1. AUTOMATIC GLASS PRINTING MACHINE Page 1
AUTOMATIC GLASS PRINTING
MACHINE
A
DISSERTATION SUBMITTED TO
MAHARISHI MARKANDESHWAR UNIVERSITY, MULLANA,
In the partial fulfilment for the degree of
Bachelor of technology
(Session 2010-14)
Under the supervision of: Submitted By:
Dr. R.C. Sharma Sanyam Jain (11100975)
Professor, MMEC, Mullana Sandeep (11100972)
Prof. N.K. Batra Rahul Dogra (11100965)
HOD, Mechanical Deptt. Aditya Dev Singh (11102304)
Jatin Bindra (2308909)
Kapil kumar (11102317)
MAHARISHI MARKANDESHWAR ENGG. COLLEGE
AFFILIATED TO:
MAHARISHI MARKANDESHWAR UNIVERSITY, MULLANA
AMBALA-HARYANA,133203,INDIA
2. AUTOMATIC GLASS PRINTING MACHINE Page 2
DECLARATION
We hereby declare that the work which is being presented in this report
entitled “AUTOMATIC GLASS PRINTING MACHINE” by us is in partial fulfilment
of the requirement for the award of degree of bachelors of technology in
mechanical submitted in the department of mechanical engineering of
maharishi markandeshwar engineering college is a authentic record under the
supervision of Dr.R.C. Sharma
3. AUTOMATIC GLASS PRINTING MACHINE Page 3
ACKNOWLEDGEMENT
I take this opportunity to express my profound gratitude and deep regards to
my guide DR.R.C.SHARMA and H.O.D. MR.N.K. BATRA for his exemplary
guidance, monitoring and constant encouragement throughout the course of
this project “AUTOMATIC GLASS PRINTING MACHINE”. The blessing, help and
guidance given by him time to time shall carry me a long way in the journey of
life on which I am about to embark.
5. AUTOMATIC GLASS PRINTING MACHINE Page 5
BILL OF MATERIAL
NAME SPECIFICATION QUANTITY
Electric motor ¼ hp single phase 1
Reduction gearbox 40:1 ratio 1
Cams Radial 2
Sprockets 16,32,40 teeth 7
Roller chain 0.5 inch 1
Shafts As per design 4
Rectangular links As per design 6
Bearings As per design 12
Cams As per design 2
Springs As per design 3
Nuts and bolts As per design As per design
Sheet screws As per design 2
Cast iron angle 1 inch 4
Cast iron sheet 10 mm thick 1
Square rods 25 mm 2
Rubber brush 40 mm 1
Electric switch Single phase 1
6. AUTOMATIC GLASS PRINTING MACHINE Page 6
HIGHLIGHTS OF MACHINE
Fully automatic machine based on mechanical
system using cams and chain drive
Can print on complete 360
◦
of the work piece
No electronic component, no PLC, no computer
programming is used for automation
Single motor is engaged for every movement in
the machine
Variable gear box can be employed for variation
of speed
Chain drive is used for power transmission
Can print 2000-3000 test tubes in an hour
V plate type conveyor is used, this conveyor can
be connected to worm conveyor for heating
purpose which has minimum heat loss in
furnace
7. AUTOMATIC GLASS PRINTING MACHINE Page 7
WHAT IS SCREEN PRINTING
INTRODUCTION
Screen printing is simply a process used for making prints of the same design
.Screen printing uses a stencil with open areas through which ink or paint
passes and solid areas as a mask preventing the passage of ink. When the
fabric - covered frame is used the process is often called as “silk screening”
because was originally used as the fabric of choice.
The procedures described in this handout can be used for printing on either
paper or fabric. There are several methods that can be used to produce the
stencil and screen and a variety of inks and paints that can be used. In some
cases, alternative methods are described.
This silk screening method is inexpensive and allow girls to be involved in the
actual printing process. However, it is important to remind them that even
though they are using a stencil, they are creating an original work of art. The
amount of ink, the pressure applied, and the care taken with the screen will
effect their finished design. If you are looking for perfect , identical shirts, you
should use a different method.
Materials
The following materials will be necessary or useful throughout the process:
Silk screen frame and fabric
Photo emulsion kit
Screen filler
Photo emulsion remover
Soft nylon brush
Dish washer detergent
Masking tape
Small Paint brush
Small blocks of wood
Craft sticks
Glass or Plexiglas
Squeegee
8. AUTOMATIC GLASS PRINTING MACHINE Page 8
GETTING READY
THE SCREEN: A silk screen frame is simply any frame over which a fine mesh
fabric can be stretched and secured. Pre –made frames complete with
Stretched fabric are easiest .Frames can also assembled from precut pieces at
art supply stores , but this can be challenging. Most people will use prepared
frame.
The fabric is attached to the frame and stretched tightly and uniformly. Fabric
should be cut atleast larger the frame on the all sides. If using a frame with a c
fabric channel is centered over the channel side of the frame loosely
thumbtacked to the corners. A spline or chord is gently tapped into the grove
and the thumbtacks removed.
The cord is then set in the groove by using a spline or cordoing tool or tapping
it into place with a hammer and wedge such as a wide screwdriver. This
method allow for easy removal of the fabric when required. Fabric can also be
more easily cause tears in the fabric.
