In the process of laser cutting, there are requirements for the roughness of laser cutting, especially for the workpieces of medium and thick plates. If you do not pay attention during the cutting process, it is likely to cause cutting errors. In general, the roughness of the cutting surface of the laser cutting machine must be controlled.

So how to control it? For laser cutting of plates with a thickness of more than 2mm, the distribution of the roughness of the cutting surface is uneven and varies greatly along the thickness direction. Its change has two significant characteristics:

1) The morphology of the cutting surface is divided into two distinct parts, the upper surface is flat and smooth, the cutting stripes are neat and dense, and the roughness value is small; The lower cutting stripes are disordered, the surface is uneven, and the roughness value is large. The upper part is characterized by the direct action of laser beam, and the lower part is characterized by the erosion of molten metal.

2) The surface roughness in the upper area of the cutting surface is generally uniform and does not change with height; The surface roughness of the lower region changes with the height. The closer the lower edge is, the greater the surface roughness value is, and the greater the surface roughness at the lower edge is. Whether it is continuous laser cutting machine or pulse laser cutting, the cutting surface shows obvious upper and lower parts. The difference is that the cutting stripes on the upper part of the pulse laser cutting surface have a corresponding relationship with the pulse frequency: the higher the frequency is, the finer the stripes are, and the higher the surface roughness is. The cutting stripe density and surface roughness on the upper part of the cutting surface during continuous laser cutting are mainly related to the cutting speed.

Therefore, the surface roughness of the lower edge shall be taken as the benchmark when evaluating the quality of the cutting surface. But the real lower edge is only a line, and the roughness is difficult to measure. It can be replaced by the roughness near the lower edge, which is called “the roughness near the lower edge”.

How to ensure the quality of products, reduce labor intensity, labor costs, and improve the labor environment are the needs of modern production. For example, the boiler products of a company are mainly made of sheet parts, which are different in material and shape. For example, in actual production, the wear plate on the waste heat furnace adopts the form of densely distributed small holes on the stainless steel sheet, and its small holes can only be formed by the use of a metalworking drill. The wear plate of a boiler consumes a box and a half of drill bits, which takes two and a half months to complete. However, the manufacturing cost of the new laser cutting is low because it does not require the consumption of tools and molds. Therefore, it has great advantages not only in the production of small batches of parts with special shapes, but also in batch blanking.

Compared with other thermal cutting methods, laser cutting machines are generally characterized by fast cutting speed and good quality, which can be summarized as follows:

1) Fast cutting speed

Use a 1000W laser cutting machine to cut 2mm thick low carbon steel plate, the cutting speed can reach 6 m/min, and the material does not need to be clamped during laser cutting, which can not only save the fixture, but also save the time of loading and unloading.

2) Good cutting quality

Because the laser spot is small, the energy density is high, and the cutting speed is fast, the laser cutting can obtain better cutting quality. The dimensional accuracy of cutting parts and components can reach ± 0.05mm, and the cutting surface is smooth and beautiful, and the surface roughness is only tens of microns. Even laser cutting can be used as a process without mechanical processing. The parts and components can be directly used. After laser cutting, the width of the heat affected zone is very small, and the performance of the material near the cutting seam is almost unaffected. Besides, the workpiece deformation is small, the cutting accuracy is high, and the geometric shape of the cutting seam is good, The cross section of the slit presents a regular rectangle.

3) High cutting efficiency

The laser cutting machine can generally be equipped with multiple CNC worktables, and the whole cutting process can be fully realized by computer numerical control. The operation is that the NC program can be changed to cut parts of different shapes.

4) Environmental protection

To process parts of different shapes, it is not necessary to change the “tool”, but only to change the output parameters of the laser. The laser cutting process has low noise and low vibration.

5) Compared with the traditional cutting method, laser cutting machine can save materials, improve production efficiency and reduce costs through reasonable nesting and cutting heat effect.