively charged electrode causes shallow welds, while a
negatively charged electrode makes deeper welds.[3] Alternating current rapidly moves
between these two, resulting in medium-penetration welds. One disadvantage of AC, the
fact that the arc must be re-ignited after every zero crossing, has been addressed with the
invention of special power units that produce a square wave pattern instead of the
normal sine wave, making rapid zero crossings possible and minimizing the effects of the
problem.
Process of welding
One of the most common types of arc welding is shielded metal arc welding (SMAW);
[5] it is also known as manual metal arc welding (MMA) or stick welding. Electric current
is used to strike an arc between the base material and consumable electrode rod, which is
made of filler material (typically steel) and is covered with a flux that protects the weld
area from oxidation and contamination by producing carbon dioxide (CO2) gas during the
welding process. The electrode core itself acts as filler material, making a separate filler
unnecessary.
he process is versatile and can be performed with relatively inexpensive
equipment, making it well suited to shop jobs and field work.[5][6] An operator can become
reasonably proficient with a modest amount of training and can achieve mastery with
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experience. Weld times are rather slow, since the consumable electrodes must be
frequently replaced and because slag, the residue from the flux, must be chipped away
after welding.[5]Furthermore, the process is generally limited to welding ferrous materials,
though special electrodes have made possible the welding of cast iron, nickel,
aluminum, copper, and other metals.
Diagram of arc and weld area, in shielded metal arc welding
1. Coating Flow
2. Rod
3. Shield Gas
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4. Fusion
5. Base metal
6. Weld metal
7. Solidified Slag
Gas metal arc welding (GMAW), also known as metal inert gas or MIG welding, is a
semi-automatic or automatic process that uses a continuous wire feed as an electrode and
an inert or semi-inert gas mixture to protect the weld from contamination. Since the
electrode is continuous, welding speeds are greater for GMAW than for SMAW.[7]
A related process, flux-cored arc welding (FCAW), uses similar equipment but uses wire
consisting of a steel electrode surrounding a powder fill material. This cored wire is more
expensive than the standard solid wire and can generate fumes and/or slag, but it permits
even higher welding speed and greater metal penetration.[8]
Gas tungsten arc welding (GTAW), or tungsten inert gas (TIG) welding, is a manual
welding process that uses a nonconsumable tungsten electrode, an inert or semi-inert gas
mixture, and a separate filler material.[9] Especially useful for welding thin materials, this
method is characterized by a stable arc and high quality welds, but it requires significant
operator skill and can only be accomplished at relatively low speeds.[9]
GTAW can be used on nearly all weldable metals, though it is most often applied
tostainless steel and light metals. It is often used when quality welds are extremely
important, such as in bicycle, aircraft and naval applications.[9] A related process, plasma
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arc welding, also uses a tungsten electrode but uses plasma gas to make the arc. The arc
is more concentrated than the GTAW arc, making transverse control more critical and
thus generally restricting the technique to a mechanized process. Because of its stable
current, the method can be used on a wider range of material thicknesses than can the
GTAW process and it is much faster. It can be applied to all of the same materials as
GTAW except magnesium, and automated welding of stainless steel is one important
application of the process. A variation of the process is plasma cutting, an efficient steel
cutting process.[10]
Submerged arc welding (SAW) is a high-productivity welding method in which the arc is
struck beneath a covering layer of flux. This increases arc quality, since contaminants in
the atmosphere are blocked by the flux. The slag that forms on the weld generally comes
off by itself, and combined with the use of a continuous wire feed, the weld deposition
rate is high. Working conditions are much improved over other arc welding processes,
since the flux hides the arc and almost no smoke is produced. The process is commonly
used in industry, especially for large products and in the manufacture of welded pressure
vessels.[11] Other arc welding processes include atomic hydrogen welding, electroslag
welding, electrogas welding, and stud arc welding
Tools
Tools used during the making projects
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hacksaw
blade
file
scale
drill
etc.
Hacksaw
A hacksaw is a fine-tooth hand saw with a blade held under tension in a frame, used
forcutting materials such as metal or plastics. Hand-held hacksaws consist of a metal
arch with a handle, usually a pistol grip, with pins for attaching a narrow disposable
blade. A screw or other mechanism is used to put the thin blade under tension. The
blade can be mounted with the teeth facing toward or away from the handle, resulting
in cutting action on either the push or pull stroke. On the push stroke, the arch will
flex slightly, decreasing the tension on the blade, often resulting in an increased
tendency of the blade to buckle and crack. Cutting on the pull stroke increases the
blade tension and will result in greater control of the cut and longer blade life
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Blade
Blades are available in standardized lengths, usually 10 or 12 inches for a standard hand
hacksaw. "Junior" hacksaws are half this size. Powered hacksaws may use large blades in
a range of sizes, or small machines may use the same hand blades.
The pitch of the teeth can be anywhere from fourteen to thirty-two teeth per inch (tpi) for
a hand blade, with as few as three tpi for a large power hacksaw blade. The blade chosen
is based on the thickness of the material being cut, with a minimum of three teeth in the
material. As hacksaw teeth are so small, they are set in a "wave" set. As for other saws
they are set from side to side to provide a kerfor clearance when sawing, but the set of a
hacksaw changes gradually from tooth to tooth in a smooth curve, rather than alternate
teeth set left and right.
Hacksaw blades are normally quite brittle, so care needs to be taken to prevent brittle
fracture of the blade. Early blades were of carbon steel, now termed 'low alloy' blades,
and were relatively soft and flexible. They avoided breakage, but also wore out rapidly.
Except where cost is a particular concern, this type is now obsolete. 'Low alloy' blades
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are still the only type available for the Junior hacksaw, which limits the usefulness of this
otherwise popular saw.
For several decades now, hacksaw blades have used high speed steel for their teeth,
giving greatly improved cutting and tooth life. These blades were first available in the
'All-hard' form which cut accurately but were extremely brittle. This limited their
practical use to benchwork on a workpiece that was firmly clamped in a vice. A softer
form of high speed steel blade was also available, which wore well and resisted breakage,
but was less stiff and so less accurate for precise sawing. Since the 1980s, bi-metal blades
have been used to give the advantages of both forms, without risk of breakage. A strip of
high speed steel along the tooth edge is electron beam welded to a softer spine. As the
price of these has dropped to be comparable with the older blades, their use is now almost
universl
hacksaw blade
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File
A file is a metalworking, woodworking and plastic working tool used to cut fine amounts
of material from a workpiece. It most commonly refers to the hand tool style, which takes
the form of a steel bar with a case hardened surface and a series of sharp, parallel teeth.
Most files have a narrow, pointed tang at one end to which a handle can be fitted.[1]
A similar tool is the rasp. This is an older form, with simpler teeth. As they have larger
clearance between teeth, these are usually used on softer, non-metallic materials.
Related tools have been developed with abrasive surfaces, such as diamond
abrasives orsilicon carbide. Because of their similar form and function, these have also
been termed 'files'.
( file )
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( FINAL PROJECT )
By using all this process , gears , operation and tools we have completed our project
This are our project images as
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