ELECTRON BEAM MACHINING PROCESS (EBM): Construction and Working of electron beam machining process.

Summary

Electron 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

00:00

🔨 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.

05:02

🛠 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.

Keywords

💡Electron Beam Machining (EBM)

Electron Beam Machining (EBM) is a non-conventional machining process used to machine very hard and brittle materials. This process converts the kinetic energy of electrons into heat energy by directing fast-moving electrons onto the workpiece surface, causing it to evaporate. The video focuses on explaining this process, its applications, and its advantages and disadvantages.

💡Kinetic Energy

Kinetic energy in EBM refers to the energy possessed by the high-speed electrons as they move. This energy is crucial in the machining process as it gets converted into heat energy upon impact with the workpiece, facilitating the machining of hard materials by vaporizing them. The principle is similar to laser beam machining but uses electrons instead of laser beams.

💡Heat Energy

Heat energy in EBM is generated when the kinetic energy of high-speed electrons is converted upon impact with the workpiece surface. This heat is essential for evaporating the material at the workpiece interface, allowing precise machining. The conversion of kinetic to heat energy is the core principle behind the EBM process.

💡Vacuum Chamber

A vacuum chamber is used in EBM to prevent the electrons from colliding with air particles, which would otherwise cause energy loss. The entire EBM process is carried out in this vacuum environment to maintain the electrons' high speed and ensure effective machining. This setup is necessary for achieving the precision and effectiveness of EBM.

💡Electron Gun

The electron gun in EBM is a component similar to a cathode ray tube that generates and accelerates electrons. It focuses the high-speed electrons onto the workpiece. The electron gun includes a tungsten cathode filament, which emits electrons when heated, and an anode to accelerate them. This focused beam is crucial for the precision of the EBM process.

💡Magnetic Lenses

Magnetic lenses are used in EBM to control and focus the beam of electrons. These lenses reduce the divergence of the emitted electrons, ensuring that only a convergent beam passes through to the workpiece. This focused beam is necessary to achieve high-quality machining and precise control over the machining process.

💡Thermionic Reaction

A thermionic reaction in EBM refers to the emission of electrons from the tungsten cathode filament when it is heated to about 2500 degrees Celsius. This reaction is essential for generating the electrons needed for the machining process. The thermionic emission process is a key aspect of the electron gun's operation.

💡Micro Machining

Micro machining refers to the machining of very small and precise features on materials. In EBM, it is used for operations like drilling, perforating, slotting, and scribing on thin materials. The precision of EBM makes it particularly suitable for such applications, especially in industries requiring fine details, like electronics and aerospace.

💡Metal Removal Rate (MRR)

Metal Removal Rate (MRR) in EBM is the rate at which material is removed from the workpiece. The MRR is relatively low in EBM compared to conventional machining methods. Despite this, EBM's ability to machine hard and brittle materials with high precision makes it valuable for specific applications where material removal rate is less critical.

💡High Melting Point Materials

High melting point materials are substances that require very high temperatures to melt. EBM is particularly useful for machining these materials because the process can generate the necessary heat to vaporize them. This capability makes EBM suitable for applications in industries such as aerospace and nuclear reactors, where high melting point materials are common.

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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