Laser cladding can be achieved as wire (laser hot wire cladding) or powder cladding. The laser beam creates a molten pool on the workpiece surface, while laser-melted laser coating material (wire or powder) is added to the molten pool. The exposure time is very short, resulting in only a short delay due to rapid cooling. The result is a layer that is metallurgically connected to the base material. It is tougher than those coatings formed by thermal spraying and is also less harmful to health than, for example, hard chrome plating. As part of the laser cladding equipment, the diode laser’s top-hat beam profile creates an especially uniform molten pool, providing the workpiece with a fine-grained, hole-free, and crack-free coating. Post-processing is therefore reduced to a minimum. When integrated into ultra-high-speed laser cladding systems developed by Fraunhofer ILT, our diode lasers are also suitable for producing very thin cladding coatings, which hitherto could only be achieved by hard chromium plating.

What is laser cladding technology? Laser cladding via powder injection technology has been widely used in industrial applications such as rapid manufacturing, part repair, surface coating, and innovative alloy development [2,14-18]. The ability to mix two or more powders and control the feed rate of each powder stream makes laser cladding a flexible process for fabricating heterogeneous components or functionally graded materials. Due to the small local fusion and mixing motion in the laser cladding pool Strong, the technique also allows engineering material gradients at the microstructural level. As a result, materials can be tailored for flexible functional properties in specific applications. The inherently rapid heating and cooling rates associated with laser cladding processes can extend solid solubility during metastable or non-equilibrium stages of production, providing the possibility to create new materials with advanced properties. Laser cladding has been used to process various screws, plastics, and rubber injection machine barrels such as Φ150mm × 160mm. A screw, after laser cladding, is smooth and has no deformation. Pigmentation testing revealed no cracks or pores. After installation, the service life of laser cladding screws is 50-60% longer than that of nitrided high-alloy screws under the same conditions. There is no breakage of the cladding during operation. The same technology can be used to repair parts susceptible to corrosion and erosion in other industries.

Laser cladding uses the same concept as the arc welding method, except that a laser is used to melt the surface of the base material and add material, which can be in the form of wire, powder, or strip. Laser cladding is typically performed using CO 2, Nd: YAG, and fiber lasers. Laser cladding typically produces cladding with low dilution, low porosity, and good surface uniformity. Laser cladding is capable of producing a wide range of surface alloys and composite materials with desired properties. The application of laser beam cladding in surface engineering enables good surface cladding (free of pores and cracks) containing uniformly distributed hard particles in a softer and tougher matrix. In this process, material is fed into the substrate surface beneath the laser beam through multiple pathways including powder blowing, wire feeding, pre-placed powder coating, etc. Through appropriate selection and control, the required properties from the laser beam power density, laser beam travel speed, workpiece surface laser beam diameter, and other processing parameters can be achieved. Key advantages over plasma spraying and arc welding include reduced dilution, reduced thermal distortion (as the substrate absorbs very little energy compared to other alternatives), deposition porosity, and its ability to produce a near-net shape of the component.