In the field of production, it is often necessary to cut different materials. The most common are metal  and nonmetal. What is the difference between the two different materials?
 

Laser cutting of metal materials

Almost all metal materials have high reflectivity to infrared ray at room temperature. For example, the CO2 laser absorption rate of 10.6 pum is only 0.5%~10%. However, when a focused beam with a power density of more than 106W/cm2 irradiates the metal surface, the surface will start to melt in a few microseconds. The absorption rate of most molten metals will rise sharply, generally to 60%~80%. Therefore, CO2 lasers have been successfully used in many metal cutting practices.
 

The maximum thickness of carbon steel plate that can be cut by modern laser cutting system has exceeded 20mm. The oxygen-assisted melt cutting method is used to cut carbon steel plate. The cut can be controlled within a satisfactory width range, and the cut of thin steel plate can be narrow to about 0.1mm. Laser cutting is an effective method for processing stainless steel plate. The heat-affected zone can be controlled in a small range, so as to maintain its corrosion resistance. Most alloy structural steel and alloy tool steel can obtain good cutting quality by laser cutting.

Aluminum and aluminum alloy cannot be cut by oxygen fusion, and the fusion cutting mechanism must be used. Aluminum laser cutting needs high power density to overcome its high reflectivity to 10.6 um wavelength laser. The YAG laser beam with a wavelength of 1.06um can greatly improve the cutting quality and speed of aluminum laser cutting due to its high absorption.

Titanium and titanium alloys commonly used in the aviation industry use oxygen as the auxiliary gas, which has violent chemical reaction and fast cutting speed, but it is easy to form oxide layer on the cutting edge, and even cause burnout. It is safer to use inert gas as auxiliary gas to ensure cutting quality.

Most nickel-based alloys can also be cut with oxygen flux. The reflectivity of copper and copper alloys is too high to be cut with 10.6pm CO2 laser.

Laser cutting of non-metallic materials

10.6 um CO2 laser beam is easily absorbed by non-metallic materials. Its low reflectivity and evaporation temperature make almost all the absorbed light energy enter the material, and cause evaporation to form holes in an instant, and enter a virtuous cycle in the cutting process. Plastic, rubber, wood, paper products, leather, natural fabrics and other organic materials can be cut by laser. However, the thickness of wood should be limited. The thickness of wood should be within 75mm, and the thickness of laminate and particleboard should be around 25mm. In inorganic materials, quartz and ceramic can be cut by laser, the latter is suitable for controlling fracture cutting, and high power is not allowed. Glass and stone are generally not suitable for laser cutting.

Other materials that are difficult to be processed by conventional methods, such as composite materials and cemented carbide, can be cut by laser, but reasonable cutting mechanism and process parameters must be selected through experiments.

About HGTECH: HGTECH is the pioneer and leader of laser industrial application in China, and the authoritative provider of global laser processing solutions. We have comprehensively arranged laser intelligent machine, measurement and automation production lines, and smart factory construction to provide overall solutions for intelligent manufacturing.