Metal laser cutting is a stable, reliable, and very accurate fabrication process. By focusing a concentrated beam of high-powered energy through an aperture, laser cutting literally slices through the material by melting, vaporizing, and ablating it to the point of ignition. Through CNC programming, cutting efficiency is achieved more by the speed of the laser beam than the raw power generated from it. When cutting, the residual molten material is blown out of the way by the high-density airflow from the beam. The result is a clean cut, with maximized precision, smooth edges, and exceptionally tight tolerances.
Nonetheless, there are several common issues with metal laser cutting that operators should be aware of or observe in order to avoid them. Though the process is an environmentally friendly one that offers little risk to the operator, like any machine, if it is not operated as directed it can cause damage to the material or even personal injury. Laser cutting is a hands-on process. Obviously, operators should never leave the machine while it is working. For safety, the metal should be free of flammable lubricants or oils, and just as important, no flammable or explosive material should be in the area of the laser cutting machine.
Even though laser cutting produces precision cutting, there are factors that should be addressed to ensure the accuracy of the cut. Problems could arise due to the equipment such as table vibration, auxiliary gas, power output, or as a result of the physical and chemical properties of material itself. Material quality and the amount of elements that comprise the metal can impact the accuracy of the cut, and different elements have different reactions and melting points which can affect the quality of the cut. Because laser cutting is a sensitive process, be sure the equipment such as the table is stabilized and functioning properly, and that the metal has a consistent material composition.
To ensure a precision cut, the focal position of the beam needs to be accurate as does the cutting speed. The focal position of laser cutting machines is of particular importance. The cutting focus position, i.e., the actual spot size of the beam, is proportional to the length of the lens. Though it is possible to manually set the focal position, the majority of machines have automatic focus to ensure accuracy and precision. The feature adjusts automatically relative to the material and its thickness. Automatic focus will significantly improve the efficiency of the laser cut, and do so in a far more reduced time.
Laser cutting applications are more difficult the thicker materials. There is a significant advantage in cutting metal less than 20mm thick. But the effectiveness of the cut decreases as the material becomes thicker, with maximum cutting thickness limited to 25mm. Attempting to cut thick materials increases the chance for experiencing blowout or thermal runaway and damaging the material. For laser cuts between 20mm and 25mm, to improve precision, further focus the beam and reduce the spot size to transform the laser into a sharper cutting tool.
With thickness an issue, it’s also important to note that part geometries are also affected differently. Part geometries that are complicated to cut can present a challenge. Corners and smaller parts can absorb more heat if consistent cutting speeds are not maintained. When cutting speeds are altered, the cut is less accurate. To correct, when cutting intricate part geometries, speed up the laser when cutting curves and corners to avoid overheating.
Overall, metal laser cutting is an exceptionally flexible fabrication process that provides high speed quality cutting for parts and components used in a wide range of applications. Manufacturers rely on laser cutting to fabricate parts in automobile manufacturing, aerospace industry, durable goods for residential and commercial kitchens, manufacturing machinery, fitness equipment, sheet metal processing, and many other industries.