The pneumatic system has gained a large amount of importance in last few decades. This importance is due to its accuracy and cost. This convenience in operating the pneumatic system has made us to design and fabricate this unit as our project. This unit, as we hope that it can be operated easily with semi skilled operators. The pneumatic press tool has an advantage of working in low pressure, that is
even a pressure of 6 bar is enough for operating the unit. The pressurized air passing through the tubes to the cylinder, forces the piston out whose power through the linkage is transmitted to the punch/rivet. The work piece thus got is for required dimensions and the piece can be collected through the land clearance provided in the die. The die used in this is fixed such that the die of required shape can be used according to the requirement.
This enables us to use different type punch dies resulting in a wide range of products. Different types of punch as requirement can be thus got. According to the work material the operating pressure can be varied.
The press is the punching and riveting machine tool designed to punch letter or rivet metal by applying mechanical force or pressure. The metal is punched or riveted to the desired requirement. The presses are exclusively intended for mass production and they represent the fastest and more efficient way to form a metal into a finished punched or riveted product. Press tools are used to form and cut thin metals. Press tools operation can be simplified to a few simple operations involving a punch a die. INTRODUCTION
There are Nemours types of presses in engineering field, which are used to fulfill the requirements. We are interested to introduce pneumatic system in presses. The main function of pneumatic press is to form or cut thin sheet metals or non metals using pneumatic power. In this project we have used to punching process and riveting process for simple application.
The compressed air from the compressor at the pressure of 5 to 7bar is passed through a pipe connected to the Solenoid valve with one input. The Solenoid Valve is actuated with Control Timing Unit. The Solenoid valve has two outputs and one input. The air entering into the input goes out through the two outputs when the timing control unit is actuated. Due to the high air pressure at the bottom of the piston, the air pressure below the piston is more than the pressure above the piston. So these moves the piston rod upwards which move up the effort are, which is pivoted by control unit. This force acting is passed on to punch/rivet which also moves downwards.
The punch/rivet is guided by a punch/rivet guide who is fixed such that the punch/rivet is clearly guided to the die. The materials are in between the punch/rivet and die. So as the punch/rivet comes down the materials are sheared to the required profile of the punch/rivet and the blank is moved downwards through the die clearance. When the piston is at the extreme point of the stock length, the exhaust valve is opened and the air is exhausted through it and the pressurized air come in at the top of the piston and it pushes the piston downwards. So the one side of the air is pulled downwards and the other side is lifted upwards. So the punch/rivet is therefore pulled upwards from the die.
Now the piston reaches the bottom point of the required stroke length. Now the material is fed and the next stroke of the piston is made ready. When the material is correctly positioned then this machine is again actuated automatically. The time duration of the succeeding punching is adjusted with the help of control timing unit.
ADVANTAGES AND APPLICATIONS
1. The outstanding advantage of pneumatic system is the control valve which consistently applies a specified load with minimum effort.
2. From thin foils to metal sheets can be pierced according to desirable shapes.
3. It can be modified to any extend to bring out the required effort.
4. Its outcome can be utilized properly in the extensive mechanical field.
5. Multiple cylinder systems can be put into action according to the need of pressing effort.
6. In modern payer plants this pneumatic system can be used for loading press roll.
7. Simple construction than the mechanical and hydraulic presses.
8. Compared to hydraulic and mechanical presses pneumatic press is economical.
9. It does not require current carrying cables.
10. No extra skill is required for operating this system.
11. Operation is very smooth and in this system we can get more output by applying less effort.
12. This system can be effectively used for punch mark in industrial materials such as industries name, address or number of product.
Hard and thick materials can not be riveted.
Even a bit of leakage may result in power loss.
Due to the linkages there will be frictional losses.
Maintenance will be more due to the number of moving parts.