In all cases, the fabric must be clean and factory sizing removed to allow
photosensitive chemicals to adhere to the screen.do this by scrubbing the
fabric with a soft nylon brush and a solution of dish washer powder mixed with
water. Thoroughly rinse and allow screen to dry.
PRINTING BOARD
A printing board is essential for professional quality print especially where
more than one color is used or where uniformly of the prints is essential.
THE PHOTO EMULSION MATERIAL
Creation of a photographic stencil utilizes light sensitive material which
hardens when exposed to light. A thick syrupy liquid emulsion is used to coat
both sides of the fabric. Once dry the design is placed on the screen and
exposed to light . The light hardens the emulsion in area of the screen not
blocked out by the positive created from your design.
There are two types of chemicals which can be used and r generally readily
available BICHROMATE OR DIAZO each uses an emulsion that is not light
sensitive and makes up the bulk of material . a small amount of sensitizer
either diazo bis added , the biochronate emulsion is designed for quickly
exposure and can be used with most kinds of ink.
9. AUTOMATIC GLASS PRINTING MACHINE Page 9
Diazo sensitinzed emulsion last longer and can be stored up to 3 months at
room temperature and up to 6 months if refrigerated . screens coated with a
diazo mixture can be stored up to 8 weeks if not exposed to light the diazo has
less toxicity and no known environmental problems associated with it.
The squeegee is used to apply the ink . squeegees can be made with a plastic
wooden or aluminium handle. All use a rubber blade that is either removable
for easier cleaning or permanently attached to handle. Squeegee come in
different lengths. You generally want to use a squeegee that will cover the
areas is one pass.
INK
This is being printed how it will be used and any he type of ink used will
depened on what is being printed how it will be used and any special effects
desired . When printing on fabric it is important to use textile ink. Water
soluble ink is recommended because it is easier to clean up.
SCREEN FILLER
Screen filler can be painted on the screen to fill in areas that you do not want
to print. It is very useful in covering pinholes or other flaws that appear in the
fabric after exposing it to the light.
DESIGN
The part of your design that is black on your drawing will be the part that
accepts the colored ink. Areas that are white in your drawing will remain the
colour of the fabric or other background material. As you become more
experienced.
Your ultimate goal is to create a stencil but the method described here will be
for creating a photographic stencil. Once you have a black and white design,
you are ready to copy it onto clear acetate also known as transparency film or
overhead film. This method produces the most accurate copy of the design and
allows the most complicated design to turned into a screen stencil. Be sure to
check that the copier is producing clean copies. You will need 3-4 copies to
assure light does not show through the darkened areas. Carefully line up
copies and tape them together copies. Your resulting sheet is called as
“positive”.
10. AUTOMATIC GLASS PRINTING MACHINE Page 10
PREPARING THE SCREEN
Since emulsions react to the U.V rays but less readily to incandescent light. It is
possible to prepare the mixtures and the screen using normal room light,
although it is best to work with the little direct bright light as necessary. Cover
work in newspapers. Mix photo emulsions solution according to the directions.
Place the screen on the work surface with the flat fabric side up. Using a
squeegee or piece of stiff cardboard spread the emulsion evenly. Turn screen
over. Repeat the coating procedure on the inside of the frame. Screen should
be dried in the dark room such as closet. Screen will generally dry in 3 hours. A
fan will speed the drying process. When dry, apply a second coat on the
bottom if more than 200 prints will be made.
PLACING POSITIVE
You should consider where and you will expose your screen outside, you will
need to set it up so it can be carried outside when ready. A shallow box with lid
works well. if you r going to expose it inside , you can set up in position using
dim room light and position the lamp the correct distance.
EXPOSING THE SCREEN
The screen can be exposed to either sunlight or artificial but direct sunlight, if
available is preferable since exposure time is considerably shorter. Exposure
time depend on intensity of light source and the type of emulsion used.
For outdoor exposure place screen in box or cover with opaque prevent
exposure until ready carrying prepared screen to a sunny location. Length of
exposure time will depend on intensity of light and the type of emulsion used.
Do not do this if it is raining or sprinkling since this will begin to wash chemicals
before they are hardened.
At the end of exposure time immediately cover remove the positive and glass
if used and the wash screen with forceful spray of taped water. Design area
should appear lighter than exposed area. Use masking paste tape or screen
filter to cover these holes . If screen filler is used allow it to dry.
11. AUTOMATIC GLASS PRINTING MACHINE Page 11
MAKING PRINTS
Printing can be done on a variety of poor textiles although cotton or poly
cotton works best . Ink generally will not adhere to high holes or plastic
coated papers.in some cases it is recommended that fabrics be washed and
dried before adhering or interference with permanency of the ink.
When printing on t shirt place a piece of smooth cardboard inside the t shirt so
ink does not seep through to the back of the shirt, make sure fabric is smooth
and free of wrinkles . Different fabrics accept ink differently so a test print
should be made.
Place screen bottom side down directly on top of them. In this method the
stenciled fabric touches the screen only when forced down by the squeegee so
that ink left on the screen from the previous prints will not create a double
image on the item.
