57
Contemporary Machining Processes
1.10.5 fuTure develoPmenT of laser aPPlicaTions
Various laser and laser-assisted techniques prove useful in the restoration of worn
machine components, especially in motor industrial and aircraft applications
(Tsegelnik, 2015). Laser cleaning is widely applied to the restoration of aircraft turbines, turning surface contaminations to gas or dust fractions. One of the main benefits of this method is the possibility of cleaning without disassembling the aircraft
engine, thus decreasing time consumption. Similarly, damaged paints and varnishes
can be easily and successfully removed from aircraft surfaces. In the advanced
robotic laser coating removal system, a group of mobile walking robots can perform
successfully unmanned cleaning of smaller aircraft outer surfaces (Tsegelnik, 2015).
Prospects of further development of laser material processing technologies can be
obviously derived from the undisputable advantages of lasers over traditional methods (Haranzhevsky and Krivilev, 2011):
• Extremely high spatial localization of energy
• Exceptionally short time of action, setting important limits to dimensions
of a heat-affected zone
• Lack of contact
• Strict dosage of energy
Despite the large variety of existing lasers, radically new laser systems still continue to emerge, such as a quantum cascade laser (Pecharromán-Gallego, 2017). Of
course, numbers of newly developed basic lasers have decreased in recent decades,
but the broad range of applications is well established and widely applied throughout
the world. Moreover, there is still a growing number of possible new applications of
the existing laser technologies. Capabilities of lasers are multiplied by an immense
number of available wavelength combinations, pulse durations, shapes and power
levels, thus expanding areas of potential future applications. This range is even more
extensive if possible combinations of lasers with other material processing methods
are considered that provide an additional large number of hybrid technologies.
1.11 PROCESSING WITH PLASMA
Plasma is a collection of free atoms or molecules which is partially or fully ionized and
which is normally charged neutral, because each particle interacts simultaneously with
many others, exhibiting a “collective behavior” (Stevens, 2000). Partially ionized plasmas have electron and ion densities in the range of 10 15 –10 19 m –3 , neutral species densities
in the range of 10 19 –10 22 m –3 , and pressures ranging from 0.133 to 1330 Pa. The combination of electrical, thermal, and chemical properties of these plasmas makes them
uniquely feasible for material processing, for the following reasons (Stevens, 2000):
• Electrons in processing plasmas are not in thermal equilibrium with neutral ions or chamber walls, reaching high temperatures of up to 3000 K.
The higher electron temperatures in plasmas produce enhanced chemical
Contemporary Machining Processes
1.10.5 fuTure develoPmenT of laser aPPlicaTions
Various laser and laser-assisted techniques prove useful in the restoration of worn
machine components, especially in motor industrial and aircraft applications
(Tsegelnik, 2015). Laser cleaning is widely applied to the restoration of aircraft turbines, turning surface contaminations to gas or dust fractions. One of the main benefits of this method is the possibility of cleaning without disassembling the aircraft
engine, thus decreasing time consumption. Similarly, damaged paints and varnishes
can be easily and successfully removed from aircraft surfaces. In the advanced
robotic laser coating removal system, a group of mobile walking robots can perform
successfully unmanned cleaning of smaller aircraft outer surfaces (Tsegelnik, 2015).
Prospects of further development of laser material processing technologies can be
obviously derived from the undisputable advantages of lasers over traditional methods (Haranzhevsky and Krivilev, 2011):
• Extremely high spatial localization of energy
• Exceptionally short time of action, setting important limits to dimensions
of a heat-affected zone
• Lack of contact
• Strict dosage of energy
Despite the large variety of existing lasers, radically new laser systems still continue to emerge, such as a quantum cascade laser (Pecharromán-Gallego, 2017). Of
course, numbers of newly developed basic lasers have decreased in recent decades,
but the broad range of applications is well established and widely applied throughout
the world. Moreover, there is still a growing number of possible new applications of
the existing laser technologies. Capabilities of lasers are multiplied by an immense
number of available wavelength combinations, pulse durations, shapes and power
levels, thus expanding areas of potential future applications. This range is even more
extensive if possible combinations of lasers with other material processing methods
are considered that provide an additional large number of hybrid technologies.
1.11 PROCESSING WITH PLASMA
Plasma is a collection of free atoms or molecules which is partially or fully ionized and
which is normally charged neutral, because each particle interacts simultaneously with
many others, exhibiting a “collective behavior” (Stevens, 2000). Partially ionized plasmas have electron and ion densities in the range of 10 15 –10 19 m –3 , neutral species densities
in the range of 10 19 –10 22 m –3 , and pressures ranging from 0.133 to 1330 Pa. The combination of electrical, thermal, and chemical properties of these plasmas makes them
uniquely feasible for material processing, for the following reasons (Stevens, 2000):
• Electrons in processing plasmas are not in thermal equilibrium with neutral ions or chamber walls, reaching high temperatures of up to 3000 K.
The higher electron temperatures in plasmas produce enhanced chemical