In the process of cutting with CNC flame cutting machine, different cutting defects often appear in one way or another. In order to improve the cutting quality, the key points of quality control under different cutting conditions are briefly introduced:

1. Problems needing attention in forging and cutting

Because the oxide scale on the surface of forgings is thick, and the ignition point of the oxide scale is higher than the melting point, cutting is easy to be interrupted, which leads to the decline of cutting quality and working efficiency. Therefore, when cutting forgings, the oxide scales on the upper and lower surfaces in the cutting area should be removed before cutting to improve the cutting speed and quality.

2. The key points to prevent the tooth plate of cold bed from cutting deformation.

How to control the deformation of the workpiece is very important in cutting. If the cutting route is arranged according to the routine, the workpiece will be deformed out of tolerance, even if it is reshaped, it will be difficult to meet the size requirements, and the product will eventually be scrapped. Therefore, it is very important to arrange the gas cutting route reasonably.

3. Some points that should be paid attention to in thick plate cutting.

When cutting a thick steel plate, the temperature decreases downward from the upper surface. At the beginning of cutting, the oxygen pressure gradually increases and finally reaches the same in the thickness direction of the steel plate. This leads to inconsistent combustion in the thickness direction of the steel plate at the cutting start position, and defects occur at the cutting start end of the workpiece.

To avoid defects, the following methods can be adopted:

(1) adopts circular arc feed to increase the length of lead-in line and avoid directly entering the point. This method has good effect and is widely used in production. Its disadvantage is that it wastes materials.

(2) Use ignition match. The method is to add a steel plate close to the thickness of the steel plate at the entrance point, and there can be no gap near it. The cutting knife should be cut into the fire bar, and ignition match will guide the flame of the cutting tool to the bottom of the steel plate, so that the burning speed of the steel plate can be consistent from top to bottom, and the best cutting section can be obtained. Ignition match can be replaced by chips. This method reduces the distance between the workpiece and the edge of the plate, reduces the generation of scrap, and effectively improves the utilization rate of the plate. Ignition match is more practical when cutting extra-thick steel plates.