To begin printing, pour or spoon a small amount of ink along one edge of
screen. Make sure screen in held tightly in place either with one hand or with
another person helping. Using a squeegee, slowly dark ink to the opposite side
of the screen witthout pressing down. This first stroke is the “flood stroke”
and it fills the screen with ink. When inking is done rest squeegee along one
edge of the screen and carefully lift screen of shirt. Screen should be used
immediately for the next item. For jobs making multiple prints. It is advisable
to make 2 or more screens. This way one screen can be washed and allowed to
dry while a 2nd
screen is used.
CLEANUP
When all prints have been made, scrape excess ink from screen and thoroughly
wash all ink from screen using warm water and mild soap. If the design is not
of use further, wash remaining photo emulsion off so used for a different
design. It may be necessary to gently scrub the screen with a nylon brush to
remove all emulsion. Hold screen up to the light to be sure as all ink and
emulsion can be removed. Remember to clean all the squeegee. If the
squeegee has are movable rubber blade, remove it and clean it in grove.
12. AUTOMATIC GLASS PRINTING MACHINE Page 12
PRINTING MORE THAN ONE SCREEN
If a multi colored print is desired, it can be done either using a single screen
and blocking off desired sections, or by making a separate screen for each
colour. If a single screen is used, cover areas you don’t want using masking
tape. When ready to use , uncover the area , wash and dry the screen , and
reposition the mask. Try the position tape so it will not damage the design.
13. AUTOMATIC GLASS PRINTING MACHINE Page 13
CHAIN DRIVES
Introduction
Three major types of chain are used for power transmission: roller, engineering
steel, and silent. Roller chains are probably the most common and are used in
a wide vari-ety of low-speed to high-speed drives. Engineering steel chains are
used in many low-speed, high-load drives. Silent chains are mostly used in
high-speed drives. Other types of standard chains, and many types of special
chains for unique applica-tions, may be found in manufacturers’ catalogs.
Chains can span long center distances like belts, and positively transmit speed
and torque like gears. For a given ratio and power capacity, chain drives are
more compact than belt drives, but less compact than gear drives. Mounting
and alignment of chain drives does not need to be as precise as for gear drives.
Chain drives can operate at 98 to 99 percent efficiency under ideal conditions.
Chain drives are usu-ally less expensive than gear drives and quite competitive
with belt drives.
Chain drives can be dangerous. Provide proper guarding to prevent personnel
from coming in contact with, or being caught in, a running drive. Any chain can
break from unexpected operating conditions. If a chain breaks at speed, it can
be thrown off the drive with great force and cause personal injury and
property damage. Provide adequate guarding to contain a broken chain or to
prevent personnel from entering an area where they might be struck by a
broken chain. A broken chain can sometimes release a load and cause personal
injury and property damage. Provide an adequate brake or restraint to stop
and hold the load in case of a chain breakage
Roller Chains
Standard Roller Chains. A portion of a typical roller-chain drive is shown in Fig.
15.1. The American National Standards Institute (ANSI) has standardized
limiting dimensions, tolerances, and minimum ultimate tensile strength for
chains and sprockets of 0.25 to 3.0 in pitch [15.1]. The chain pitch is the
distance between suc-cessive roller, or bushing, centers, and is the basic
dimension for designating roller chains. The standard includes both standard
and heavy series chains.
Multiple-Strand Roller Chains. Multiple-strand roller chains consist of two or
more parallel strands of chain assembled on common pins. They also are
standard-ized [15.1].
14. AUTOMATIC GLASS PRINTING MACHINE Page 14
Double-Pitch Roller Chains. Double-pitch roller chains are standardized in Ref.
[15.2]. Double-pitch chains have the same pin, bushing, and roller dimensions
as cor-
responding chains in Ref. [15.1], but the pitch of the link plates is twice as long.
The standard [15.2] covers chains of 1.0 to 4.0 in pitch.
Nonstandard Roller Chains. Many manufacturers offer high-strength, extra-
clearance, sintered metal bushing, sealed-joint, and corrosion-resistant chains
for special applications or adverse environments. These chains are not covered
by any standard, but most are designed to run on standard sprockets.
Sprockets. Roller-chain sprockets have precisely designed, radiused pockets
which smoothly engage the rollers on the chain and positively transmit torque
and motion. Driver sprockets receive power from the prime mover and
transfer it to the chain. Driven sprockets take power from the chain and
transfer it to the selected machinery. Idler sprockets transmit no power; they
are used to take up slack chain, increase the amount of chain wrap on another
sprocket, guide the chain around other machine members, and reverse the
normal direction of rotation of another sprocket.
15. AUTOMATIC GLASS PRINTING MACHINE Page 15
ROLLER CHAINS: NOMENCLATURE AND
DIMENSIONS
Standard Roller-Chain Nomenclature
Roller Chain. Roller chain is an assembly of alternating roller links and pin links
in which the pins pivot inside the bushings, and the rollers, or bushings, engage
the sprocket teeth to positively transmit power, as shown in Fig. 15.1 and the
illustration with Table 15.1.
Roller Links. Roller links are assemblies of two bushings press-fitted into two
roller link plates with two rollers free to rotate on the outside of each of the
bushings.
