12-06-2014, 11:22 AM
DESIGN AND FABRICATION OF PNEUMATIC AUTO FEED DRILLING MACHINER EPORT
DESIGN AND FABRICATION.pdf (Size: 204.43 KB / Downloads: 38)
ABSTRACT
In small-scale industries and automobile maintenance shops, there are frequent needs of
tightening and loosening of screws, drilling, boring, grinding machine. Huge and complicated
designed parts cannot be machined with the help of an ordinary machine and further for every
operation separate machine is required therefore increasing the number of machines required and
increasing the area required for them to be accommodated and hence overall initial cost required
is increased.
In a single machine all the above specified operation can be carried out, i.e., after drilling,
the drill head is removed from the barrel key and the required tools like grinding wheels, boring
tool etc., can be attached, and the operation can be performed.
By the application of pneumatics, the pneumatic cylinder with piston which is operated
by an air compressor will give the successive action to operate this machine. By this we can
achieve our industrial requirements.
INTRODUCTION
The main objective of our project is to perform various machining operations using
“Auto feed mechanism” in drilling machine with the help of pneumatic sources. For a
developing industry the operation performed and the parts (or) components produced should
have it minimum possible production cost for it to run profitability.
In small-scale industries and automobile maintenance shops, there are frequent needs of
tightening and loosening of screws, drilling, boring, grinding machine. Huge and complicated
designed parts cannot be machined with the help of an ordinary machine and further for every
operation separate machine is required therefore increasing the number of machines required and
increasing the area required for them to be accommodated and hence overall initial cost required.
In our project the above complicated problems are minimized.
NEED FOR AUTOMATION:
Automation can be achieved through computers, hydraulics, pneumatics, robotics, etc., of
these sources, pneumatics form an attractive medium for low cost automation.
The main advantage of a pneumatic system is that it is economical and simple in construction
which makes it different from other sources of automation.
Automation plays an important role in mass production. Nowadays almost all the
manufacturing process is changing to automated machines in order to deliver the products with
better quality and at a faster rate. The manufacturing operation is being automated for the
following reasons.
To achieve mass production
To reduce man power
To increase the efficiency of the plant
To reduce the work load
To reduce the production cost
To reduce the production time
To reduce the material handling
To reduce the fatigue of workers
To achieve good product quality
Less Maintenance
LITERATURE SURVEY
PNEUMATICS:
The word ‘pneuma’ comes from Greek and means breather wind. The word pneumatics is
the study of air movement and its phenomena is derived from the word pneuma. Today
pneumatics is mainly understood to means the application of air as a working medium in
industry especially in driving and controlling of machines and equipment.
Pneumatics has been considered to be used to carry out simple mechanical tasks. But, in
today’s world it is playing an important role by becoming one of the major sources for
automation, and the recent developments in this field has made it a useful technology in the field
of complex automated applications.
Pneumatic systems operate on a supply of compressed air which must be available in
sufficient quantity and at a pressure to suit the capacity of the system. When the pneumatic
system is being adopted for the first time, however it will indeed be necessary to deal with the
section of compressed air supply.
The key part of any pneumatic machine is supply of compressed air is by means
reciprocating compressor. A compressor is a machine that takes in air, gas at a certain pressure
and delivers the air at a high pressure.
Compressor capacity is the actual quantity of air compressed and delivered. And the
volume expressed is that of the air at intake conditions namely at atmosphere pressure and
normal ambient temperature.
The compressibility of the air was first investigated by Robert Boyle in 1962 and found
that the product of pressure and volume of a particular quantity of gas is constant.
This is usually written as:
SELECTION OF PNEUMATICS:
Mechanization is broadly defined as the replacement of manual effort by mechanical
power. Pneumatic is an attractive medium for low cost mechanizations particularly for sequential
(or) repetitive operations. Many factories and plants already have a compressed air system,
which is capable of providing the power (or) energy requirements and the control system
(although equally pneumatic control systems may be economic and can be advantageously
applied to other forms of power).
