Laser Applications in Surface Modifications

By K.Prem Kumar

13R05A0311

CONTENT

LASER DEFINITION

HOW LASER WORKS

TYPES OF LASER’S

GENERAL APPLICATIONS OF LASER

LASER SURFACE MODIFICATIONS

APPLICATIONS OF LASERS IN SURFACE ENGG AND SURFACE MODIFICATIONS

LASER

Light Amplification by Stimulated Emission of Radiation

DEFINITION OF LASER

DEFINITION: A laser is a device which is built on the principles of quantum mechanics to create a beam of light where all of the photons are in a coherent state - usually with the same frequency and phase.

Emission of a laser beam

WORKING OF LASER

In simplest terms, a laser uses light to stimulate the electrons in a "gain medium" into an excited state (called optical pumping). When the electrons collapse into the lower-energy unexcited state, they emit photons . These photons pass between two mirrors, so there are more and more photons exciting the gain medium, "amplifying" the intensity of the beam. A narrow hole in one of the mirrors allows a small amount of the light to escape (i.e. the laser beam itself).

Ordinary and laser light sources

TYPES OF LASERS

SOLID STATE LASERS

LIQUID(DYE) LASERS

GAS LASERS

SEMI CONDUCTOR LASERS

CHEMICAL LASERS

X-RAY LASERS

General applications of lasers

Laser surface modification process

Laser Surface modification (LSM) covers a wide spectrum of surface modification routes.

This can induce physical changes like changes in surface morphology and roughness, as well as chemical changes like changes in chemical composition.

Laser surface modification (LSM)

The laser has some unique properties for surface heating The electromagnetic radiation of a laser beam is

absorbed within the top atomic layers for opaque materials, such as metals

There are no associated hot gas jets, eddy currents or even radiation spillage outside the optically defined beam area

In fact the applied energy can be placed precisely on the surface only where it is needed

Laser surface Applications

Hardness increase

Strength increase

Reduced friction

Wear reduction

Increase in fatigue life

Surface carbide creation

Creation of unique geometrical wear patterns

Tempering

Applications of lasers in surface engineering

Applications of lasers in surface modifications

Typical laser applications

By K.Prem Kumar(stunner) 13R05A0311