#machining process

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Introduction-

Want to know about Electron beam machining?

Then you landed in the right place. Here you will know the Electron beam machining process, From scratch to end.

I will cover topics like- basic definition, principle, various equipment and its construction and further working, advantages, disadvantages, application and so on.

So, stay with me while I start this knowledgeable journey with you.

So, let’s dive in...

What is Electron Beam?

The Electron Beam is a stream of negatively charged particles that are generated, accelerated, and some extent, focussed inside a device called an ” Electron Gun”.

What is Electron Beam Machining?

Electron Beam machining or EBM is a non-conventional machining process, Where the electrons are focused and concentrated on the small spot on the metal, the kinetic energy of the electrons is converted into heat energy which is sufficient to melt the workpiece, Known as Electron beam machining or EBM.

It is just similar to laser beam machining and electron beam machining is most appropriate for machine very hard and brittle materials that cannot be machined using a conventional process.

Working principle of Electron beam Machining-

EBM machining process works on the principle of the high-velocity beam of the electron is focused on the workpiece, the electrons strike on the workpiece and their kinetic energy is converted into heat energy.

This results in the removal of material from the workpiece by vaporization and melting.

Fig. Electron beam machining diagram-

Types of Electron Beam Machining-

There is two types of EBM machining process

Thermal EBM-

The Beam is used to heat the material up to the point where it is selectively vaporized.

Non-Thermal EBM-

This utilizes the beam to cause a chemical reaction.

Construction of Electron Beam Machining-

Here are some equipment and construction of EBM machining-

Electron Gun

Magnetic lens

Electronic lens

Magnetic deflection coil

Optical viewing system

Vacuum chamber

Electronic system

Movable table

Electron Gun-

Electron gun which generates and directs a controlled beam of electrons of high energy density on the workpiece to change it chemically and physically.

Magnetic Lens-

The magnetic lens is provided which shape the beam and doesn’t allow to diverge electron or reduce the divergence of the beam.

Electromagnetic lens-

An electronic lens is used to focus the electron beam at a spot.

Magnetic deflection coil-

The Magnetic deflecting coil does not allow to beam deflect and take care of all the electron movements.

Optical viewing system-

It is a system to check whether the process is under control or not.

Vacuum chamber-

EBM process is done in the vacuum chamber to avoid any air entering probability so Electron Beam Machining is required to be carried out in the vacuum. Because air can decrease the velocity of the electron beam, hence electron beam machining requires a vacuum during the entire operation.

Electronic system-

An electronic system that controls the size and movement of the beam.

Movable table-

The workpiece is mounted on the movable table fixture that is mostly operated with CNC. The table can be move in all three directions.

Working-

The EBM works the same as laser beam machining. Here electron beam machining working can be summarized into the following points-

Electron gun produces high-velocity electrons particles.

Then, This high-velocity electrons particle moves towards the Anode.

Here from the Anode, It gets concentrated and moves towards the magnetic lens.

Here in the magnetic lens, the convergent electrons pass through it and all divergent and low energy electrons are absorbed by it, resulting in high-quality electron beam production.

After passing through the magnetic lens, High-quality electrons move to the deflection coil which focuses the electron beam at the single spot point.

Hence High-intensity electron beam is ready to bombard the surface of the workpiece.

Here kinetic energy of electrons converts into thermal energy.

And due to the thermal energy, the material is removed from the contact surface by melting and vaporizing.

Introduction-

Want to know about Laser beam machining?

Then you landed in the right place. Here you will get a complete and detailed article on the laser beam machining process, from scratch to end.

What is laser?

The laser is a device for producing a very narrow beam of highly intensive monochromatic coherent light.

By the way, The word LASER basically stands for-

L→ Light

A→ Amplification by

S→ Stimulated

E→ Emission of

R→ Radiation

Laser is produced when electrons and atoms of special crystals are energize using electric current.

These excited electrons emit photons and these emitted photons from a concentrated beam of light, forming a laser.

Generally, garnet crystal is commonly used in solid-state lasers.