The main advantage of a pneumatic system is it is economically cheap and simple in
design, also reducing maintenance costs. It can also have an out standing advantage in terms of
safety.
PNEUMATIC POWER
Pneumatic systems use pressurised gas to transmit and control power. Pneumatic
systems typically use air as the fluid medium because air is safe, free and readily available.
The Advantages of Pneumatics:
1. Air used in pneumatic systems can be directly exhausted in to the surrounding
environment and hence the need of special reservoirs and no-leak system designs
are eliminated.
2. Pneumatic systems are simple in design and economical.
3. Control of pneumatic systems is easier.
The Disadvantages of Pneumatics:
1. Pneumatic systems exhibit spongy characteristics due to compressibility of air.
PRODUCTION OF COMPRESSED AIR
Pneumatic systems operate on a supply of compressed air, which must be made available
in sufficient quantity and at a pressure to suit the capacity of the system.
The key part of any pneumatic system for supply of compressed air is by means using
reciprocating compressor. A compressor is a machine that takes in air, gas at a certain pressure
and delivers it at a higher pressure. Compressor capacity is the actual quantity of air compressed
and delivered. And the volume expressed is that of the air at intake conditions namely at
atmosphere pressure and normal ambient temperature.
Clean condition of the suction air is one of the factors, which decides the life of a
compressor. Warm and moist suction air will result in increased precipitation of condense from
the compressed air. Compressor may be classified in two general types.
1. Positive displacement compressor.
2. Turbo compressor
Positive displacement compressors are most frequently employed for compressed air
plant and have proved highly successful for pneumatic control application.
The different types of positive compressors are:
1. Reciprocating type compressor
2. Rotary type compressor
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Turbo compressors are employed where large capacity of air required at low discharge
pressures. They cannot attain pressure necessary for pneumatic control application unless built in
multistage designs and are seldom encountered in pneumatic service.
DESCRIPTION OF EQUIPMENT
3.1 PNEUMATIC CONTROL COMPONENT
3.1.1 Pneumatic cylinder
An air cylinder is an operative device in which the state input energy of compressed air
i.e. pneumatic power is converted in to mechanical output power, by reducing the pressure of the
air to that of the atmosphere.
3.1.1 a) Single acting cylinder
Single acting cylinder is only capable of performing an operating medium in only
one direction. Single acting cylinders are equipped with one inlet for the operating air pressure,
and can be produced in several designs. Single cylinders develop power in one direction only.
Therefore no heavy control equipment should be attached to them, which is required to
be moved on the piston return stoke. Single action cylinder requires only about half the air
volume consumed by a double acting for one operating cycle.
3.1.1 b) Double acting cylinders:
A double acting cylinder is employed in control systems with the full pneumatic
cushioning and it is essential when the cylinder itself is required to retard heavy loads. This can
only be done at the end positions of the piston stock. In all intermediate positions a separate
externally mounted cushioning device must be provided with the damping feature.
The normal escape of air is out off by a cushioning piston before the end of the stock is
required. As a result the sit in the cushioning chamber is again compressed since it cannot escape
but slowly according to the setting made on reverses.
The air freely enters the cylinder and the piston stokes in the other direction at full force
and velocity.
VALVES
Solenoid Valve:
The directional valve is one of the important parts of a pneumatic system. Commonly
known as DCV, this valve is used to control the direction of air flow in the pneumatic system.
The directional valve does this by changing the position of its internal movable parts.
This valve was selected for speedy operation and to reduce the manual effort and also for the
modification of the machine into automatic machine by means of using a solenoid valve.
A solenoid is an electrical device that converts electrical energy into straight line motion
and force. These are also used to operate a mechanical operation which in turn operates the
valve mechanism. Solenoids may be push type or pull type. The push type solenoid is one in
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which the plunger is pushed when the solenoid is energized electrically. The pull type solenoid
is one is which the plunger is pulled when the solenoid is energized.