Electron Beam Machining Process Parameter, working Principle, Advantages, limitations, applications

1. Electron Beam Machining
J. Hemwani. GPC, Betul

2. EBM ---Working Principle
▪Workpiece placed in vacuum chamber
▪ High-voltage electron beam directed toward workpiece
▪ Energy of electron beam melts/ vaporizes selected
region of workpiece
▪ Electron beam moved by deflection coils
J. Hemwani. GPC, Betul

3. J. Hemwani. GPC, Betul

4. J. Hemwani. GPC, Betul

5. EBM – PROCESS
▪ Electron beam (negatively charged particles) is generated
in an electron beam gun.
▪The workpiece to be machined is located under the
electron beam and is kept under vacuum.
▪ Electron beam gun provides high velocity electrons over
a very small spot size.
▪ Due to pattern of electrostatic field produced by grid cup,
electrons are focused and made to flow in the form of a
converging beam through anode.
J. Hemwani. GPC, Betul

6. EBM – PROCESS
▪The electrons are accelerated while passing through the
anode by applying high voltage at anode.
▪ A magnetic deflection coil is used to make electron
beam circular and to focus electron beam at a point , this
results in localized heating.
▪ The high-energy focused electron beam is made to
impinge on the work piece with a spot size of 10 – 100
μm • The kinetic energy of the electrons, upon striking the
workpiece, changes to heat, which melts and vaporizes
minute amounts of the material.
J. Hemwani. GPC, Betul

7. EBM – ADVANTAGES
✓ • Extremely close tolerances can be maintained
✓ • Heat affected zone are minimum
✓ • It can machine almost any material irrespective of their
mechanical properties
✓ • The beam can be concentrated on a very small area
✓ • It produces better surface finish and narrow kerf
✓ • Thermal distortion is least
✓ • The process is fast because it is entirely non-
mechanical.
J. Hemwani. GPC, Betul

8. EBM – LIMITATIONS
▪ The equipment cost is very high because of vaccume
maintained.
▪ The interaction of the electron beam with work piece
surface produces hazardous X-ray. Hence shielding is
necessary.
▪ Because of very low material removal rate, the process is
economical only for small Material Removal .
▪ Skilled labour is required to operate the machine (Gun).
▪ The process can machine only thinner parts.
J. Hemwani. GPC, Betul

9. EBM – APPLICATIONS
➢ EBM is particularly suitable for micro-machining i.e.
producing very small diameter holes – down to 0.002 in.
➢Major applications of EBM include Machining of wire
drawing dies having small cross sectional area.
➢ EBM is also used as an alternative to light optics
manufacturing methods in the semiconductor industry.
➢EBM is useful for high-resolution lithography and for the
manufacture of complex integrated circuits.
➢EBM welding is also used for aircraft engine parts.
J. Hemwani. GPC, Betul

10. EBM CHARACTERISTICS
❖• Mechanics of material removal – melting, vaporization
❖• Medium – vacuum
❖• Tool – beam of electrons moving at very high velocity
❖• Maximum MRR = 10 mm3 /min
❖• Specific power consumption = 450 W/mm3 /min
❖•Critical parameters – accelerating voltage, beam diameter, work
speed, melting temperature
❖• Materials application – all materials
❖•Shape application – drilling fine holes, cutting contours in sheets,
cutting narrow slots
❖• Limitations – very high specific energy consumption, necessity of
vacuum, expensive machine
J. Hemwani. GPC, Betul

11. J. Hemwani. GPC, Betul