Effects of different auxiliary gases on laser cutting parameters

Influence on cutting quality

   Hair produced by the oscillator laser through the lens, after being together in a little tiny spot formation, through the lens of precise control and the plate distance, guarantee the stability of laser speckle on material thickness direction of a certain position, at this time due to the effect of convergence of the lens, the light spot place gathered very large power density laser energy and power density generally can reach 106 ~ 109 w/cm2, instantly melt after materials absorb light energy, through the use of auxiliary gas cutting the molten liquid blowing away from the material to finish machining.

   In the whole cutting process, the main role of auxiliary gas is to form a driving force to remove the molten metal liquid from the material itself. In this process, different kinds of gas have different effects on the material and section:

oxygen

   When oxygen is used as an auxiliary gas, while blowing away the molten metal liquid, oxidation reaction will also occur to promote the endothermic melting of the metal, so as to realize the melting of thicker materials. This process will significantly improve the processing capacity of laser.

nitrogen

   When nitrogen is used as an auxiliary gas, a protective atmosphere will be formed around the molten metal liquid to prevent the material from being oxidized, thus ensuring the quality of the cutting surface.But at the same time, because nitrogen doesn't have the oxidation capacity to enhance heat transfer, it doesn't help with cutting as oxygen does.

air

   Make up approximately 78% of nitrogen in the air, oxygen accounted for about 21%, when using air as auxiliary gas cutting, due to the presence of oxygen oxidizing reaction makes the cutting section is necessarily, but at the same time as a result of the existence of a large number of nitrogen, oxygen oxidation reaction of low enough to enhance heat transfer, cutting ability won't raise, so air cutting effect can be understood as somewhere between nitrogen and oxygen cutting, cutting and benefits is air cutting cost is very low, all cost is caused by the air compressor to provide air power consumption, and the consumption of the air line filter.

Using range

Carbon steel plate

   When using air as auxiliary gas for cutting, the cutting section will produce some burrs after the thickness of the plate exceeds 1.5mm, but the burrs generated are not sharp, and the paper will not be cut during the paper cutting test.For different power and different types of vibrators, the maximum thickness of air as auxiliary gas can be cut is different.

Stainless steel plate

When air is used as auxiliary gas for cutting, yellow oxide layer will be produced in cutting section.

Aluminum plate

When air is used as auxiliary gas for cutting, cutting burr will be reduced relative to nitrogen.

Impact on cutting of different parts

Carbon steel plate

   When using air as auxiliary gas to cut, the part section will produce small burr, but burr is not sharp, can be applied to the burr requirements are not high on the parts.

Stainless steel plate

   As air is an auxiliary gas, the cutting surface of the material will be oxidized after processing, which will lead to slag inclusion and porosity in the weld bead during the welding of the cutting section, which will affect the quality of the weld bead and thus reduce the strength of the welding part.Therefore, the use of air as an auxiliary gas to complete the parts after the completion of welding, it is necessary to weld the oxidation layer of the welding section, so as to improve the welding quality.

Aluminium and aluminium alloy plates

   Cutting burrs can be reduced by using air as an auxiliary gas, but are larger if nitrogen is used.