ELECTRON BEAM MACHINING PROCESS (EBM): Construction and Working of electron beam machining process.
Summary
TLDRElectron Beam Machining (EBM) is a high-tech, non-conventional process for shaping hard and brittle materials. It operates by converting electron kinetic energy into heat, vaporizing material from the workpiece surface. The process requires a vacuum to prevent energy loss and utilizes advanced components like an electron gun, magnetic lenses, and a deflecting coil for precision. EBM excels in micro-machining, creating small holes, and working with materials of low thermal conductivity and high melting points. Despite its advantages, such as good surface finish and no tool wear, it has limitations, including a low metal removal rate and high equipment costs.
Takeaways
- ⚙️ Electron beam machining (EBM) is a non-conventional process for machining very hard and brittle materials.
- 💡 The process involves converting the kinetic energy of electrons into heat energy to vaporize the workpiece surface.
- 📽️ EBM is similar to laser beam machining but uses an electron beam instead of a laser.
- 🔬 EBM works on the principle of converting electron kinetic energy into heat energy when electrons impinge on the workpiece.
- ⚡ The process requires a vacuum to prevent electrons from colliding with air particles and losing energy.
- 🛠️ EBM equipment is similar to electron beam welding machines, utilizing high voltage to accelerate electrons to a significant fraction of the speed of light.
- 🔧 Key components include the electron gun, cathode filament made of tungsten, anode, magnetic lenses, deflecting coil, and workpiece holding device.
- 🔍 EBM is used for micro-machining operations like drilling, perforating, slotting, and scribing on thin materials.
- 📏 Advantages of EBM include machining very hard materials, achieving close dimensional tolerance, good surface finish, minimal heat-affected zone, and no physical contact between tool and workpiece.
- ⚠️ Disadvantages include low metal removal rate, vacuum requirement limiting workpiece size, suitability for small cuts only, and high equipment cost.
Q & A
What is Electron Beam Machining (EBM)?
-Electron Beam Machining (EBM) is a non-conventional machining process used for machining very hard and brittle materials that cannot be machined by conventional methods. It works by converting the kinetic energy of electrons into heat energy, which evaporates the workpiece surface.
How does the electron beam machining process work?
-In EBM, the kinetic energy of electrons is converted into heat energy by impinging fast-moving electrons on the workpiece surface. This heat energy vaporizes the workpiece surface, similar to laser beam machining.
Why is a vacuum necessary for EBM?
-A vacuum is required for EBM because electrons will collide with particles in the air and lose their energy if conducted in a non-vacuum environment.
What is the role of the electron gun in EBM?
-The electron gun is a cathode ray tube that generates electrons, accelerates them at a very high speed, and focuses them on the required spot on the workpiece.
What material is typically used for the cathode filament in the electron gun?
-The cathode filament is made up of tungsten, which is heated to about 2500 degrees Celsius to accelerate electron emission by thermionic reaction.
How do magnetic lenses contribute to the EBM process?
-Magnetic lenses reduce the divergence of the electron beam and allow only a convergent beam to pass to the next stage, thus obtaining a highly focused beam of electrons.
What is the purpose of the deflecting coil in EBM?
-The deflecting coil prevents the beam from deflecting, thus forming a high-intensity beam that is focused on the workpiece.
What are the typical applications of EBM?
-EBM is mainly used for micro machining operations on thin materials, such as drilling, perforating, slotting, and scribing. It is also used for making fine gas orifices in space nuclear reactors and gas turbines, and for producing very small diameter holes.
What are some advantages of using EBM?
-Advantages of EBM include the ability to machine very hard and heat-resistant materials, achieving close dimensional tolerances, producing a good surface finish, and having a minimal heat-affected zone. Additionally, there is no physical contact between the tool and the workpiece.
What are some disadvantages of EBM?
-Disadvantages of EBM include a low metal removal rate (MRR), the requirement for a vacuum which limits the size of the workpiece, the ability to only make small cuts, and the high cost of equipment.
How does EBM compare to laser beam machining in terms of process?