This laser is discovered by Dr T.H. Maiman in 1960.

Now, let’s dig into the mainstream of the article, where I will explain the laser beam machining process. So, let’s jump in-

What is Laser beam machining?

Laser beam machining(LBM) is a non-conventional process in which material is removed using the laser beam to produce heat and due to that heat, metal is removed from the surface of the workpiece, due to vaporization.

The laser beam machining process is used for machining brittle materials with low conductivity, But it can be used on almost every material.

Laser beam machining working principle-

LBM machining works on the basis of laser properties in which a laser is directed towards the workpiece for machining.

This process uses thermal energy to remove materials from metallic or non-metallic surfaces.

In this process, a monochromatic laser beam is made to focus on the workpiece to be machined by a lens to give extremely high energy density to melt and vaporize any material.

Fig.- laser beam machining diagram-

Parts of Laser beam machining-

Here are some equipment or components used in the LBM process–

Power Supply-

It provides the energy for the excitation of electrons from lower energy levels to higher energy levels.

Flash lamp-

The power supply is connected to the flash lamp to expose laser material through emitted light by the flash lamp.

Basically, the flash lamp is used to get energize the laser material.

Laser Discharge Tube-

A laser tube is used to fill laser material inside including a mirror on both sides of the tube. One side mirror is partially reflective and the other side includes totally reflective.

Laser materials-

Laser material plays a key role in this process.

where Co2(pulsed or continuous waves) and Nd: YAG is used as laser material.

Co2 emits light in the infrared region and it can provide up to 25KW power in continuous mode.

And, Neodymium Doped Yttrium Aluminium Garnet(Nd: YAG) is a solid-state laser and it can deliver light through optical fibre and it can provide 50KW in the form of Pulsed mode and 1KW in the form of continuous mode.

Lens-

A convex lens is used to focus on the workpiece. The main function of the lens is to focus the laser beam in the single-pointed direction directly on the workpiece.

Construction of Laser beam machining-

Firstly, there is the power supply as you can see in the diagram above.

And, two flash lamp has installed both sides of the laser discharge tube.

Again, two reflecting mirror is installed both sides of the laser tube on the top and bottom position.

Here, at the top of the laser tube, a 100% reflective mirror is installed and the bottom of the tube partially reflective mirror is mounted.

After the mirror, a lens is mounted to focus the laser rays on the workpiece.

Working-

Here is the working of LBM-

When the switch is turned on, a High voltage power supply applies to cross the flashlight or flash tube and the flashlight gives energy to the laser material in the laser discharge tube.

When the light is turned on laser tube emits the high energy photons and hence these high energy photons are absorbed by the laser material.

This absorbed energy causes most of the electrons contains in the atom of the laser material to be excited at the high energy level from its ground state.

After a short duration, The electrons of the high energy level comes to the ground state, they emit photons.

These emitted photons stimulate the excited electrons to returns to their ground state. Thus, producing more photons.

As the Photon concentration increases, the laser is formed.

A 100% reflective mirror is used to reflect all the photons back to the laser material and a semi-reflective mirror reflects some of the photons back and escaping photons through a semi-reflective mirror forms a high energy laser beam.

Then a lens is used to focus the laser beam on the workpiece to be machined.

Interaction of laser and workpiece produces a large amount of heat and thus vaporizing the surface of the workpiece.

And hence laser beam machining process can be used for removing materials from the workpiece through this process.

Introduction-

Want to know about Plasma Arc Machining?

Then you landed in the right place. Here you will know about the plasma arc machining process, from scratch to end.

Welcome to Engineers Rail, Grab your seat and be comfortable, while I start the engine of the knowledge.

So, let’s get started…

First, I would like to tell you about What is plasma, to clear your basics. So, here it is-

What is Plasma?

Plasma is often called the fourth state of the matter. The first three are-

Solid

Liquid

Gas

So, If you first start with solid, let’s say-Ice.

When you put energy into ice, it will start melting.

Again if you put further energy into the melted ice (Liquid), it will start to evaporate and converts into Gas.

