Before cutting any material, the distance between the laser focus and the cutting material needs to adjust. Different focal positions tend to result in different degrees of cross-section of the cutting material. The bottom slag is different. The cutting workpieces are different and the materials are different. The position of the focus of the laser cutting machine is different. How to choose correctly?
The focus positioned above the cutting material.
For carbon steel oxygen cutting, suitable for positive focus. The bottom of the workpiece is larger than the upper surface, which is beneficial to slag discharge. Is beneficial for oxygen to reach the bottom of the workpiece to participate in sufficient oxidation reaction. Within a certain focus range, the larger the positive focus, the larger the spot size on the surface of the plate, the more preheating and heat replenishment around the kerf, and the smoother and brighter the carbon steel cutting surface.
For the 10,000-watt laser pulse cutting stainless steel thick plate, the positive focus is adopted. The cutting is stable, which is beneficial to slag discharge and is not easy to anti-blue light;
Negative focus cutting
That is, the cutting focus is inside the workpiece. In this mode, since the focus is far from the cutting surface, the cutting width is larger than the cutting point on the surface of the workpiece, and the required cutting airflow is large and the temperature is sufficient.
When cutting stainless steel, it is suitable for cutting with negative focus, the cutting surface is uniform and the section is good.
The perforation of the plate before cutting, because the perforation has a certain height, the perforation adopts a negative focus, which can ensure the minimum spot size of the perforation, the maximum energy density, and the deeper the perforation position, the larger the negative focus.