Pin Links. Pin links are assemblies of two pins press-fitted into two pin link
plates.
Connecting Links. Connecting links are pin links in which one of the pin link
plates is detachable and is secured either by a spring clip that fits in grooves on
the ends of the pins or by cotters that fit in cross-drilled holes through the
ends of the pins. Illustrations of connecting links may be found in Ref. [15.1] or
[15.4] or in man-ufacturers’ catalogs.
Offset Links. Offset links are links in which the link plates are bent to accept a
bushing in one end and a pin in the other end. The pin may be a press fit in the
link plates, or it may be a slip fit in the link plates and be secured by cotters.
Illustrations of offset links may be found in Ref. [15.1] or [15.4] or in
manufacturers’ catalogs.
17. AUTOMATIC GLASS PRINTING MACHINE Page 17
Roller-Chain Sprockets
Definitions and Types. Four styles of sprockets are standardized in Ref. [15.1].
Style A is a flat plate with no hub extensions. Style B has a hub extension on
one side of the plate (flange). Style C has hub extensions on both sides of the
flange. The extensions do not have to be equal. Style D has a detachable hub.
The style D hub is normally attached to the flange with bolts. Most sprockets
have a central bore with a keyway and setscrew to mount them on a shaft.
Many other configurations of sprocket hubs and bores may be found in
manufacturers’ catalogs.
Tooth Form. The tooth form and profile dimensions for single- and multiple-
strand roller-chain sprockets are defined in Ref. [15.1].
Sprocket Diameters. There are five important sprocket diameters defined in
Ref. [15.1]. They are pitch, outside, bottom, caliper, and maximum hub
diameters. The equations for those diameters, shown in Fig. 15.2, are
PD =P/sin (180/N) OD =P[0.6 cot (180/N)]
BD PD − D CD =PD cos (90/N) − D
MHD = P[cot (180/N) − 1] − 0.030
19. AUTOMATIC GLASS PRINTING MACHINE Page 19
Types of Chain Lubrication
All three types of chain drives—roller, engineering steel, and silent—will work
with three types of lubrication system. The type of lubrication system used is
dependent on the speed and the amount of power transmitted. The three
types of chain drive lubrication systems are
Type 1. Manual or drip
Type 2. Oil bath or slinger disk
Type 3. Oil stream
A description of each type of lubrication follows.
Manual. Oil is manually applied periodically with a brush or spout can. The
time period between applications is often 8 hours, but it may be longer if this is
proven adequate for the particular conditions.
Drip. Oil is dripped between the link plate edges from a lubricator with a reser-
voir. Rates range from 4 to 20 drops per minute; 10 drops per minute is equal
to about one ounce per hour. A distribution pipe is needed to direct oil to all
the rows of link plates in multiple-strand chain, and a wick packing in the pipe
will ensure uni-form distribution of oil to all the holes in the pipe. Windage
may misdirect the oil droplets. If that occurs, the lubricator must be relocated.
Oil Bath. A short section of chain runs through the oil in the sump of a chain
cas-ing. The oil level should not be higher than the pitch line of the chain at its
lowest point in operation. Long sections of chain running through the oil bath
can cause foaming and overheating. If that occurs, slinger disk–type lubrication
should be considered.
Slinger Disk. The chain runs above the oil level while a disk on one shaft picks
up oil from the sump and slings it against a collector plate. The oil is then
directed into a trough which applies it to the upper edges of the chain link
plates in the lower span of the chain. The disk diameter should be sized so that
the disk runs at a rim speed of 600 to 8000 ft/min. Slower speeds will not
effectively pick up the oil. Higher speeds can cause foaming and overheating.
Oil Stream. A pump sends a stream or spray of oil under pressure onto the
chain. The oil must be applied evenly across the entire width of the chain, and
20. AUTOMATIC GLASS PRINTING MACHINE Page 20
it must be directed onto the lower span from the inside of the chain loop.
Excess oil is collected in the sump and returned to the pump reservoir. The oil
stream both lubricates and cools the chain when high power is transmitted at
high speeds (Table 15.5). The oil may be cooled by radiation from the external
surfaces of the reservoir or, if power is very high, by a separate heat
exchanger.
21. AUTOMATIC GLASS PRINTING MACHINE Page 21
REDUCTION GEARBOX
Introduction:
The purpose of a gear reduction system is to convert input an speed and torque into a
different output speed and torque. The design at hand requires the use of two gears whose
diameters are specified at 24 and 12 inches each. These gears are attached to a shaft whose
diameter is specified at two inches, and the bearings, keys, gears, speeds, safety factors, etc
need to be determined from statics, strengths, fatigue, and various other design
considerations.
The gears are crucial elements of this system. They transmit the power and act as the
reducers of velocity to the other parts. They need to be carefully engineered and considered
if the design is to be successful. The Bearings need to provide the smoothness to the
motion, while still withstanding the loads to which the system is subjected. The keys hold
the shaft and the gears together. The shaft holds everything and provides uniform rotation
to all the parts. It is, therefore, key to design these elements so that they can interact with
one another in perfect harmony and still achieve their goal.
