The idea of cladding is nothing new; however, laser cladding technologies have seen a significant boost in reliability and efficiency as of late.
Cladding, if you didn’t know, is the process for improving the finish or surface of an object, part, or item that has generally been worn, through extended use. The best way to think of it is as a more aesthetic and functional form of refurbishment or revision. A new surface layer is created on top of the base material, giving it a new or fresh finished look.
This is different from a process known as surface hardening, which involves revamping the surface layer through a substrate, albeit in a thinner form factor.
Cladding essentially relies on the use of new forms of material to the surface to refinish an item. Because of this, there are varying types of materials that can be laid during the process, each with their own properties and characteristics. For example, one material might offer better quality and durability as opposed to reasonable costs and cladding speed.
Traditional Cladding vs. Laser Cladding
For traditional cladding processes, methods such as thermal spraying and arc welding are commonly used. They are considered more traditional and acceptable forms of welding, though please bear in mind that doesn’t necessarily mean they are better or more reliable.
Gas tungsten arc welding or GTAW and submerged arc welding SAW are some great examples of this. During the process, an arc is produced to melt the surface or base material making it more malleable. The clad or surface material is then added—usually in wire or powder form—and melted by the arc, thus creating the new, smooth and revised surface.
Thermal spraying works remarkably similarly to this process, with heat applied to spread and mesh the new surface layer to the item.
Laser-based cladding processes are often much improved over the more traditional forms of cladding. The clad materials are usually applied in the same way however, they are meshed to the item or surface using a high power direct diode laser. The laser emitter generally has a much more precise and capable beam, well suited to metalworking and rapid processing techniques.
Electron beam welding is another form of the process that relies on the reduction of ambient pressure, allowing electrons—hence the electron in the name—to be more tightly controlled. It’s outside the scope of this guide, yet worth mentioning to anyone considering laser cladding resurface methods.
Laser Cladding Advantages
Compared to arc welding and thermal spray methods, laser cladding processes deliver lower heat distortion, reduced dilation, low porosity levels, and better surface uniformity for the new surface layer, obviously. Collectively, this creates a more durable, and more market-ready surface than the previous cladding methods. As a result, there’s little to no need for post-processing after the new surface is created reducing both costs and time associated with cladding techniques.
Furthermore, the precision and high quench rate of diode lasers mean that the surface material is spread using a much finer and reliable grain structure. This translates to better corrosion resistance for the new surface, making the revised component more reliable.
Regarding metalwork, metal-based clad materials can be produced using a diode laser with minimal cracking and delamination; two drawbacks of metallurgical and mechanically bonded coatings.
All of this, combined with the speed and precision of laser cladding makes it a truly competitive solution in comparison to traditional arc welding and thermal spray methods. Laser cladding can be used for just about any form of application that traditional cladding can be used for, including the use of metal and mechanical-based materials.
In metalwork especially, laser cladding can be used to improve and deliver more capable surfaces that are corrosion, wear and impact resistant. That alone makes the process worth its weight in gold, simply because the new surface of the item you’re refinishing must be durable and reliable, especially in regard to metal items. The result is a strictly-bonded, virtually pure coating that is as reliable—if not more so— than the base surface.
Article by —
Megan Ray Nichols
Freelance Science Writer
nicholsrmegan@gmail.com
www.schooledbyscience.com/about
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