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Contemporary Machining Processes
• PAW offers a greater welding speed, greater energy concentration, and
higher efficiency than GTAW, which makes it one of the most effective processes for many applications. PAW gives better penetration than GTAW and
welding in the keyhole mode can make full-penetration welds in a relatively
thick material with a single pass.
• PAW uses a nonconsumable tungsten or tungsten alloy electrode. The electrode contamination is minimized, which extends its service life. An electrode can usually last for an entire production shift without needing to be
reground.
• PAW offers a large tolerance to joint gaps and misalignment. Although the
arc is constricted, the plasma column has a significantly larger diameter
than the electron or laser beams. As a result, PAW minimizes the need for
costly joint preparation and reduces or eliminates the need for filler metal.
• PAW provides a high depth-to-width ratio of a plasma weld compared to
a GTAW weld, which can greatly reduce angular distortion and residual
stress. Narrower HAZ, fewer internal defects, and better welding processing properties make it an effective method to weld structural components
with difficult-to-weld rear sides.
It can be stated that PAW has the potential to replace GTAW in many applications
as a primary process for precise joining. However, the PAW equipment, including
power supply and electric control systems, is more complex and costly, and the need
for water cooling of the torch sets limitations on how small the torch can be (Wu
et al., 2016).
Plasma cladding and sputtering belong among additive processing or surface
engineering methods. A plasma cladding machine can be integrated with threedimensional CAD software in order to tailor the required pattern. With a fully automated 6-axis CNC device, parts up to 15 m can be cladded to the highest quality,
forming wear-resistant coatings and films to improve performance of components.
Due to the low heat input, dilution is reduced to a minimum, so that an obtained
alloy maintains optimum wear-resistant properties. The heat-affected zone under the
surface is very thin, so part distortion is practically absent, which allows processing of thin-walled components. The entire process is highly reproducible; therefore,
homogeneous coating deposition can be obtained with a constant and controlled
quality (Chandrasekar et al., 2016).
Sputtering is a subset of plasma-material interactions, a phenomena-rich field
involving interactions that can occur between the plasma species, including ions,
electrons, neutral particles, and radiation on the one hand, and the material surface
on the other. Essentially, plasma sputtering belongs to the physical vapor deposition
(PVD) category, where vaporized atoms or molecules from a liquid or solid phase are
transferred through a vacuum or low-pressure system to be deposited and condensed
onto a substrate surface. The ultimate thickness of the obtained thin film varies
between 1 and 1,000 nm (Rasouli et al., 2021).
Plasma is also used in other methods of surface engineering, being a valuable tool
for obtaining both surface and bulk properties, such as protection against corrosion,
Contemporary Machining Processes
• PAW offers a greater welding speed, greater energy concentration, and
higher efficiency than GTAW, which makes it one of the most effective processes for many applications. PAW gives better penetration than GTAW and
welding in the keyhole mode can make full-penetration welds in a relatively
thick material with a single pass.
• PAW uses a nonconsumable tungsten or tungsten alloy electrode. The electrode contamination is minimized, which extends its service life. An electrode can usually last for an entire production shift without needing to be
reground.
• PAW offers a large tolerance to joint gaps and misalignment. Although the
arc is constricted, the plasma column has a significantly larger diameter
than the electron or laser beams. As a result, PAW minimizes the need for
costly joint preparation and reduces or eliminates the need for filler metal.
• PAW provides a high depth-to-width ratio of a plasma weld compared to
a GTAW weld, which can greatly reduce angular distortion and residual
stress. Narrower HAZ, fewer internal defects, and better welding processing properties make it an effective method to weld structural components
with difficult-to-weld rear sides.
It can be stated that PAW has the potential to replace GTAW in many applications
as a primary process for precise joining. However, the PAW equipment, including
power supply and electric control systems, is more complex and costly, and the need
for water cooling of the torch sets limitations on how small the torch can be (Wu
et al., 2016).
Plasma cladding and sputtering belong among additive processing or surface
engineering methods. A plasma cladding machine can be integrated with threedimensional CAD software in order to tailor the required pattern. With a fully automated 6-axis CNC device, parts up to 15 m can be cladded to the highest quality,
forming wear-resistant coatings and films to improve performance of components.
Due to the low heat input, dilution is reduced to a minimum, so that an obtained
alloy maintains optimum wear-resistant properties. The heat-affected zone under the
surface is very thin, so part distortion is practically absent, which allows processing of thin-walled components. The entire process is highly reproducible; therefore,
homogeneous coating deposition can be obtained with a constant and controlled
quality (Chandrasekar et al., 2016).
Sputtering is a subset of plasma-material interactions, a phenomena-rich field
involving interactions that can occur between the plasma species, including ions,
electrons, neutral particles, and radiation on the one hand, and the material surface
on the other. Essentially, plasma sputtering belongs to the physical vapor deposition
(PVD) category, where vaporized atoms or molecules from a liquid or solid phase are
transferred through a vacuum or low-pressure system to be deposited and condensed
onto a substrate surface. The ultimate thickness of the obtained thin film varies
between 1 and 1,000 nm (Rasouli et al., 2021).
Plasma is also used in other methods of surface engineering, being a valuable tool
for obtaining both surface and bulk properties, such as protection against corrosion,