22. AUTOMATIC GLASS PRINTING MACHINE Page 22
A worm drive is a gear arrangement in which a worm (which is a gear in the
form of a screw) meshes with a worm gear (which is similar in appearance to a
spur gear, and is also called a worm wheel). The terminology is often confused
by imprecise use of the term worm gear to refer to the worm, the worm gear, or
the worm drive as a unit.
Like other gear arrangements, a worm drive can reduce rotational speed or
allow higher torque to be transmitted. The image shows a section of a gear box
with a worm gear being driven by a worm. A worm is an example of a screw,
one of the six simple machines.
A gearbox designed using a worm and worm-wheel will be considerably
smaller than one made from plain spur gears and has its drive axes at 90° to
each other. With a single start worm, for each 360° turn of the worm, the
worm-gear advances only one tooth of the gear. Therefore, regardless of the
worm's size (sensible engineering limits notwithstanding), the gear ratio is the
"size of the worm gear - to - 1". Given a single start worm, a 20 tooth worm
gear will reduce the speed by the ratio of 20:1. With spur gears, a gear of 12
teeth (the smallest size permissible, if designed to good engineering practices)
would have to be matched with a 240 tooth gear to achieve the same ratio of
20:1. Therefore, if the diametrical pitch (DP) of each gear was the same, then,
in terms of the physical size of the 240 tooth gear to that of the 20 tooth gear,
the worm arrangement is considerably smaller in volume.
There are three different types of gears that can be used in a worm drive.
The first are non-throated worm gears. These don't have a throat, or groove,
machined around the circumference of either the worm or worm wheel. The
second are single-throated worm gears, in which the worm wheel is throated.
The final type are double-throated worm gears, which have both gears throated.
This type of gearing can support the highest loading.
An enveloping (hourglass) worm has one or more teeth and increases in
diameter from its middle portion toward both ends.
Double-enveloping wormgearing comprises enveloping worms mated with fully
enveloping wormgears. It is also known as globoidal wormgearing
Unlike with ordinary gear trains, the direction of transmission (input shaft vs
output shaft) is not reversible when using large reduction ratios, due to the
greater friction involved between the worm and worm-wheel, when usually a
single start (one spiral) worm is used. This can be an advantage when it is
desired to eliminate any possibility of the output driving the input. If a multistart
23. AUTOMATIC GLASS PRINTING MACHINE Page 23
worm (multiple spirals) is used then the ratio reduces accordingly and the
braking effect of a worm and worm-gear may need to be discounted as the gear
may be able to drive the worm.
Worm gear configurations in which the gear cannot drive the worm are said to
be self-locking. Whether a worm and gear will be self-locking depends on the
lead angle, the pressure angle, and the coefficient of friction; however, it is
approximately correct to say that a worm and gear will be self-locking if the
tangent of the lead angle is less than the coefficient of friction.
In early 20th century automobiles prior to the introduction of power steering,
the effect of a flat or blowout on one of the front wheels will tend to pull the
steering mechanism toward the side with the flat tire. The employment of a
worm screw reduced this effect. Further development of the worm drive
employs recirculating ball bearings to reduce frictional forces, allowing some of
the steering force to be felt in the wheel as an aid to vehicle control and greatly
reducing wear, which leads to difficulties in steering precisely.
Worm drives are a compact means of substantially decreasing speed and
increasing torque. Small electric motors are generally high-speed and low-
torque; the addition of a worm drive increases the range of applications that it
may be suitable for, especially when the worm drive's compactness is
considered.
Worm drives are used in presses, rolling mills, conveying engineering, mining
industry machines, on rudders, and worm drive saws. In addition, milling heads
and rotary tables are positioned using high-precision duplex worm drives with
adjustable backlash. Worm gears are used on many lift/elevator and escalator-
drive applications due to their compact size and the non-reversibility of the
gear.
In the era of sailing ships, the introduction of a worm drive to control the rudder
was a significant advance. Prior to its introduction, a rope drum drive was used
to control the rudder, and rough seas could cause substantial force to be applied
to the rudder, often requiring several men to steer the vessel, with some drives
having two large-diameter wheels to allow up to four crewmen to operate the
rudder.
24. AUTOMATIC GLASS PRINTING MACHINE Page 24
Worm drives have been used in a few automotive rear-axle final drives
(although not the differential itself at this time). They took advantage of the
location of the gear being at either the very top or very bottom of the differential
crown wheel. In the 1910s they were common on trucks; to gain the most
clearance on muddy roads the worm gear was placed on top. In the 1920s the
Stutz firm used them on its cars; to have a lower floor than its competitors, the
gear was located on the bottom. An example from around 1960 was the Peugeot
404. The worm gear carries the differential gearing, which protects the vehicle
against rollback. This ability has largely fallen from favour due to the higher-
than-necessary reduction ratios.
A more recent exception to this is the Torsen differential, which uses worms
and planetary worm gears in place of the bevel gearing of conventional open
differentials. Torsen differentials are most prominently featured in the
HMMWV and some commercial Hummer vehicles, and as a center differential
in some all wheel drive systems, such as Audi's quattro. Very heavy trucks, such
as those used to carry aggregates, often use a worm gear differential for
strength. The worm drive is not as efficient as a hypoid gear, and such trucks
invariably have a very large differential housing, with a correspondingly large
volume of gear oil, to absorb and dissipate the heat created.
