The power density at the focal point of the laser can reach 107W/cm² to 1011W/cm² and the temperature can be as high as 10,000 degrees Celsius. It is an ideal heat source for cutting and can make any hard material such as ceramics, carbide, diamond, etc. to be partially melted and evaporated in an instant, and be erupted by the strong shock wave generated. Therefore, we can utilize lasers for cutting and other processing of various materials.
What is the key to making ceramics into art?
1.Features of ceramic materials
Ceramics is currently the fastest growing inorganic non-metallic materials, it is by a variety of metals with oxygen, nitrogen or carbon and other synthetic. It has the advantages of hardness, oxidation resistance, wear resistance, high temperature resistance, corrosion resistance, low coefficient of friction, small coefficient of thermal expansion and light density. Therefore, ceramic is a good material for mechanical parts and cutting blades.
2.Difficulties in processing ceramics
However, ceramics at room temperature almost does not show plastic deformation, the processing surface is easy to produce cracks and corners are easy to crack, these cracks left on the surface will lead to the reduction of its physical properties. At the same time, due to its hard and brittle material, the tool wear during processing is serious, and the material removal rate is low, thus affecting the processing efficiency. Therefore, it is very difficult to machine ceramic materials into parts with precise geometry, high dimensional and form accuracy and low surface roughness by general methods.
3.Laser equipment makes ceramic processing efficient
High absorption of lasers
Even the longer wavelength of the laser, ceramics to its absorption rate is much higher than the general metal. Such as alumina ceramic absorption rate of about 85%, zirconium oxide is up to about 90%, silicon nitride and silicon carbide ceramic absorption rate is also more than 40%, if the ceramic surface is rougher, the absorption rate is further increased, are more than 90%.
Decomposition and sublimation by high heat irradiation
Ceramics such as silicon nitride and silicon carbide have decomposition and sublimation properties when heated at high temperatures. As a result, once it is irradiated by a laser beam with high energy density, localized decomposition and sublimation will occur, which helps to improve the efficiency of laser processing.