What is laser cladding?
Cladding refers to a process of bonding two dissimilar metals together. Laser cladding is one such cladding process that is used for depositing material on surfaces with the help of lasers. The process commences by using lasers to melt a powdered or wired feedstock material to coat portions of a substrate or to fabricate additive manufacturing technology.
- What is the process of laser cladding?
- What are the uses of laser cladding?
- What are the advantages of laser cladding?
- What type of lasers are used in laser cladding?
- What is automated laser cladding?
What is the process of laser cladding?
Generally, the powder used for laser cladding is metallic in nature. This powder is injected into the cladding system by using either lateral or coaxial nozzles. The metallic powder steam interacts with the laser beam that results in the powder melting and forming a melt pool. This melted powder is then deposited on the substrate. The substrate is then moved in order to solidify the metal pool and generate a track of solid metal. The CAD (Computer-aided Design)system is used for controlling the movement of the substrate that implants solid materials into a set of tracks. The required result is finally obtained after the trajectory ends. This the most commonly used cladding technique with lasers.
In certain systems, the nozzle or laser system is allowed to move while the substrate remains stationary when solidified tracks are produced.
What are the uses of laser cladding?
Laser surface cladding is used for a variety of industrial purposes like:
- It is used for improving the mechanical properties of materials made of metal, ceramic, or polymer.
- It is used for increasing the resistance to corrosion.
- It is used for repairing worn out parts.
- It is used for fabricating metal matrix composites.
- It is used for producing self-lubricating surfaces.
What are the benefits of laser cladding?
The advantages of laser cladding are:
- Laser cladding is good for cladding any shape and structure.
- It has an extremely high cooling rate that is beneficial for creating fine microstructures.
- The final result produced is devoid of crack and porosity.
- It allows cladding in a variety of materials (metal, ceramic, and even polymer).
- This method is good for graded material application.
- It provides low dilution between the substrate and tracks and also ensures a strong metallurgical bond.
- It provides low substrate deformation and has a small heat-affected zone.
- This is a well-developed method for near-net-shape manufacturing.
- For repair parts, this technique provides particular dispositions.
- It involves the use of compact technology.
What kind of lasers are used in laser cladding?
Laser cladding is generally performed with Carbon dioxide or CO2 lasers or Nd:YAG lasers. However, nowadays fiber lasers are also used for laser surface cladding.
Carbon dioxide or CO2 lasers:
Carbon dioxide lasers are used for producing high-power continuous laser beams of infrared light. The principal wavelength bands of these lasers range from 9.6 to 10.6 micrometers. These lasers are known for their high power-efficiency with output power to pump power ratio reaching as high as 20%. The high-power continual laser beams provided by carbon dioxide or CO2 lasers are important for several industrial applications like cladding, wielding and cutting materials such as metal or glass. Certain medium and low power Carbon dioxide lasers are also used for metal engraving.
Nd: YAG (neodymium-doped yttrium aluminum garnet) lasers are a variant of solid-state lasers in which Nd: YAG crystals are used as a lasing medium. The lasing action in the Nd: YAG (neodymium-doped yttrium aluminum garnet) laser is provided by the neodymium Nd(III) ion and the lasing process is similar to that of red chromium ions used in ruby lasers. Nd:YAG lasers play a crucial role in several manufacturing purposes like etching, metal engraving, laser cladding, metal surface polishing, welding, and cutting steel, alloys, or semiconductors.
Optical fiber lasers:
Optical fiber lasers work on the principle of total internal reflection with optical fibers for light transmission. These lasers are primarily used for transmitting light over a long distance without much power loss. This also checks the thermal distortion of the laser beam. Optical Fiber-based lasers are known to produce a higher output power than other laser types. The high surface area to volume ratio of these lasers generates a continuous output power belonging to the kilowatt level with efficient cooling. The distortion in the optical path due to various thermal issues is reduced by the waveguide of an optical fiber.
What is automated laser cladding?
In normal laser cladding machines, parameters like laser focal point, laser power, powder injection rate, substrate velocity, etc. need to be provided manually by the technician. The process also demands constant supervision. Therefore, to ease the process of cladding, automated technology has been incorporated. These automated machines have sensors to guide and monitor the entire process of cladding. These sensors monitor the substrate’s metallurgical properties (like the rate of solidification), temperature information, and geometry (such as width and height of deposited track).
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