Laser cutting machine auxiliary gases

Laser cutting machine are basically three types of gas can be used for cutting, nitrogen, oxygen, air, according to the machining materials and auxiliary gases are not the same as those used by different requirements, small make up today's discuss different auxiliary cutting out what is the difference between the quality of the gas. Nitrogen and oxygen condition incised seam width is compared under the same cutting parameters, auxiliary gas for oxygen cutting seam width should be greater than the kerf width of nitrogen. Cut this is because aerobic oxidation happens between material and oxygen reaction, oxidation reaction gives off heat accounts for some 70% of the cutting energy and materials to absorb more energy, more melting, cutting seam width is greater. Nitrogen and oxygen in the condition of the surface roughness comparison by surface roughness measuring instrument measured under the condition of nitrogen and oxygen cutting process parameters better slitting surface roughness, such as table 3 - 25, auxiliary gas for N2 when cutting parameters for laser power 1000 w, cutting speed, 4. 5 m/min, nozzle distance from surface 0. 5 mm, 12 kgN/cm2 gas pressure, Auxiliary gas for O2 when cutting parameters for laser power 500 w, cutting speed is 3 m/min, nozzle distance away from the workpiece surface is 0. 5 mm, gas pressure, 7 kgN/cm2. Auxiliary gas using N2 than using O2 smaller kerf surface roughness can be obtained. This is because in the aerobic, cutting the oxidizing reaction between material and oxygen, alloy elements in the material reacts with oxygen compounds, its organizational structure differs from the parent metal to cause uneven in the kerf surface, due to the fast oxidation reaction speed, when the cutting speed lags behind the oxidation reaction easily in the surface cutting kerf width stripe, so aerobic cutting surface roughness is bigger. Surface under the condition of nitrogen and oxygen hang slag is by comparing the cutting and anaerobic and aerobic cutting kerf surface hang slag thickness, hang slag during the aerobic anaerobic cutting than cutting the thickness is smaller. The results with other literature, on the other hand, in the general aerobic cutting, alloy elements in the material can react with oxygen and generate compound, the compound illiquid, larger adhesion, tend to be more easy to hang slag on kerf surface formation. Experiments in this paper the reasons of the abnormal is the auxiliary gas pressure is large enough, oxygen cutting oxygen cutting low carbon steel pressure in other literature is only 2 ~ 4 kgN/cm2, in this paper, experiments of oxygen pressure is about 7 kgN/cm2, the oxygen of slag ability is very strong, in the process of cutting the melt rarely adhesion on the surface material, the surface is small, hang slag and aerobic cutting materials react with oxygen to generate other compounds, the composition of the melt and anaerobic melt cutting the composition is different, these reasons result in this experiment the aerobic hang slag thickness cutting the smaller instead. Under the condition of nitrogen and oxygen cutting stripe is taken by a stered microscope and camera out under the condition of nitrogen and oxygen cutting stripe, macro, FIG. 3 24 for auxiliary gas N2 kerf profile, macro, when the process parameters for laser power 1000 w, cutting speed 2. 5 m/min, nozzle distance from surface 0. 5 mm, 12 kgN/cm2 gas pressure, Figure 3 - 25 for auxiliary gas for O2 kerf profile, macro, process parameters for laser power 500 w, 1 cutting speed. 5 m/min, nozzle distance from surface 0. 5 mm, gas pressure, 7 kgN/cm2. Nitrogen gas cutting, slitting surface can't see clear cut stripes, surface stripe inconsistent, and the surface is uneven and not smooth, trimming and hang slag produced; Figure 3 - by You can see 25, oxygen cutting, can see star cut stripes, thicker, depth is shallow, the fringe spacing slitting surface is flat and level. Stripes on the surface of the kerf width and is closely connected with the surface roughness, former section surface roughness under two kinds of auxiliary gas, we can know that fringe spacing and surface roughness, there is a direct ratio in the absence of oxygen cutting, cutting surface roughness is small, thin stripes, see clear cut stripes; Aerobic cutting, due to the material and oxygen oxidizing reaction, and oxidation reaction speed is far greater than cutting speed, cutting the stripe is clear, fringe spacing is bigger. Described above under the condition of oxygen and nitrogen laser cutting of mild steel slitting quality comparison shows that using nitrogen cutting low carbon steel can obtain better cutting quality, its smaller kerf width is small, the surface roughness, surface have no obvious cutting kerf width stripes; And use oxygen cutting low carbon steel, surface has obvious cutting kerf width stripes, kerf width is bigger, but also can obtain no hang slag cut seam. Although nitrogen gas cutting quality is good, but the price is expensive, the required laser power is larger, the cutting cost is high, can consider when cutting low carbon steel using oxygen instead of nitrogen gas cutting.