Electron Beam Machining (EBM) – Advantages and Disadvantages

Electron beam machining is a thermal process used for the metal removal during the machining process. In the electrical beam machining, electrical energy is used to generate the electrons with high energy.

Working Principle of Electron Beam machining 

In the electron beam gun the electric beam is generated. Electron beam consists of a small spot size, from which it provides the high velocity electrons. The electron beam machining process is carried out in the vacuum. This is due to the electrons present in the process react with the air molecules so they lose the energy and ability of cutting. The work piece material must be placed under the electron beam, and where the equipment is placed under the vacuum. With the spot size of 10 to 100 , the high energy absorbed electron beam is ready to show impact on the work piece material. The high velocity electron consists of kinetic energy, the energy is converted into the heat energy, where the electrons strikes the work material. Because of the high energy present in the electrons it starts to melting and vaporization of the work piece material. The process is done from top to the bottom of the work piece material. In the electrical beam machining the gun is used in the pulsed mode. By using the single pulse holes, and is drilled on the thin sheets. Multiple passes are required for the thicker plates.

Electron beam machining Diagram
Electron beam machining Diagram

Advantages

  • Very hard, heat resistant materials could be machined or welded easily
  • No physical or metallurgical damage results in the workpiece.
  • Close dimensional tolerance could be achieved since there is no cutting tool wear.
  • In electron beam welding there is virtually no contamination and close control of penetration is possible.
  • Holes as small as 0.002 mm diameter could be drilled.

Disadvantages

  • The equipment costs high and operator of high skill is required for carrying out operations.
  • The power consumption is exceedingly high
  • It is not very suitable for sinking deep holes, if the sides must be parallel. In other words, it is not possible to have perfectly cylindrical
  • deep holes by this method.
  • Unless special care is taken the bottom of a thorough hole would become cone-shaped.
  • It is most suitable for machining operation where much less material is to be removed. The material removal rate being of the order of a fraction of a milligram per sec.
  • The electron beam operation can be carried out only in vacuum.

Applications

  • It is used for drilling synthetic jewels in the watch industry.
  • Holes as small as 0.002 mm diameter can be produced in hard synthetic sapphires.
  • Electron beam can be suitably used for welding small pieces of highly reactive and refractory metals.
  • For making fine gas orifices in space nuclear reactors and turbine blades for supersonic aero engines, it is used
  • Wire drawing dies, flow orifices could be produced by this process.
  • Fine copper wire can be welded to in transistors.
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