Now, if you put even more energy into the gas, it gets ionized and this ionized gas is called Plasma.

So, Plasma is essentially an ionized gas that has some interesting properties like it conducts electricity and emits light.

Now, Let’s drive into the mainstream of the article, Starting with- What is plasma arc machining and later on working principle.

What is Plasma Arc Machining?

When gas is heated to a temperature of about 5500C to ionize the gas, when gas is completely ionized, then the temperature of the central part of the plasma is between 11000°C to 28000°C.

When such an ionized gas is directed on the workpiece through a high-velocity jet, the metal is removed by melting.

This high velocity of hot gas is known as plasma jet and this process is known as plasma arc machining(PAM).

Working Principle of Plasma arc machining-

Here is the principle of plasma arc machining-

In PAM Machining, constricting an electric arc through a nozzle generates the basic plasma jet. Instead of diverging into an open arc, the nozzle constricts the arc into a small cross-section.

This action greatly increases the power of the arc so that both temperature and voltage are raised.

After passing through the nozzle, the arc exists in the form of a high-velocity, well-illuminated and intensity hot plasma jet.

The basic heating phenomenon that takes place at the workpiece is a combination of heating due to the energy transfer of electrons

Recombination of dissociated molecules on the workpiece, and the convective heating from the high-temperature plasma that accompanies the arc.

Once the material has been raised to the molten point, the high-velocity gas stream effectively blows the material away.

Components & construction of Plasma arc machining-

Here are the plasma arc cutting equipment and construction, given below-

Power supply

Gas supply

Cooling water system

Electrode & nozzle

Workpiece

Power supply-

Electricity supply is needed to turn the gas into plasma, the greater the current, the harder the plasma.

Gas Supply-

Compressed air, nitrogen and other gas provide a source for the plasma. In this example, a second inert sealed gas is used to protect the workpiece and blow off melted metal.

Cooling water system-

A cooling water system is used to provide the cooling effect to the plasma torch, mounted in the other body of the plasma cutter.

Electrode & Nozzle-

Special engineered electrodes and nozzles constrict and maintain the plasma jet concentrating it into the small area so it can be used for cutting.

Workpiece-

The workpiece is positioned below the plasma gun in pam machining. Materials like magnesium, carbon, stainless steel, aluminium and steel alloys can be cut using this process.

Now, let’s discuss the working of the same.

Working-

When the operator is ready to cut, a start signal is sent to the DC power supply.

A circuit temporarily connects the nozzle to the positive side of the power supply with the electrode on the negative side.

Next, the high-frequency spark ionizes the gas and makes it electrically conductive.

This creates a current path between the electrode and nozzle and forms a Pilot arc plasma.

When the pilot arc contacts the workpiece, the plasma arc transfers to the workpiece melting the metal.

Then, the high-velocity gas blows the molten material away.

And that’s the end of the working of PAM.

Hence, let’s look out further the Advantages, disadvantages and applications of this process in this journey.

Advantages of plasma arc machining-

Here are some advantages of the PAM machining process-

The main advantage of PAM is the suitability for any materials irrespective of hardness or heat resistant characteristics.

PAM allows high material removal rate(up to 10000 cm3/hr) and Material removal rate(MRR) for high strength materials are comparable with conventional turning.

Ferrous and non-ferrous materials up to 150 mm thick can be cut.

Plasma arc methods are also employed in special applications to replace conventional machining operations such as lathe turning, milling and planning, heat treatment and metal deposition operation, and plasma arc welding.

The plasma arc, as an industrial tool, is the heaviest employed in sheet and plate cutting operations as an alternative to more conventional oxy-fuel torches or cutting tools.

Introduction-

Want to know about the Electrical discharge machining?

Then you landed in the right place. Here you will get complete details about the electro-discharge machining process, from scratch to end.

So, I invite you to come along the board and stay with me while I take you on the journey of knowledge, here in Engineers Rail.

So, Shall we start?

What is Electrical Discharge Machining?

Electric discharge machining is a non-conventional machining process that uses an electric spark to remove metal from the workpiece.

