ELECTRON BEAM MACHINING (EBM) UNIT-6

ELECTRON BEAM MACHINING (EBM) UNIT-6

ELECTRON BEAM MACHINING (EBM) UNIT-6

Introducation:

EBM (Electron beam machining) process was invented by K.H steigerwald in Germany in 1952. EBM is a thermal metal removal process, which makes use of a focused beam of high velocity electrons for drilling, cutting, welding.

In EBM process, the high velocity focused beam of electrons are used to remove the metal from the workpiece. These electrons are travelling at half the velocity of light or 2/3 of velocity of light i.e., 1.6×108 m/sec. this process best suitable for micro cutting of material.

Electron beam is generated in an electron beam gun. The construction and working principle of the electron beam gun would be discussed in the below. Electron beam gun provides high velocity electrons over a very small spot size. Electron Beam Machining is required to be carried out in vacuum. Otherwise the electrons would interact with the air molecules, thus they would loose their energy and cutting ability. Thus the workpiece to be machined is located under the electron beam and is kept under vacuum. The high-energy focused electron beam is made to impinge on the workpiece with a spot size of 10 – 100 μm. The kinetic energy of the high velocity electrons is converted to heat energy as the electrons strike the work material. Due to high power density instant melting and vaporisation starts and “melt – vaporisation” front gradually progresses, as shown in Fig.

Working Principle :

when the high velocity beam of electrons strikes the workpiece, their kinetic energy is converted into heat energy. This concentrated heat raises the temperature of work piece material and vaporizes a small amount of it, resulting in the removal of material from the work piece.

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