Worm drives are used as the tuning mechanism for many musical instruments,
including guitars, double-basses, mandolins, bouzoukis, and many banjos
(although most high-end banjos use planetary gears or friction pegs). A worm
drive tuning device is called a machine head.
Plastic worm drives are often used on small battery-operated electric motors, to
provide an output with a lower angular velocity (fewer revolutions per minute)
than that of the motor, which operates best at a fairly high speed. This motor-
worm-gear drive system is often used in toys and other small electrical devices.
25. AUTOMATIC GLASS PRINTING MACHINE Page 25
A worm drive is used on jubilee-type hose clamps or jubilee clamps; the
tightening screw has a worm thread which engages with the slots on the clamp
band.
Occasionally a worm gear is designed to be run in reverse, resulting in the
output shaft turning much faster than the input. Examples of this may be seen in
some hand-cranked centrifuges or the wind governor in a musical box.
26. AUTOMATIC GLASS PRINTING MACHINE Page 26
CAMS
INTRODUCTION
A cam is a mechanical device used to transmit motion to a follower by direct contact. The
driver
is called the cam and the driven member is called the follower. In a cam follower pair, the
cam
normally rotates while the follower may translate or oscillate. A familiar example is the
camshaft of an automobile engine, where the cams drive the push rods (the followers) to open
and close the valves in synchronization with the motion of the pistons.
Types of cams
Cams can be classified based on their physical shape.
a) Disk or plate cam (Fig. 6.1a and b): The disk (or plate) cam has an irregular contour to
impart a specific motion to the follower. The follower moves in a plane perpendicular to the
axis
of rotation of the camshaft and is held in contact with the cam by springs or gravity.
b) Cylindrical cam (Fig. 6.2): The cylindrical cam has a groove cut along its cylindrical
surface. The roller follows the groove, and the follower moves in a plane parallel to the axis
of
rotation of the cylinder.
27. AUTOMATIC GLASS PRINTING MACHINE Page 27
c) Translating cam (Fig. 6.3a and b). The translating cam is a contoured or grooved plate
sliding on a guiding surface(s). The follower may oscillate (Fig. 6.3a) or reciprocate (Fig.
6.3b).
The contour or the shape of the groove is determined by the specified motion of the follower.
Types of followers:
(i) Based on surface in contact
(a) Knife edge follower
(b) Roller follower
(c) Flat faced follower
(d) Spherical follower
(ii) Based on type of motion:
(a) Oscillating follower
(b) Translating follower
29. AUTOMATIC GLASS PRINTING MACHINE Page 29
Profile The contour of the working surface of the cam.
Tracer Point The point at the knife edge of a follower, or the center of a roller, or the center
of
a spherical face.
Pitch Curve The path of the tracer point.
Base Circle The smallest circle drawn, tangential to the cam profile, with its center on the
axis
of the camshaft. The size of the base circle determines the size of the cam.
Prime Circle The smallest circle drawn, tangential to the pitch curve, with its center on the
axis of the camshaft.
Pressure Angle The angle between the normal to the pitch curve and the direction of motion
of
the follower at the point of contact
Types of follower motion:
Cam follower systems are designed to achieve a desired oscillatory motion. Appropriate
displacement patterns are to be selected for this purpose, before designing the cam surface. The
cam is assumed to rotate at a constant speed and the follower raises, dwells, returns to its
original position and dwells again through specified angles of rotation of the cam, during each
revolution of the cam.
Some of the standard follower motions are as follows:
They are, follower motion with,
(a) Uniform velocity
(b) Modified uniform velocity
(c) Uniform acceleration and deceleration
(d) Simple harmonic motion
(e) Cycloidal motion
Displacement diagrams:
In a cam follower system, the motion of the follower is very
important. Its displacement can be plotted against the angular displacement θ of the cam and it is
called as the displacement diagram. The displacement of the follower is plotted along the y-axis
and angular displacement θ of the cam is plotted along x-axis. From the displacement diagram,
velocity and acceleration of the follower can also be plotted for different angular displacements
θ of the cam. The displacement, velocity and acceleration diagrams are plotted for one cycle of
operation i.e., one rotation of the cam. Displacement diagrams are basic requirements for the
construction of cam profiles. Construction of displacement diagrams and calculation of
velocities and accelerations of followers with different types of motions are discussed in the
following sections.
(a) Follower motion with Uniform velocity:
Fig.6.8 shows the displacement, velocity and acceleration patterns of a follower having uniform
velocity type of motion. Since the follower moves with constant velocity, during rise and fall,
the displacement varies linearly with θ. Also, since the velocity changes from zero to a finite
value, within no time, theoretically, the acceleration becomes infinite at the beginning and end of rise
and fall.
30. AUTOMATIC GLASS PRINTING MACHINE Page 30
Follower motion with modified uniform velocity:
It is observed in the displacement diagrams of the follower with uniform velocity that the
acceleration of the follower becomes infinite at the beginning and ending of rise and return
strokes. In order to prevent this, the displacement diagrams are slightly modified. In the
modified form, the velocity of the follower changes uniformly during the beginning and end of
each stroke. Accordingly, the displacement of the follower varies parabolically during these
periods. With this modification, the acceleration becomes constant during these periods, instead
of being infinite as in the uniform velocity type of motion. The displacement, velocity and
acceleration patterns are shown in fig.6.9.
