Pneumatic sheet cutter

INTRODUCTION:

We are using scissors fro simple sheet metal cutting. It is a manual method so that sheet metals are to be wasted sometime because of mistakes happened such as wring dimensions and also even as simple cutting may take long time. Hydraulic machines are also available for sheet metal cutting. But this method is used only for heavy metal cutting and its cost is very high. We are using a pneumatic system for sheet metal cutting in a easy way. It is operated by a pneumatic hand lever of two way control valve. Control valve is operated by a compressor.

Pneumatics Technology:

Pneumatics is a branch of engineering that makes use of gas or pressurized air. Pneumatic systems used extensively in industry are commonly powered by compressed air or compressed inert gases. A centrally located and electrically powered compressor powers cylinders, air motors, and other pneumatic devices. A pneumatic system controlled through manual or automatic solenoid valves is selected when it provides a lower cost, more flexible, or safer alternative to electric motors and actuators.

Pneumatics also has applications in dentistry, construction, mining, and other areas.

Gases being used in pneumatics:

Pneumatic systems in fixed installations, such as factories, use compressed air because a sustainable supply can be made by compressing atmospheric air. The air usually has moisture removed, and a small quantity of oil is added at the compressor to prevent corrosion and lubricate mechanical components. Factory-plumbed pneumatic-power users need not worry about poisonous leakage, as the gas is usually just air. Smaller or stand-alone systems can use other compressed gases that present an asphyxiation hazard, such as nitrogen—often referred to as OFN (oxygen-free nitrogen) when supplied in cylinders. Any compressed gas other than air is an asphyxiation hazard—including nitrogen, which makes up 78% of air. Compressed oxygen (approx. 21% of air) would not asphyxiate, but is not used in pneumatically-powered devices because it is a fire hazard, more expensive, and offers no performance advantage over air. Portable pneumatic tools and small vehicles, such as Robot Wars machines and other hobbyist applications are often powered by compressed carbon dioxide, because containers designed to hold it such as soda stream canisters and fire extinguishers are readily available, and the phase change between liquid and gas makes it possible to obtain a larger volume of compressed gas from a lighter container than compressed air requires. Carbon dioxide is an asphyxiate and can be a freezing hazard if vented improperly.

Advantages of pneumatics

  • Simplicity of design and control:

Machines are easily designed using standard cylinders and other components, and operate via simple on-off control.

  • Reliability:

Pneumatic systems generally have long operating lives and require little maintenance. Because gas is compressible, equipment is less subject to shock damage. Gas absorbs excessive force, whereas fluid in hydraulics directly transfers force. Compressed gas can be stored, so machines still run for a while if electrical power is lost.

  • Safety:

There is a very low chance of fire compared to hydraulic oil. Newer machines are usually overload safe.

Pneumatic logic of function:

Pneumatic logic systems are sometimes used for controlling industrial processes, consisting of primary logic units like:

  • And Units

  • Or Units

  • ‘Relay or Booster’ Units

  • Latching Units

  • ‘Timer’ Units

  • Sorter berg relay

  • Fluidized amplifiers with no moving parts other than the air itself.

Pneumatic logic is a reliable and functional control method for industrial processes. In recent years, these systems have largely been replaced by electronic control systems in new installations because of the smaller size, lower cost, greater precision, and more powerful features of digital controls. Pneumatic devices are still used where upgrade cost, or safety factors dominate.

Material Required

  • Pneumatic Cylinder

  • Solenoid Valve

  • Air compressor

  • Steel Blade

  • Metallic Stand

Working Principle:

The pneumatic machines include a table with support arms to hold the sheet, stops or guide to secure the sheet upper and lower straight -edge blades a gauging device to precisely position the sheet. The tables also include the two way directional valve. The two way directional valve is connected to the compressor. The compressor has a piston for a moveable member. The piston is connected to a crankshaft, which is in turn connected to a prime mover. At inlet and outlet ports, valves allows air to enter and exit the chamber. When the compressor is switched ON the compressor air is flow to inlet of the pneumatic cylinder.

The sheet is placed between the upper and the lower blade. The lower blade remains stationary while the upper blade is forced downward. The upper blade is slightly offset from the lower blade , approximately 5 to 10 percent of the sheet thickness. Also the upper blade is usually angled so that the cut progresses from one end to the other end, This reducing the required force.

When the pneumatic hand operated lever is moved forward, the piston starts moving in the forward direction. The upper blade which are then forced against the sheet, cutting the material, when the pneumatic hand operated lever is moved backward, the upper blade will come to the original position.

After the material is cut , adjust the pneumatic hand lever to the mid position and then the compressor is switched off.

Advantages:

  • LOW COST

  • LESS CONSUMPTION OF TIME

  • EASY TO HANDLE

  • SKILLED LABOUR IS NOT REQUIRED

  • LESS MAINTAINANCE

  • HIGH ACCURACY

  • GOOD SURFACE FINISH

  • LESS FLOOR SPACE

APPLICATIONS:

SHEET METALS are used in various places some of them are given below:

  • CAR BODIES

  • AIRPLANE WINGS

  • MEDICAL TABLES

  • ROOFS FOR BUILDINGS AND MANY OTHER THINGS

  • SHEET METAL OF IRON AND OTHER MATERIAL WITH HIGH PERMEABILITY ALSO KNOWN AS LAMINATED STEEL CORES, AHS APPLICATION IN TRANSFORMERS AND ELECTRIC MACHIES.