2. History of Laser Beam Welding
1917 Postulate of stimulated emission by Einstein
1950 Physical basics and realisation of a maser (Microwave Amplification
by Stimulated Emission of Radiation) by Townes, Prokhorov, Basov
1954 Construction of the first maser
1960 Construction of the first ruby laser (Light Amplification by
Stimulated Emission of Radiation)
1961 Manufacturing of the first HeNe lasers and Nd: glass lasers
1962 development of the first semiconductor lasers
1964 Nobel price for Towens, Prokhorov and Basov for their works in
the field of masers construction of the first Nd:YAG solid state lasers
and CO gas lasers
1966 Established laser emission on organic dyes since increased
application of CO and solid state laser
1970 Technologies in industry
1975 First applications of laser beam cutting in sheet fabrication industry
1983 Introduction into the market of 1-kW-CO lasers
1984 First applications of laser beam welding in industrial serial production
3. Laser Beam Welding (EBW)
Electron Beam Welding (EBW) is a welding process
which produces coalescence of metals with the heat
obtained from a concentrated beam composed primarily
of high- velocity electrons impinging upon the surface to
be joined.
Heat is generated in the work piece as it is bombarded
by a dense stream of high- velocity electrons. Virtually all
of the kinetic energy of the electrons is transformed into
heat upon impact.
5. Characteristics of Laser Beams Welding
A high energy concentration in the focal point of the
electron beam.
Welding in vacuum leads to a special purity of the welded
seam and to the minimization of weld defects.
Automated welding in vacuum with electrically well
controllable welding parameters guarantees a high
reproducibility of the weld quality.
The high power density of the electron beam allows
working with very high welding speeds.
The high welding speeds and the favorable total efficiency
allow high productivity with relatively low energy
10. Weldding Defect
Undercuts/Overlaps
Grain Growth
A wide ∆T will exist between base metal and HAZ. Preheating and
cooling methods will affect the brittleness of the metal in this region
Blowholes
Are cavities caused by gas entrapment during the solidification of the
weld puddle. Prevented by proper weld technique (even temperature
and speed)
11. Weldding Defect
Inclusions
Impurities or foreign substances which are forced into the weld puddle during
the welding process. Has the same effect as a crack. Prevented by proper
technique/cleanliness.
Segregation
Condition where some regions of the metal are enriched with an alloy
ingredient and others aren’t. Can be prevented by proper heat treatment and
cooling.
Porosity
The formation of tiny pinholes generated by atmospheric contamination.
Prevented by keeping a protective shield over the molten weld puddle.
14. Conclusion
Laser beam welding opens up many opportunities for
designing and economically joining machine parts. Various
branches of industry, which use laser beam welding
include electronics, automotive, and food processing.
