This document discusses electron beam micromachining (EBM), which uses a focused beam of high-velocity electrons to remove material from a workpiece through melting and vaporization. It describes the mechanism of material removal in EBM, where an electron beam generates a stream of electrons that heat the workpiece surface intensely. EBM can drill small holes, cut contours and slots, and is used in industries like aerospace, medical, and electronics. Some advantages are its ability to machine both conductive and non-conductive materials with no contact and very low tool wear. However, it requires vacuum and has high costs.

1. Electron Beam Micromachining
Supervisor:-
Prof. Vinod Yadava
Mechanical Department
MNNIT Allahabad
Presented By:-
Anurag Chaudhary
Bhaskar Singh

2. Content:
 Micromachining
 Electron Beam Micromachining
 Mechanism Of Material Removal In EBMM
 Electron Beam Drilling
 Performance Characteristics of EBD
 Process Parameters Of EBMM
 Applications, Merits and Demerits

3. Micromachining
Micro
Machining
Micromachining
Macro component but removal of material at micro/nano level.
Micro/nano components and material removal is at micro level.
Dimensions produced between greater than or equal to1μm and
smaller than or equal to 999μm[1].

4. Micromachining processes can be classified into three sub-
categories:
1. Mechanical Micromachining -Use of Mechanical Force
2. Thermal Micromachining – Use Direct Energy
3. Chemical and Electrochemical Micromachining – Uses
Chemical Reaction

5. Electron Beam Micromachining
 It is a type of thermal micromachining processes.
 It uses a high-velocity stream of electrons focused on the
workpiece surface to remove material by melting and
vaporization.
Fig:- Variation in Power density with spot diameter of Thermal
Beam Process[3]

6. Mechanism Of Material Removal In EBMM[1]
 An electron beam gun generates a continuous stream of
electrons.
 This stream of electrons is then forced through a valve that
controls the beam.
 After passing through valve, the beam is then focused onto
the surface of the workpiece.
 The kinetic energy of electrons, transferred to the work
material, produces intense heating.
 By this heat material is removed and vaporized.

7. Fig:- Schematic Of Electron Micromachining

8. Electron Beam Drilling
 CNC-EBM machine controls the main drilling parameters
and the axial movements of the workpiece and beam.
Fig:- Electron Beam Drilling Process[4]

9. Performance Characteristics of EBD[3]
Material Work-
piece
thicknes
s (mm)
Hole
dia.
(μm)
Drilling
Time
(sec)
Accele-
rating
voltage
(kV)
Beam
Current
(μA)
Tungsten 0.25 25 <1 140 50
Stainless
steel
2.5 125 10 140 100
Aluminiu
m
2.5 125 10 140 100
Alumina 0.75 300 30 125 60
Quartz 3.0 25 <1 140 10

10. Process Parameters Of EBMM[2]

11. Imortance of Vacuum
 The need of a vacuum for the EBMM process is that air
molecules can adversely interact with the beam of
electrons.
 Collision between an electron and an air molecule causes
the electron to veer.
Conduction Losses
 Conduction of heat away from the irradiated spot causes
loss of efficiency in the heating process.
Effect of Cutting Speed
 To minimize the thermal diffusion problem it is
recommended to pulse the beam or scan it rapidly across the
surface to be machined[1].

12. Material Removal rate (MRR)
Where, η= Cutting efficiency
P= Power (J/s)
W= specific energy (J/cm3)
Where, =Specific heat
=Melting Temperature
=Initial Temperature
=Boiling Temperature
=Latent heat of fusion
=Latent heat of vaporization

13. Application:-
 Machining of titanium aircraft engine parts.
 Drilling fine holes (less than 50 μm)
 Cutting contours in sheets
 Cutting narrow slots (25μm)
 Medical and electronics industries
 EBMM does not apply any cutting force on the workpieces.

14. Merits:-
 Both electrically conducting as well as non con ducting
material are machined.
 No limitation is imposed by workpiece hardness, ductility,
and surface reflectivity.
 No mechanical distortion occurs to the workpiece since
there is no contact.
 Drilling of holes with very high aspect ratio (25:1).
 Single step process.
 Very low tool wear
Demerits:-
 Need of vacuum chamber that limits the work size.
 High initial investment and high operating cost.
 Limited to thin parts in the range from 0.2 to 6 mm thick[1].

15. Bibliography
1) Introduction to Micromachining by V.K.Jain .
2) Advanced Machining Process by Hassan El-Hofy.
3) Manufacturing Science by Ghosh and Mallik.
4) Karl-Heinz Leith, Holger Koch, Michael Schmidt,
“Numerical Simulation of Drilling With Pulsed Beam”
5) EBOPULS electron beam drilling system technical
brochure, Steigerwald Strahltechnik GmbH 2006.