This process is done by applying high-frequency current through electrodes and Workpiece emerging in the dielectric fluid.

It is also known as Spark erosion, Electro-erosion or spark machining.

Electrical discharge machining(EDM) is used to machine very hard materials.

Working Principle of electrical discharge machining-

Here is the working principle of EDM machining-

EDM works on the principle of Heat energy generated by a spark is used to remove the material from the workpiece.

The tool and workpiece are separated by a small gap called a spark gap. The gap is varied from 0.01mm to 0.5mm.

When supply is ON, thousands of sparks are produced per second.

When the spark comes in the contact with the dielectric fluid in the spark gap, the fluid gets ionized. It allows current to flow between the tool and workpiece.

Types of Electrical discharge machining-

Die sinking EDM process

Wire cut EDM process

Hole drilling EDM process

Die Sinking EDM process-

When two metals parts are placed in the dielectric fluid and connected to the source power supply, erosion of material takes place due to spark energy generated by electric tension between two metals parts, ie, anode and cathode. It is also known as the sinker EDM process.

In this case, the metal removal is affected by non-stationary electrical discharges which are separated from each other both spatially and temporarily.

Wire Cut EDM Process-

The fundamental principle of metal removal in wire cut EDM is the same as EDM. It is also known as WEDM.

It employs electrical energy to remove metal from the workpiece without touching it.

The maximum depth of the workpiece is to be 90mm, wire dia is to be 0.3mm and speed should be 2.5 to 150mm/sec.

Here in WEDM wire acts as a tool and EDM wire is made of copper or a mixture of copper graphite.

Hole Drilling EDM Process-

Here in hole drill EDM, High-pressure dielectric fluid enters through the rotating electrode to produce fast and accurate drills.

hole drill EDM is just similar to die sink EDM, But there is a number of differences.

Hole drilling EDM is used to drill holes where difficult to machine materials is to drill.

To drill, different types of electrodes are used in different materials, from small as 0.3mm diameter to 6mm diameter.

After knowing the types of EDM, Now let’s move to the various parts and construction of the EDM machines.

Parts of Electric discharge machining-

Here are the principal components of the EDM process-

DC pulse generator

workpiece and tool

Servo control unit

Pinion

Dielectric Medium

Dielectric fluid

DC pulse generator-

This converts the AC power supply into a high pulse DC supply, responsible for generating spark between the tool in the workpiece.

The negative terminal sets to the tool and the positive terminal is supplied to the workpiece.

Workpiece and tool-

Here workpiece acts as Anode and the tool acts as a cathode.

Servo control unit-

A servo control unit controls the spark gap between the tool and workpiece.

Pinion-

The pinion is used to controlling the motion of the tool directed by the servo control unit

Dielectric Medium-

Dielectric medium is consist of dielectric fluid, fixture, and workpiece itself.

Dielectric fluid-

It works to maintain the gap between workpiece and tool, acting as a non-conductor. Mostly, Deionized water, silicon oil, glycol, kerosene oil is used as dielectric in ed machining.

How does it work?

Here is a working explanation of electric discharge machining, step by step-

As the pulse of DC electricity reaches the electrode and applies an intense electrical field develops in the gap.

Microscopic contaminants suspended in the dielectric fluid are attracted by the field contrasted in the field’s strongest point.

These contaminants build a high conductive bridge across the gap.

As the field’s voltage increases, the material of the conductive bridge heats up.

Some pieces are ionized to form a spark channel between the electrode and the workpiece.

At this point, Both the temperature and pressure in the channel rapidly increase, generating a spark.

A small amount of material is melt and vaporized from the electrode and the workpiece at the point of spark contact.

Hence, metal removal in electric discharge machining takes place through Spark erosion.

Abrasive Jet Machining Definition-

Abrasive jet machining(AJM) uses a stream of fine-grained abrasive mixed with air or some other carrier gas at high pressure directed by nozzle on the work surface, where metal removal occurs due to erosion caused by the abrasive particle impacting the work surface at the high speed.

