Laser beam machining: Definition, Working Principle, Equipments, Working, Advantages, Disadvantages

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.

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Lets’s start from scratch…

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At the end of this article, you can download this whole article as a PDF and also in the form of PPT.

Now, Let’s began…

What is a 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

A laser is produced when electrons and atoms of special crystals are energised using an 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–

1. Power Supply-

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

2. 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.

3. 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.

4. 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.

5. 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 lamps have been installed on both sides of the laser discharge tube.
• Again, two reflecting mirror is installed on both sides of the laser tube in the top and bottom position.
• Here, at the top of the laser tube, a 100% reflective mirror is installed and at 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 of Laser Beam Machining-

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 contained 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 come to the ground state, and they emit photons.
• These emitted photons stimulate the excited electrons to return 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 form a high-energy laser beam.
• Then a lens is used to focus the laser beam on the workpiece to be machined.
• The 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.

Now, let’s jump into the laser beam machining advantages, disadvantages and applications.

So, here we go…

Advantages of laser beam machining-

Here are some advantages of the LBM machining process-

• All materials cutting capacity
• No tooling cost as no tool is required
• High accuracy
• small holes can be drilled accurately
• Produces complex shapes
• Hard materials machining ability
• Process flexibility
• It can cut through air, vacuum, and even though the liquid.
• Free of mechanical force exertion on the workpiece

Disadvantages of laser beam machining-

Here are some limitations of laser beam machining–

• High capital and operating cost
• High power consumption
• Difficult to cut highly conductive and reflective materials like aluminium and copper.
• The life of the flashlight is short
• A skilled operator is required to control the process
• Low efficiency
• Low metal removal rate(MRR)
• Safety hazardous

Applications of laser beam machining-

Here are some laser beam machining applications-

• Small hole drilling
• Cutting and drilling of both metal and non-metal materials
• Electronics and automobile industries
• Aerospace industries
• Complex profile
• Welding
• Surface treatment
• Engraving
• Communication
• Entertainment

Conclusion-

Laser beam machining is a widely used machining process and is well known among various industries.

As I have shared the variety of knowledge above regarding the same,

I hope you like the knowledgeable journey of the LBM process. If so, consider, sharing with your friends and colleagues or needy ones. Sharing links are down there.

Here are some more machining processes, You would like to read about-

Plasma arc machining

Electric discharge machining

Electrochemical Machining

Water Jet Machining

Abrasive Jet Machining

Ultrasonic Machining

Difference Between Conventional and Non-Conventional Machining Processes

Thank you for being with me. I hope to see you in the next session.

 

Before you go, here is your gift-

laser beam machining pdf–

laser beam machining ppt-