31. AUTOMATIC GLASS PRINTING MACHINE Page 31
(c) Follower motion with uniform acceleration and retardation (UARM):
Here, the displacement of the follower varies parabolically with respect to angular displacement
of cam. Accordingly, the velocity of the follower varies uniformly with respect to angular
displacement of cam. The acceleration/retardation of the follower becomes constant
accordingly.The displacement, velocity and acceleration patterns are shown in fig. 6.10
32. AUTOMATIC GLASS PRINTING MACHINE Page 32
(d) Simple Harmonic Motion: In fig.6.11, the motion executed by point Pl, which is the
projection of point P on the vertical diameter is called simple harmonic motion. Here, P moves
with uniform angular velocity ωp, along a circle of radius r (r = s/2).
35. AUTOMATIC GLASS PRINTING MACHINE Page 35
BEARINGS
A bearing is a machine element that constrains relative motion and reduces
friction between moving parts to only the desired motion. The design of the
bearing may, for example, provide for free linear movement of 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.
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.
By far, the most common bearing is the plain bearing, a bearing which uses
surfaces in rubbing contact, often with a lubricant such as oil or graphite. A
plain bearing may or may not be a discrete device. It may be nothing more than
the bearing surface of a hole with a shaft passing through it, or of a planar
surface that bears another (in these cases, not a discrete device); or it may be a
layer of bearing metal either fused to the substrate (semi-discrete) or in the form
of a separable sleeve (discrete). With suitable lubrication, plain bearings often
give entirely acceptable accuracy, life, and friction at minimal cost. Therefore,
they are very widely used.
However, there are many applications where a more suitable bearing can
improve efficiency, accuracy, service intervals, reliability, speed of operation,
size, weight, and costs of purchasing and operating machinery.
Thus, there are many types of bearings, with varying shape, material,
lubrication, principle of operation, and so on.
37. AUTOMATIC GLASS PRINTING MACHINE Page 37
A rolling-element bearing, also known as a rolling bearing,[1]
is a bearing which
carries a load by placing rolling elements (such as balls or rollers) between two
bearing rings. The relative motion of the pieces causes the round elements to
roll with very little rolling resistance and with little sliding.
One of the earliest and best-known rolling-element bearings are sets of logs laid
on the ground with a large stone block on top. As the stone is pulled, the logs
roll along the ground with little sliding friction. As each log comes out the back,
it is moved to the front where the block then rolls on to it. It is possible to
imitate such a bearing by placing several pens or pencils on a table and placing
an item on top of them. See "bearings" for more on the historical development
of bearings.
A rolling element rotary bearing uses a shaft in a much larger hole, and
cylinders called "rollers" tightly fill the space between the shaft and hole. As the
shaft turns, each roller acts as the logs in the above example. However, since the
bearing is round, the rollers never fall out from under the load.
Rolling-element bearings have the advantage of a good tradeoff between cost,
size, weight, carrying capacity, durability, accuracy, friction, and so on. Other
bearing designs are often better on one specific attribute, but worse in most
other attributes, although fluid bearings can sometimes simultaneously
outperform on carrying capacity, durability, accuracy, friction, rotation rate and
sometimes cost. Only plain bearings are used as widely as rolling-element
bearings.
38. AUTOMATIC GLASS PRINTING MACHINE Page 38
MATERIAL USED IN MACHINE
CAST IRON
INTRODUCTION
Cast iron is iron or a ferrous alloy which has been heated until it liquefies, and
is then poured into a mould to solidify. It is usually made from pig iron. The
alloy constituents affect its colour when fractured: white cast iron has carbide
impurities which allow cracks to pass straight through. Grey cast iron has
graphitic flakes which deflect a passing crack and initiate countless new cracks
as the material breaks.
Carbon (C) and silicon (Si) are the main alloying elements, with the amount
ranging from 2.1–4 wt% and 1–3 wt%, respectively. Iron alloys with less
carbon content are known as steel. While this technically makes these base
alloys ternary Fe–C–Si alloys, the principle of cast iron solidification is
understood from the binary iron–carbon phase diagram. Since the compositions
of most cast irons are around the eutectic point of the iron–carbon system, the
melting temperatures closely correlate, usually ranging from 1,150 to 1,200 °C
(2,100 to 2,190 °F), which is about 300 °C (572 °F) lower than the melting
point of pure iron.
Cast iron tends to be brittle, except for malleable cast irons. With its relatively
low melting point, good fluidity, castability, excellent machinability, resistance
to deformation and wear resistance, cast irons have become an engineering
material with a wide range of applications and are used in pipes, machines and
automotive industry parts, such as cylinder heads (declining usage), cylinder
blocks and gearbox cases (declining usage). It is resistant to destruction and
weakening by oxidation (rust).
