How to solve the difficulties of laser cutting machine processing thick plate
XTLASER cutting machine
Laser cutting machine can be a variety of different thicknesses of metal plate for efficient, fine processing, especially in the cutting of thin and medium plate, laser cutting machine shows amazing efficiency and excellent cutting quality, but as the thickness of the plate increases, the quality of the cut also declines. How to solve the technical difficulties that exist in cutting thick metal plates? New day laser cutting machine manufacturers for you to answer the relevant questions.
Problem 1: Steady state combustion process is more difficult to maintain
For the combustion process to continue, the temperature at the top of the cut must reach the ignition point. The energy released by the ferrous-oxygen combustion reaction alone cannot actually ensure that the combustion process continues. On the one hand, it is due to the continuous cooling of the slit by the oxygen stream ejected from the nozzle, which reduces the temperature of the cutting edge; on the other hand, the ferrous oxide layer formed by combustion covers the surface of the workpiece, hindering the diffusion of oxygen, and the combustion process will be interrupted when the concentration of oxygen is reduced to a certain level.
Thick plate cutting, cutting speed is relatively slow, the workpiece surface iron oxygen combustion speed than the cutting head travelling speed. After the combustion continues for a period of time, the concentration of oxygen decreases and the combustion process follows. Only when the cutting head travels to the position, the combustion reaction starts again. The combustion process at the cutting front is cyclical, which leads to temperature fluctuations at the cutting front and poorer kerf quality.
Problem 2: Difficulty in maintaining constant oxygen purity and pressure in the plate thickness direction
When the laser cutting machine performs metal thick plate cutting, the decrease in oxygen purity is also an important factor affecting the quality of the cut. The purity of the oxygen stream has a very large impact on the cutting process. Oxygen purity decreases, the combustion rate decreases, the combustion rate decreases will greatly reduce the combustion process input to the energy of the cutting slit, reducing the cutting speed; at the same time, the cutting surface of the liquid layer of iron content increases, thereby increasing to the viscosity of the slag, resulting in slag discharged difficult, so that in the lower portion of the kerf there will be a serious slag hangings, so that the quality of the kerf becomes unacceptable.
In order to maintain stable cutting, the purity and pressure of the cutting oxygen flow in the direction of the plate thickness should be basically constant. Traditional laser cutting process, often using ordinary conical nozzle, this nozzle in the thin plate cutting to meet the use of requirements. But in cutting thick plates, with the increase in gas supply pressure, the nozzle flow field is easy to form a surge, surge on the cutting process has many hazards, reducing the purity of the oxygen flow, affecting the quality of the kerf.
There are generally three ways to solve this problem:
First, add preheating flame around the cutting oxygen stream;.
Second, in the cutting oxygen flow around the addition of auxiliary oxygen flow.
Third, the reasonable design of the nozzle wall, improve the characteristics of the air flow field.