Principle-

In abrasive jet machining, the material is removed by the erosive action of a high-velocity stream of fine abrasive particles transmit on the work surface.

Parts and construction-

Here are several parts and construction of the Abrasive Jet Machining-

Air compressor

Air Filter

Pressure Gauge

Flow Regulator Valve

Mixing Chamber

Hoper

Vibrator

Nozzle

Working principle of Abrasive Jet Machining-

Step by Step guide of abrasive jet machining working-

Firstly, Air is drawn to the air compressor, where the air is pressurized in between 25-130psig.

After the compressor, pressurized air goes to the filter, Where the air is filtered from any atmospheric impurities in the air.

Now, Pressure is monitored with the help of a Pressure gauge and the next Abrasive jet flow is regulated through a regulator valve. And then, Air passes to the mixing chamber, where the abrasive particle is fed with the help of hoper to the mixing chamber.

Read in-depth working Here

Process Parameters-

The parameters that influence the rate of metal removal rate(MRR) and accuracy of the machining in this process are-

Carrier gas

Types of abrasive

Size of abrasive grain

The velocity of abrasive jet

Work material

Nozzle design

I hope you liked it.

Introduction-

There has been a rapid growth in the development of harder to machine metals and alloys during the last two decades.

Here, you will know about the Conventional and Non-Conventional machining processes and their differences.

So, grab your seat in Engineers Rail and relax, while I start the engine and take you to the Knowleable journey.

So, Let’s get started…

Before I jump to the topic of the article, It would be nice to let get an overview of these terms before. What do you say?

♦There is two types of Metal removal process–

Conventional Machining Process

Un-Conventional Machining Process

Conventional Machining Process-

As the name suggests, the Conventional Machining process is- Where the metal removing process is done manually or physically. This machining process is also known as the Traditional Machining process.

Conventional machining is uneconomical for such materials and the degree of accuracy and surface finish attainable is poor.

These are some examples of the same.

Example of Conventional machining process–

Turning

Boring

Drilling

Milling

Shaping

Sawing

Planing

Broaching

Slotting

Reaming

Grinding

Tapping

These were some examples of the Traditional machining process, Now let’s talk about some advantages of the Traditional machining process.

Advantages of Conventional Machining Process–

Here are some advantages-

The complex specimen can be machined

Easy setup

Economical

Non-Conventional Machining Process-

Non-conventional machining processes are those- where the metal removal process is done through mechanical, electrochemical, chemical, thermoelectric and without involving conventional tools. It is also known as the Modern Machining process or Un-Traditional Machining process.

Merchant(1960) emphasized the need for the development of newer concepts in metal machining. By adopting a unified programme and utilizing the result of basic and applied research.

The newer machining processes are often called ‘modern machining process’ or ‘Unconventional machining process methods’. These are unconventional in the sense that conventional tools are not employed for metal cutting, instead energy.

Example of Un-conventional machining process-

Ultrasonic Machining(USM)

Abrasive Jet Machining(AJM)

Water Jet Machining(WJM)

Electrochemical Machining(ECM)

Electrochemical Grinding(ECG)

Electrochemical Deburring(ECD)

Electrochemical Honing(ECH)

Chemical Machining(CHM)

Electric Discharge Machining(EDM)

Plasma Arc Machining(PAM)

Electron Beam Machining(EBM)

Neutral Particle Etching(NPE)

Laser Beam Machining(LBM)

Hot Machining(HM)

Classification of Un-conventional Machining Process-

The classification of modern machining processes is based on the type of energy used, the metal removal mechanism, and the source of energy requirement.

Metal Forming Process-Basics, Machining Process, Milling operations etc.

All the concepts of Metal Forming Process are presented in the Tabular Column below. Just click on the links to navigate…

Metal Forming Process

Metal Forming Process-Basics

Sheet Metal Operations:Punching, Blanking, Deep Drawing, Bending

5+Types of Dies used in Sheet Metal Operations:Simple Die,Compound, Progressive, Transfer Die

Machining Process

Drilling & Radial Drilling Machine

Grin…