-Both EBM and laser beam machining involve the conversion of energy to vaporize the workpiece surface, but EBM uses a high-energy electron beam instead of a laser.
Outlines
🔨 Introduction to Electron Beam Machining (EBM)
Electron Beam Machining (EBM) is a non-conventional technique for shaping hard and brittle materials that are difficult to process with traditional methods. It operates on the principle of converting the kinetic energy of electrons into heat energy, which vaporizes the workpiece surface. This process is akin to laser beam machining but utilizes an electron beam instead of a laser. The script provides a link to learn more about laser beam machining and outlines the video's content, which includes the working principle, construction, operation, applications, advantages, and disadvantages of EBM. The process requires a vacuum to prevent electron energy loss due to air particle collisions.
🛠 Construction and Working of EBM Equipment
The construction of EBM equipment is similar to electron beam welding machines, using a power supply that accelerates electrons to nearly the speed of light through a voltage range of 50 to 200 kilo volts. The electron gun, which is a cathode ray tube, generates and accelerates electrons. A heated tungsten filament within the cathode serves as the electron source, while an anode pulls the electrons towards it. Magnetic lenses are used to focus the electron beam, and a deflecting coil ensures the beam's direction remains stable. The workpiece is held in a device that can move along the x, y, and z axes to align with the electron beam. The high-intensity electron beam is focused onto the workpiece, causing material removal through melting and vaporization due to the conversion of kinetic energy into thermal energy, all within a vacuum chamber.
🔩 Applications and Benefits of EBM
EBM finds its applications in micro-machining operations such as drilling, perforating, slotting, and scribing on thin materials. It is particularly effective for materials with low thermal conductivity and high melting points. EBM is also used for creating fine gas orifices in space and nuclear reactors, as well as in gas turbine blades and wire drawing dies. It is well-suited for producing very small diameter holes, as small as 0.002 millimeters. The advantages of EBM include the ability to machine very hard and heat-resistant materials, achieving close dimensional tolerances, producing a good surface finish, and minimizing the heat-affected zone. Additionally, there is no physical contact between the tool and the workpiece, which eliminates tool wear.
🚫 Limitations and Considerations of EBM
Despite its advantages, EBM has certain limitations. The metal removal rate (MRR) is relatively low, and the requirement for a vacuum environment restricts the size of the workpiece that can be processed. EBM is also limited to small cuts and has a high equipment cost. The script encourages viewers to subscribe to the channel for updates, like the video if they find it useful, and share it with friends for further support.
Mindmap
Keywords
💡Electron Beam Machining (EBM)
💡Kinetic Energy
💡Heat Energy
💡Vacuum Chamber
💡Electron Gun
💡Magnetic Lenses
💡Thermionic Reaction
💡Micro Machining
💡Metal Removal Rate (MRR)
💡High Melting Point Materials
Highlights
Electron Beam Machining (EBM) is a non-conventional machining process suitable for very hard and brittle materials.
EBM converts the kinetic energy of electrons into heat energy to evaporate the workpiece surface, similar to Laser Beam Machining.
The process requires a vacuum to prevent electron collision with air particles and energy loss.
Electron Beam Machines use 50 to 200 kilo volts to accelerate electrons to nearly the speed of light.
The electron gun in EBM equipment generates and accelerates electrons using a heated tungsten filament.
Magnetic lenses in the equipment focus the electron beam, reducing divergence for a highly focused output.
Deflecting coils ensure the electron beam maintains its path without deflection.
The workpiece holding device allows movement in the x, y, and z axes for precise machining.
EBM is used for micro-machining operations like drilling, perforating, slotting, and scribing on thin materials.
It is particularly useful for machining materials with low thermal conductivity and high melting points.
EBM is employed for making fine gas orifices in space nuclear reactors and gas turbine blades.
The process is ideal for creating flow orifices in wire drawing dies.
EBM is capable of producing very small diameter holes, approximately 0.002 millimeters.
One advantage of EBM is the ability to machine very hard and heat-resistant materials.
It achieves close dimensional tolerances and produces a good surface finish.
