Brass Is Highly Reflective: The primary issue when laser cutting brass is that it is highly reflective of infrared laser light (together with other metals such as gold, silver, and copper). This high reflectivity is worse at the longer wavelength of a CO2 laser compared to the wavelength of a fiber laser. The reflection of the laser beam can cause hazards for both the laser optics and the people and equipment around the laser cutter. If the laser light reflects back to the laser source, causing it to heat up past its design temperature, the laser source may be permanently damaged, necessitating an expensive replacement.Brass Absorbs Very Little Laser Energy: The high reflectivity of brass means that very little of the laser energy that falls on the brass surface is absorbed, as most are reflected. Since most energy is not absorbed by the metal, it is very difficult to cut it.Brass Must Be Molten To Lower the Reflectivity: Brass has a very high reflectivity when it is in a solid state. Once the material is molten, its reflectivity drops substantially, allowing a higher absorption of laser energy. The key to successfully laser cutting brass is therefore to pierce the material quickly—once that has been accomplished, the laser will then fall on molten metal and be more readily absorbed. For example, at the wavelength of a fiber laser (approximately of the order 1.06 μm), copper has a reflectivity of 95% in its solid state, but this drops to 84% when molten.Brass Is Hard To Cut in its Solid State: There is some risk to the machine of laser energy reflecting back to the source when starting the cut on solid brass. It is important to try to limit the length of time that the laser is exposed to the solid metal before it begins to melt.The Right Power Setting: Use a high power setting, preferably the maximum that your machine can provide. For example, 1000 W should be used for a 0.04-inch sheet of copper. For a thicker sheet of 0.25 inches, a power of at least 4000 W is required. High power reduces the time for the material to become molten, therefore minimizing the time that it is at its highest reflectivity.Cutting Speed: Cut at a slightly lower speed. Set the cutting speed at approximately 10–15% less than the maximum rate that can be managed on the sheet. It is important to not let the cut extinguish, as that will require the material to be pierced again. Point of Focus: Keep the point of focus as close to the top surface of the material as possible, while still achieving an acceptable quality of cut. The reason is that the laser energy is focused over a small surface area, causing a higher power density and reducing the time needed for the material to melt.High-pressure Cutting Gas: Nitrogen can be used to cut brass, whereas oxygen may be needed for other reflective metals such as copper. When using nitrogen for brass, the gas acts purely to remove the molten metal mechanically. For materials like copper, the oxygen reacts with the surface at the cut in order to form a copper oxide, which reduces the reflectivity of the metal.Does Higher Laser Power Result in Faster Cutting of Brass?Does Slower Speed Make Brass Cutting Easier?Does Employing Nitrogen To Cut Brass Work Well?Disclaimer