The earliest cast iron artifacts date to the 5th century BC, and were discovered
by archaeologists in what is now modern Luhe County, Jiangsu in China. Cast
iron was used in ancient China for warfare, agriculture, and architecture.[1]
During the 15th century, cast iron became utilized for artillery in Burgundy,
France, and in England during the Reformation.[2]
The first cast iron bridge was
built during the 1770s by Abraham Darby III, and is known as The Iron Bridge.
Cast iron is also used in the construction of buildings
39. AUTOMATIC GLASS PRINTING MACHINE Page 39
MILD STEEL
INTRODUCTION
Carbon steel is steel in which the main interstitial alloying constituent is carbon
in the range of 0.12–2.0%. The American Iron and Steel Institute (AISI) defines
carbon steel as the following: "Steel is considered to be carbon steel when no
minimum content is specified or required for chromium, cobalt, molybdenum,
nickel, niobium, titanium, tungsten, vanadium or zirconium, or any other
element to be added to obtain a desired alloying effect; when the specified
minimum for copper does not exceed 0.40 percent; or when the maximum
content specified for any of the following elements does not exceed the
percentages noted: manganese 1.65, silicon 0.60, copper 0.60."[1]
The term "carbon steel" may also be used in reference to steel which is not
stainless steel; in this use carbon steel may include alloy steels.
As the carbon percentage content rises, steel has the ability to become harder
and stronger through heat treating; however it becomes less ductile. Regardless
of the heat treatment, a higher carbon content reduces weldability. In carbon
steels, the higher carbon content lowers the melting point.[2]
Mild steel, also known as plain-carbon steel, is the most common form of steel
because its price is relatively low while it provides material properties that are
acceptable for many applications, more so than iron. Low-carbon steel contains
approximately 0.05–0.3% carbon[1]
making it malleable and ductile. Mild steel
has a relatively low tensile strength, but it is cheap and malleable; surface
hardness can be increased through carburizing.[3]
It is often used when large quantities of steel are needed, for example as
structural steel. The density of mild steel is approximately 7.85 g/cm3
(7850 kg/m3
or 0.284 lb/in3
)[4]
and the Young's modulus is 210 GPa
(30,000,000 psi).[5]
Low-carbon steels suffer from yield-point runout where the material has two
yield points. The first yield point (or upper yield point) is higher than the second
and the yield drops dramatically after the upper yield point. If a low-carbon
steel is only stressed to some point between the upper and lower yield point then
the surface may develop Lüder bands.[6]
Low-carbon steels contain less carbon
than other steels and are easier to cold-form, making them easier to handle.
40. AUTOMATIC GLASS PRINTING MACHINE Page 40
APPENDIX
Course Thread Sizes
Tap (Thread) Size Drill Size(mm)
M1 x 0.25 0.75
M1.1 x 0.25 0.85
M1.2 x 0.25 0.95
M1.4 x 0.3 1.10
M1.6 x 0.35 1.25
M1.8 x 0.35 1.45
M2 x 0.4 1.60
M2.2 x 0.45 1.75
M2.5 x 0.45 2.05
M3 x 0.5 2.50
M3.5 x 0.6 2.90
M4 x 0.7 3.30
M4.5 x 0.75 3.70
M5 x 0.8 4.20
M6 x 1 5.00
M7 x 1 6.00
M8 x 1.25 6.80
M9 x 1.25 7.80
M10 x 1.5 8.50
M11 x 1.5 9.50
M12 x 1.75 10.20
M14 x 2 12.00
M16 x 2 14.00
M18 x 2.5 15.50
M20 x 2.5 17.50
M22 x 2.5 19.50
M24 x 3 21.00
M27 x 3 24.00
M30 x 3.5 26.50
M33 x 3.5 29.50
M36 x 4 32.00
M39 x 4 35.00
M42 x 4.5 37.50
M45 x 4.5 40.50
M48 x 5 43.00
M52 x 5 47.00
M56 x 5.5 50.50
M60 x 5.5 54.50
M64 x 6 58.00
M68 x 6 62.00
41. AUTOMATIC GLASS PRINTING MACHINE Page 41
Fine Thread Sizes
Tap (Thread) Size Drill Size(mm)
M4 x 0.35 3.60
M4 x 0.5 3.50
M5 x 0.5 4.50
M6 x .5 5.50
M6 x .75 5.25
M7 x .75 6.25
M8 x .5 7.00
M8 x .75 7.25
M8 x 1 7.50
M9 x 1 8.00
M10 x 0.75 9.25
M10 x 1 9.0
M10 x 1.25 8.8
M11 x 1 10.0
M12 x .75 11.25
M12 x 1 11.0
M12 x 1.5 10.5
M14 x 1 13.0
M14 x 1.25 12.8
M14 x 1.5 12.5
M16 x 1 15.0
M16 x 1.5 15.0
M18 x 1 17.0
M18 x 2 16.0
M20 x 1 19.0
M20 x 1.5 18.5
M20 x 2 18.0
M22 x 1 21.0
M22 x 1.5 20.5
M22 x 2 20.0
M24 x 1.5 22.5
M24 x 2 22.0
M26 x 1.5 24.5
M27 x 1.5 25.5
M27 x 2 25.0
M28 x 1.5 26.5
M30 x 1.5 28.5
M30 x 2 28.0
M33 x 2 31.0
M36 x 3 36.0
