Laser beam machining (LBM) is a non-conventional Machining manufacturing process, a form of machining, in which a laser is directed towards the workpiece for machining. This process uses thermal energy to remove material from metallic or nonmetallic surfaces.
The high frequency of monochromatic light will fall on the surface then heating, melting and vaporizing of the material take place due to impinge of photons. Laser beam machining is best suited for brittle materials with low conductivity, but can be used on most materials.
A form of Laser beam machining can be done on glass without melting the surface. With Photosensitive glass, the laser alters the chemical structure of the glass allowing it to be selectively etched. The glass is also referred to as photo machinable glass.
The advantage of photo machinable glass is that it can produce precisely vertical walls and the native glass is suitable for many biological applications such as substrates for genetic analysis. Now moving to brief definition,
Definition of Laser Beam Machining
A laser beam machining is a non-conventional machining method in which the operation is performed by the laser light. The laser light has maximum temperature strikes on the workpiece; due to high temp the workpiece gets melts. The process used thermal energy to remove material from a metallic surface.
Types of lasers
There are many different types of lasers including gas, solid states lasers, and excimer.
Some of the most commonly used gases consist of; He-Ne, Ar, and Carbon dioxide laser.
Solid-state lasers are designed by doping a rare element into various host materials. Unlike in gas lasers, solid state lasers are pumped optically by flash lamps or arc lamps. Ruby is one of the frequently used host materials in this type of laser. A ruby laser is a type of the solid-state laser whose laser medium is a synthetic ruby crystal. The synthetic ruby rod is optically pumped using a xenon flashtube before it is used as an active laser medium.
YAG is an abbreviation for yttrium aluminum garnet which are crystals that are used for solid-state lasers while Nd: YAG refers to neodymium-doped yttrium aluminum garnet crystals that are used in the solid-state lasers as the laser mediate.
YAG lasers emit a wavelength of light waves with high energy. Nd: glass is neodymium–doped gain media made of either silicate or phosphate materials that are used in fiber laser.
Working Principle of Laser Beam Machining
In this process, the Laser Beam is called monochromatic light, which 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.
The Laser Crystal (Ruby) is in the form of a cylinder as shown in the above figure or Diagram with flat reflecting ends which are placed in a flash lamp coil of about 1000W.
The Flash is simulated with the high-intensity white light from Xenon. The Crystal gets excited and emits the laser beam which is focused on the workpiece by using the lens.
The beam produced is extremely narrow and can be focused to a pinpoint area with a power density of 1000 kW/cm2. Which produces high heat and the portion of the metal is melted and vaporizes.
Construction or Main Parts of Laser Beam Machining
1) Power Supply
A high voltage is required for Laser. The power is supplied to the system for exiting the electron. When the power is supplied the electron gets in an excited state that means ready to work.
2) Flash Lamps
Flash lamps is used for providing white and coherent light for the very short duration.
In general, we know the work of capacitor, it is used for storing and releasing the charge. Here it is used during the flashing process.
4) Reflecting Mirror
Reflecting Mirror is used here to reflect the light directly to the workpiece. It is of two types Internal and external.
Lense are provided here for vision purpose. It shows the image into bigger size so that it will be easy to perform operation on the given work piece mark.
Work piece is like the object in which the operation is to be carried out. Example if body needed any laser operation then we are the work piece for this machine, same like manufacturing the objects needs to be drill or hole the Laser machine carried out the operation.
Application of Laser Beam Machining
The following application of Laser beam machining is:
- The laser beam machining process is used for making very small holes.
- Mass macro machining production.
- LBM is used in surgery.
- Selective heat treating of materials.
- Complicated welding of non-conductive and refractory materials.
- Micro-drilling operation.
- Photography in medical science.
- Spectroscopic Science.
Advantages of Laser Beam Machining
The following advantages of laser beam machining are:
- Any material can be machined including non-metal.
- The production rate is high.
- There is no direct contact between the tool and the work.
- There is no tool wear.
- No mechanical force on the work.
- The heat-affected zone is very small.
- Heat treated and magnetic materials can be welded, without losing their properties.
- Soft materials like rubber, plastic can be machined.
- Extremely small holes can be machined.
A disadvantages of Laser Beam Machining
The following disadvantages of laser machining are:
- The overall efficiency of Laser machining is very low.
- It is limited to thin sheets.
- The life of the flash lamp is short.
- It is not possible to remove a large number of metals.
- The machined holes are not round and straight.
- Not able to drill too deep holes.
- It’s having a high cost.
- A very low rate of metal-removing.
So, this is all about Laser Machining, I hope you like my article. I also wrote articles on some other processes to check out those too.