A SEMINAR ON

LASER PROCESSING OF MATERIALS &

ITS INDUSTRIAL

APPLICATIONS

CONTENT OUTLINE

Introduction

Applications

Lasers materials processing in Mechanical Industry

Laser Micro machining (MEMS)

Laser processing on electronic materials

Laser processing of Chemical materials

Laser processing materials for Nuclear energy

Laser processing for photovoltaic application

Laser materials processing in Nanotechnology

Laser processing for medical industry

Introduction

Laser materials processing is done on various materials such as metals,

non metals, ceramics, polymer materials.

CO2 and Nd:YAG lasers are known as industrial lasers which are widely

used in industries.

Laser processing is used in various industry such as mechanical industry,

electronic industry also used in chemical processes, nuclear

technology, nano technology, micro machining.

So, we can say that laser can perform all technological task.

Type of Industrial Lasers

Solid state lasers

Nd:YAG (1064 nm)

Ruby (694 nm)

Nd:glass(1062 nm)

Gas lasers

HeNe (632.8 nm)

CO2 (10,600 nm)

Argon (488, 514.5 nm)

Semiconductor laser

InGaAs (980 nm)

Liquid dye lasers

Rhodamine 6G (570 – 640 nm)

Coumarine 102 (640, 515 nm)

Stilbene (403-428 nm)

Type of lasers

Lasers widely used in material processing are CO2 laser and

Nd:YAG laser.

• CO2 Lasers :

CO2 lasers operate at 10.6 nm and metals have high reflectivity at this wavelength.

Instead of CW CO2 laser, a pulsed mode CO2 laser produces high peak powers and

makes possible to work on metals.

• Nd:YAG lasers :

Nd:YAG lasers operate at 1.06 nm where metals are less reflective and are better

candidates for working on metals.

Nd:YAG lasers offer the advantage of compactness.

CO2 lasers are cheaper compared to Nd:YAG lasers.

CO2 lasers are more generally preferred.

Lasers materials processing in

Mechanical Industry

Laser processing of materials

Laser Finishing

Laser Marking

Laser Milling

Laser Striping

Laser Cutting

Laser Drilling

Laser Welding

Laser Etching

Laser Engraving

Laser Machining

Laser Sweeping

Laser Striping

Laser Carving

Laser Cooling

Laser Heating

Laser Sealing

Laser cutting

Laser drillingLaser welding

Laser Engraving

Laser marking

Laser etching

Mechanical Processing on both Metals and Non metals.

Processes require transfer of energy from the laser beam to the work piece.

Happens only if the material has high absorption at the wavelength

corresponding to the laser beam.

Once the surface of the materials absorbs energy, the material starts to melt

and then vaporise.

At high intensity of radiation, the vapour will be ionized to produce

plasma.

Plasma layer formed between the laser and the work piece prevents the

laser beam from reaching the work piece.

Essential that plasma should be removed to increase energy coupling.

Laser should deliver large amount of power.

Intensity of laser beam can be enhanced with a suitable optical system that can

focus the beam into a spot of about 10 to 100 m diameter.

Energy Absorption during Mechanical Processing

Laser Micro machining

(MEMS)

Micro Machining is to ablate or machine small amount of material from the surface of sample.

Nd:YAG pulse laser is used for micromachining.

Intense pulses of UV light from UV lasers are used for such purposes.

The technique is used for

machining of fine, micron-sized

features in polymer materials, for

micro-hole drilling, selective thin-

film removal, surface engineering

and milling for 3-D micro-

structuring.

Laser micromachining

Laser processing materials for

Nuclear energy

In Nuclear power plants, natural uranium is used to fuel the fission reactor.

Natural uranium ore mainly contain two principal isotopes U-238 and U-235.

U-238 is the more abundant isotope but it cannot sustain the fission chain reaction

needed to drive the nuclear reactor.

It is U-235 isotope that sustains a fission reaction.

Differences in the nuclear mass shift the electronic energy levels slightly and

therefore each isotope absorbs light at different characteristic wavelength.

Absorption bands are fairly narrow and lie close to each other.

If the mixture of isotopes is irradiated by a source of narrow bandwidth, it is

possible to excite one isotope without disturbing the other.

Lasers have very narrow bandwidth and can be helpful in this process.

Desired energy can be obtained by tuning a Dye laser to a precise wavelength

with a very narrow bandwidth.

Selectively excited U-235 atoms can

be ionized by applying another short

wavelength light to the mixture.

Ionized U-235 atoms can be

separated from the neutral U-238

atoms using electrostatic fields.

Schematic of Uranium isotope

separation facility

Laser isotope separation

Atomic vapour laser isotope

separation (AVLIS) process

for Uranium enrichment,

(Livermore, USA).

Green light is converted to

red–orange light of three

different wavelengths that

are absorbed only by

Uranium-235.

