1. Detection of the focal point position. Before laser cutting, the position of the beam focus on the workpiece must be adjusted according to the material. Since laser beams-particularly CO2 gas lasers-are generally invisible to the naked eye, a wedge-shaped acrylic block can be used to detect the focal point position; the height of the cutting torch is then adjusted to place the focus at the desired setting.
2. Key points for the piercing operation. In actual cutting operations, some parts require cutting to begin from within the sheet, necessitating an initial piercing step. One method involves using a continuous laser; for thin sheets, standard assist gas pressure can be used, and the beam can penetrate the workpiece in 0.2 to 1 second, after which cutting proceeds. However, when the workpiece is thicker (e.g., 2–4 mm), piercing with standard gas pressure creates a relatively large melt crater on the surface. This not only compromises cutting quality but also risks damaging the lens or nozzle due to spatter from molten material. In such cases, it is advisable to increase the assist gas pressure while slightly increasing the distance between the nozzle orifice and the workpiece. The drawback of this method is increased gas consumption and reduced cutting speed.
3. Preventing melt-back at sharp corners. When cutting parts with sharp corners using a continuous laser, improper parameter settings or operation can easily lead to self-melting at the corner, preventing the formation of a crisp, sharp angle. This degrades the quality of that specific area and can also adversely affect the subsequent cutting process. The solution is to select appropriate cutting parameters; alternatively, using pulsed laser cutting eliminates the issue of melting at sharp corners.