What are the factors that affect the engraving quality of laser machine cutting
The parameters of laser machine cutting are very important, they directly affect the quality and effect of cutting. So, how to define these professional performance parameters when using a laser cutting machine?
1. The influence of auxiliary air pressure
In laser machine cutting, the auxiliary air pressure can blow away the slag and cool the heated area. For some metal and non-metal materials, inert gas or compressed air is usually used to prevent the material from burning. Such as cutting aluminum alloy materials. Most metal materials use reactive gases (such as oxygen) because oxygen oxidizes the metal surface and improves cutting efficiency. When the auxiliary air pressure is too high, eddy currents will appear on the surface of the material, which weakens the ability of the material to remove the melt, resulting in larger gaps and rough cutting surfaces. When the air pressure is too low, the melt cannot be discharged completely and the bottom surface adheres to the slag. Therefore, the auxiliary gas pressure must be adjusted to obtain the best cutting quality.
2. The influence of laser power
The size of the laser power has a great influence on the cutting speed, cutting width, cutting thickness and cutting quality. The required power depends on the characteristics of the material and the cutting mechanism. For example, materials with good thermal conductivity, high melting point and high reflectivity require higher laser power. Generally, under other conditions, laser cutting has the best laser power for cutting quality. Decreasing or further increasing the power will cause the slag to float or overheat, which will result in a decline in processing quality.
Moreover, as the discharge voltage increases, the laser intensity increases as the peak input power increases, the spot diameter increases and the slit width increases accordingly. As the pulse width increases, the average laser power increases, and the slit width also increases; generally, as the pulse frequency increases, the slit width also becomes wider. When the frequency exceeds a certain value, the width of the space decreases.
3. The influence of cutting speed
In the laser machine cutting process, the cutting speed has a great influence on the quality of the cut material. The ideal cutting speed will make the cutting surface have relatively stable lines, and there will be no slag at the bottom of the material. When the auxiliary air pressure and laser power are fixed, there is a non-linear inverse relationship between the cutting speed and the gap width. When the cutting speed is relatively slow, the action time of the laser energy in the slit will be extended, which will lead to an increase in the width of the slit. When the speed is too slow, the action time of the laser beam is too long, the upper and lower gaps of the workpiece are greatly different, the cutting quality is reduced, and the production efficiency is greatly reduced. As the cutting speed increases, the action time of the laser energy on the workpiece is shortened, the thermal diffusion effect and heat conduction effect are reduced, and the gap width is reduced. result. When the cutting speed is too high, the workpiece material will not be affected due to insufficient cutting heat input. This phenomenon belongs to incomplete cutting, and the molten material cannot be discharged in time. These molten materials will stick out of the slit.
4. Influence of focus position
The focus position is the distance the laser focuses on the surface of the workpiece, which directly affects the surface roughness of the workpiece, the slope and width of the gap, and the adhesion of the slag. If the firing position is too high, the heat absorbed by the lower end of the cutting piece will increase. When the cutting speed and auxiliary air pressure are fixed, the cutting material and the material near the cutting weld will flow to the bottom surface in liquid form. After cooling, the molten material will stick to the bottom surface of the workpiece like a ball; if the position is delayed, the heat absorbed by the bottom surface of the cut material will be reduced, so that the material in the cutting seam cannot be completely melted, and some short and sharp residues Will attach to the bottom surface of the board. Generally, the focal position should be on or slightly below the surface of the workpiece, but different materials have different requirements. When cutting carbon steel, when the focus is on the surface of the steel plate, the cutting quality will be better; when cutting stainless steel, when the focus is about half the thickness of the steel plate, the effect is better.