Laser materials processing in

Nanotechnology

Nanoparticles, Nanomaterials and Nanostructures are building blocks of nanotechnology.

Advanced laser based techniques developed to fabricate nanostructures on polymer surface;

succeeded in producing periodic feature < 200 nm in width.

Cellular response is modified in the presence

of the nanostructures.

Ability to fabricate these structures could also

have an important impact on a wide range of

electronic and photonic devices.

Periodic nanostructures

on polymer surface

Laser induced “Nanojets”

Nanojets:- self-organised structures of the order of 200 nm in diameter that are generated

through the interaction of ultrafast (femtosecond) laser pulses with thin metallic

materials coatings.

Structures are important in the

creation of raised nanoscale

features for biotech applications.

Also, important in the formation of

novel low dimensional structures in

ICT and in the fabrication and rapid

prototyping of plasmonic devices.

Computer simulation of laser-

generated nano jet in 20 nm Ni film

on silica. The coloured areas

represent regions of different

crystalline phase.

Laser processing on

electronic materials

Laser materials processing

Laser Soldering

Laser Drilling

Laser Scribing

Laser CB Cutting

Laser PCB Cutting

Laser Bar coding

Laser Marking Data matrix

Laser Marking IC chips

Photolithography

Bar coding by LASER

Laser marking data matrix

CD cutting by LASER Laser marking IC chips

PCB marking by LASER PCB cutting by CO2 Laser

Types of lasers

CO2 Lasers for metallic material processing :-

Scribing

ND:YAG for non-metallic materials:-

Soldering, Trimming

Pulsed excimer lasers for finer features:-

Photolithography

Laser processing of

Chemical materials

Chemical processing using lasers

Laser spectroscopic chemistry

Laser chemical processing

Laser chemical reaction

Laser spectroscopic chemistry

Laser desorption/ ionization mass spectrometry

Molecular identification by laser spectroscopy

Laser scanning confocal microscopy imaging

Laser chemical processing

Catalytic action

Chemical coating

Isotope separation

Chemical vapour deposition

Intermediate refining

Chemical reactions using laser

Laser flash photolysis

Laser chemical amplification

Laser flash chemical reaction

Laser induced chemical reaction

Laser study of chemical reaction

Laser control of chemical reaction

Laser driven chemical reaction

Laser excited chemical reaction

Laser simulation of super continuum generation

Laser wave electronic steering (chemical bond)

Laser processing for

photovoltaic application

Among laser processes for TF photovoltaics, only laser scribing systems hardly suffer

any competition from other techniques.

Laser scribing systems have the ability to machine narrow patterns on a wide range of

materials in a selective, precise, and cost-effective manner.

It is a noncontact process, meaning that the mechanical stress applied on the micro

machined layers is limited.

Unlike the tip of a mechanical scriber that suffers mechanical wear , a laser scriber when

powered by a diode-pumped solid state laser (DPSSL) can operate continuously for over

10000 hours.

Various applications are securing a bright future for lasers in TF

photovoltaics such as,

• Laser scribing along with other laser processes for TF

photovoltaics

• Lasers are also integrated into various diagnostic tools to

analyze deposition processes of Si thin films

• In the development stage of PV cells, lasers are applied in

several TF characterization methods

Laser processing for

medical industry

Type of Laser processing

Laser cutting

Laser welding

Laser Drilling

Laser Marking

For medical devices, the pin point precision of lasers is the most valuable technology

for cutting, welding, drilling, marking components.

Laser machining is a valuable tool for medical device component manufacturing, and the

development in laser technology have added very compelling benefits to process

capability.

Laser processing is a high performance solution for creating intricate and geometrically

complex features in advanced materials within extreme high tolerances.

No other manufacturing tool provides the same stable, accurate energy needed for

fabricating precision devices, where quality has a profound effect on patient outcome.

Type of lasers used in medical applications

Ruby(694 nm)

Alexandrite(755 nm)

Pulsed diode array(810 nm)

Nd:YAG(1064 nm)

Ho:YAG(2090 nm)

Er:YAG(2940 nm)

Laser eye surgery or laser corneal surgery is a medical procedure that uses a laser to

reshape the surface of the eye. This is done to correct myopia (short-sightedness),

hypermetropia (long sightedness) and astigmatism (uneven curvature of the eye's

surface).

Hard tissue surgical lasers are dominated by Er:YAG lasers operating at the

wavelengths of 2.94 µm.

Laser eye surgery utilizes excimer lasers in the UV range of wavelengths.

CO2 lasers remain the dominant soft-tissue surgical lasers because of their wavelength

and precision.

CO2 laser surgery is praised for minimized bleeding, less swelling and discomfort,

reduced infection risk, and less procedure time, as compared to traditional scalpel

surgery. Applications include oral surgery, periodontal surgery, oncological surgery,

among many others.

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