Laser cladding, also known as laser metal deposition, is a technology that adds one material to the surface of another material. Laser cladding involves feeding a stream of metal powder or wire into a molten pool created by a laser beam as it scans a target surface, depositing a coating of the selected material. Laser cladding technology enables materials to be deposited accurately and selectively with minimal heat input to the underlying substrate. The laser cladding process can improve the performance of part surfaces, including better wear resistance and repair of damaged or worn surfaces. Creating this mechanical bond between the substrate and the layers is one of the most precise welding processes available.
Laser cladding How does it work? Laser cladding can be performed using wire (including hot or cold wire) or powder raw materials. The laser creates a molten pool on the surface of the workpiece while adding wire or powder to it. Although the laser is very powerful as a heat source, the exposure time is short, which means solidification and cooling times are rapid. The result is a metallurgical bond layer that is tougher than thermal spraying and less hazardous to health than the hard chrome plating process. The ability to mix two or more powders and control the feed rates of both separately means this is a flexible process that can be used to create heterogeneous components or functionally graded materials. Additionally, laser cladding allows the engineering of material gradients at the microstructural level due to local fusion and mixing in the molten pool, meaning that cladding materials can be tailored for functional performance in specific applications. There are many variations of laser cladding and laser cladding technology. The description in this article will focus primarily on traditional (and mainstream) laser cladding. However, there are newer and more advanced variations of this technology, including the application of ultra-high-speed lasers in the EHLA process, where the powder is fed into a focused laser beamline above the substrate. This ensures that the deposited material has melted before contact with the substrate, still forming a very shallow molten pool on the substrate, allowing the deposited material to cool and solidify in contact with the underlying material, thereby reducing the amount of heat reaching the substrate. The following components and depth of dilution and thermal effects. This small dilution creates the ability to produce thinner coatings (20-300µm), enabling the desired chemistry within 5-10µm.
Laser cladding offers several advantages over traditional coating processes. The advantages of laser cladding include providing higher quality coating materials (including high bond strength and integrity), virtually no distortion and dilution, and enhanced surface quality. These benefits include the ability to place customized performance-enhancing materials exactly where needed; Can be used with a variety of materials, including custom alloys or metal matrix composite (MMC) designed substrates and layers; Little or no deposits Porosity (>99.9% density); relatively low heat input resulting in a narrow heat affected zone (EHLA as low as 10µm); small deformations in the substrate reducing the need for corrective machining; easy to automate and integrate into CNC and CAD /CAM production environment; reduced production time; improved thermal control through laser power modulation; ability to produce functionally graded parts; precise deposition rate, depending on equipment and application characteristics; good mechanical properties; suitable for repair of worn parts, etc. While there are many advantages to laser cladding, the technology also has some disadvantages, including Expensive setup costs for capital equipment; The large equipment means it is generally not portable, although portable on-site solutions do exist. High build rates can lead to cracking (although for some materials this can be eliminated with additional thermal control measures, such as preheating and post-deposition cooling control).