The heat-affected zone in EBM is minimal due to the precision of the process.
There is no physical contact between the tool and the workpiece, eliminating tool wear.
Disadvantages include a low metal removal rate and the limitation on workpiece size due to vacuum requirements.
EBM equipment is costly, which can be a barrier to its widespread use.
Transcripts
electron beam machining
electron beam machining or ebm is a
non-conventional machining process
used for machining of very hard and
brittle materials which otherwise cannot
be machined by conventional machining
processes
in electron beam machining process the
kinetic energy of the electron is
converted into heat energy
by impinging the fast moving electron on
the workpiece surface
this heat energy evaporates the
workpiece surface similar to the laser
beam machining process
where a laser is used in place of
electron beam
if you are interested in knowing how
laser beam machining is carried out i
have provided the link in the
description below
click on the i button to watch it and if
you are new to adtw
click on the subscribe button below this
video will cover the following about the
edm process
1. working principle 2.
construction 3. working
4. application 5. advantages and
disadvantages
working principle this machining process
works on the basic principle of
conversion of kinetic energy of
electrons into heat energy
when a high speed electron impinges on a
work piece its kinetic energy is
converted into heat energy
this heat energy is used to vaporize
material at the workpiece interface
this is the basic principle of ebm
machining this process
is carried out in the vacuum otherwise
the electrons will collide with the
particles in the air and lose its energy
construction construction of electron
beam equipment is built similar to
electron beam welding machines
power supply electron beam machines
utilize voltage in the range of 50 to
200 kilo volt
to accelerate the electron to 50 percent
to 80 percent of the speed of light
which is about 200 000 kilometers per
second
electron gun it is a cathode rate tube
which generates the electrons
accelerates them at a very high speed
and focuses on the required spot on the
workpiece
cathode filament is made up of tungsten
which is heated at about 2500 degrees
celsius
which accelerate the electron emission
by thermionic reaction
a node a node is connected to the
positive bias the electrons are pulled
towards the anode at very high speed
and therefore electrons produced by the
cathode filament are not diverged from
its
path magnetic lenses the emitted
electrons are both divergent and
convergent
the magnetic lens reduces the divergence
of the beam and allows only convergent
beam to pass to the next stage
thus a highly focused beam of electrons
is obtained
deflecting coil the deflecting coil does
not allow the beam to deflect
thus forming a high intense beam
workpiece holding device
the workpiece is held rigidly on the
workpiece holding device
which can move in all three directions
that is in the x
y and z axis working
when a high voltage supply is applied to
the cathode filament
it generates the electrons this
electrons move toward the anode at very
high velocity
after passing through the anode the beam
of electron is made to pass through
magnetic lenses where diverging and low
energy electrons are absorbed
an only converging beam of electron is
made to pass through it
thus forming high quality electron beam
then this beam passes through the
electromagnetic lens and deflecting coil
which focuses the high energy electron
beam onto the required spot of the
workpiece surface
the high intense electron beam impinges
on the workpiece where kinetic energy of
electrons convert into thermal energy
and the workpiece material is removed by
this intense heat
thereby melting and vaporizing it and
this whole process is carried out in the
vacuum chamber
application of ebm 1. dbm
is mainly used for micro machining
operations on thin materials
these operations include drilling
perforating slotting
and scribing etc 2. it is particularly
useful for machining
of materials of low thermal conductivity
and high melting point
three for making fine gas orifices in
space nuclear reactors and gas turbines
blades
four flow orifices in wire drawing dies
5. it is particularly suitable for
producing very small diameter holes
about 0.002 millimeters
advantages of ebm one very hard and heat
resistant materials can be machined
two closed dimensional tolerance can be
achieved
three produces good surface finish
four heat affected zone is minimum five
no physical contact between two and the
workpiece therefore there is no tool
where
disadvantages of ebm one
metal removal rate that is mrr is low
two vacuum requirement limits the size
of the workpiece
3. it can be used for small cuts only
4. equipment cost is high hope you have
understood electron beam machining
process
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