Laser have various applications in manufacturing processes. Out of these laser welding and laser brazing are important because both of these have applications in space, nano-technology.

1. MODERN
MANUFACTURING
PROCESSES
USE OF LASER BEAM MACHINING
FOR WELDING AND BRAZING

2. LASER BEAM MACHINING
• LASER:- Light Amplification by Stimulated
Emission of Radiation
• Interaction of an intense, highly directional,
coherent and monochromatic beam of light
with a workpiece, from which material is
removed by vaporization.

3. TYPES OF LASER BEAM
1. Solid lasers include the Ruby laser
which uses precious stone to produce
beam of red light.
2. Liquid lasers include the Dye lasers,
which uses organic dye molecules in
liquid to produce a wavelength of
radiation that can be tuned.
3. Gas lasers excites the electron in gases
such as Helium, Neon, Cadmium,
Carbon-dioxide, Nitrogen.

4. LASER BEAM MACHINING

5. MECHANISM
• As Laser interacts with the material, the
energy of the photon is absorbed by the
work material leading to rapid
substantial rise in local temperature.
• This in turn results in melting and
vaporisation of the work material and
finally material removal.
• In laser drilling, the laser beam is
focused over the desired spot size.

6. MANUFACTURING APPLICATION
• Material removal – drilling,
cutting
• Brazing
• Welding
• Cladding
• Alloying

7. ADVANTAGES
• No machining force or wear of the tool
takes place.
• Large aspect ratio can be achieved along
with acceptable accuracy or dimension,
form or location
• Micro-holes can be drilled
• Heat affected zone specially in pulse
laser processing is not very significant
due to shorter pulse duration.

8. LIMITATIONS
• High initial capital cost and maintenance
cost.
• Not very efficient process.
• Presence of Heat Affected Zone –
specially in gas assist CO2 laser cutting.
• Thermal process – not suitable for heat
sensitive materials.

9. LASER WELDING
• Laser welding is a non-contact process
that requires access to the weld zone
from one side of the parts being welded.
• The weld is formed as the intense laser
light rapidly heats the material.

10. PRINCIPLE
• The laser beam is focused onto the workpiece by a set of mirrors.
• When the laser beam is moved relative to the workpiece, the energy
of the focused laser beam melts the metal so that a joint is formed.

11. TYPES OF WELDING MODE
• Conduction mode.
• Penetration or Key-hole
mode.

12. KEYHOLE WELDING
• In this method the laser beam energy is
transferred deep into the material
through a cavity filled with ionised metal
vapour.
• High-power laser welding is
characterised by keyhole welding.
• Laser power density is high and partly
vaporises the metal.

13. CONDUCTION MODE
• In this method the heat is transferred from
the surface into the material by thermal
conduction.
• Conduction mode welding is typical of low-
power lasers where power density is
normally not sufficient to create a keyhole.

14. ADVANTAGES
• The whole welding process can be easily
automated using a CAD/CAM setup.
• No electrode is used in the process.
• No form of tool wear occurs.
• Laser welding is highly specific in
targeting.
• High-quality welds are obtained.

15. APPLICATIONS
• The processes and applications
of laser welding are most
prominent in the automotive
industry.
• Where lasers boost productivity
at a low cost when welding
automotive parts – such as roof ,
door or filter assemblies –
together.

16. HYBRID LASER WELDING
• Hybrid laser-arc welding is a
combination of laser welding and arc
welding.
• Hybrid laser-arc processes, especially
hybrid laser-MiG welding, have been
increasingly applied to welding
applications during recent years.

17. HYBRID LASER WELDING
• Laser beams and electric arcs are quite different welding heat sources.
• Both processes work in a gaseous shielding atmosphere at ambient
pressure.
• Hence it is possible to combine these heat sources to a unique welding
technique referred to as hybrid laser-arc welding.

18. LASER BEAM BRAZING
• It is a joining process for sheet metals
where the filler material with low
melting point is melted with laser beam
while the base material with higher
melting point does not melt.
• In laser brazing the working temperature
is above 450 °C while another process
is laser soldering, where the working
temperature is below 450 °C.

19. LASER BEAM BRAZING
• Laser beam melts the wire and the
melt penetrates into the gaps in the
joint and wets the joint surfaces.
• Filler solidifies and forms a smooth
joint.
• The filler wire can be pre-heated to
increase the process speed.

20. FILLER MATERIALS
Commonly used filler materials are:
• Copper-silicon wire
• Silicon bronzes (e.g. CuSi3, Melting point of 910-1025 °C)
• Aluminum bronzes (e.g. CuAl8, Melting point of 1030-1040 °C).

21. LASER BRAZING OF DISSIMILAR METALS
• Laser Brazing Of Dissimilar Metals is also
possible.
• For example in laser brazing of carbon
steel and aluminum the filler material is
welded to the aluminum part and
brazed to the steel part.
• Carbon steel and stainless steel can also
be brazed easily together.

22. APPLICATIONS
• Sheet metal structures where low heat
input, good corrosion resistance and
reduced need for refinishing work are
important.
• Automotive industry uses laser brazing,
visible in body and door structures.

23. ADVANTAGES
• Excellent joint surface quality.
• Excellent joint corrosion resistance.
• High process speed.
• Reduced need for refinishing work.
• The process is easy to control.
• Joining of dissimilar metals.

24. LIMITATIONS
• Typically only for thin materials.
• Relatively high investment cost.

25. Thank You!