Why laser cutting with compressed air? How should I select a specialized air compressor?

Laser cutting is the use of high power density laser beam irradiation of the cut material, so that the material is quickly heated to the vaporization temperature, evaporation of the formation of holes, with the movement of the beam on the material, the holes are formed continuously in a narrow width (such as 0.1mm or so) slit, to complete the cutting of the material.

Laser cutting is widely used in sheet metal processing, metal processing, advertising production, kitchenware, automotive, lamps, saw blades, lift elevators, metal crafts, textile machinery, grain machinery, glasses production, aerospace, medical equipment, instruments and other industries. Laser cutting machine is currently the main melting cutting, vapor cutting, oxygen cutting, scribing and controlled fracture cutting several ways.

Comparison of cutting speeds for several cutting methods:

Cutting Method	Laser cutting	Equal Separation Cutting	oxyethylene fast cutting	Hydrocut
Cutting speed	Very fast.	fast	slow	Very slow

Laser cutting auxiliary gas

Laser cutting machine can cope with a variety of materials and complex shapes of the cutting requirements, in addition to providing high energy laser, auxiliary gas in the cutting process is indispensable, its role is to help combustion and heat dissipation; two is to blow off the cutting of molten stains in a timely manner, to prevent dust clogging of the laser nozzle, and third is to protect the focusing lens and to extend its service life.

The main auxiliary gases used for laser cutting are:

Oxygen (O2): the strong oxidizing nature of high-purity oxygen, the cutting surface is easy to blacken, affecting the subsequent processing;

Nitrogen (N2): general processing of precious metals or very high precision of processing, the cost is higher than oxygen cutting;

Compressed air (Compressed Air): processing a wide range of precision, gas stability, air contains about 20% of oxygen, so it can make up for the lack of oxygen and nitrogen to a certain extent.

Cost analysis of auxiliary gas source

Currently on the market 99.99% liquid nitrogen is about 900~1000 yuan / ton, the cost of nitrogen per Nm3 is 1 yuan / Nm3, liquid oxygen is about 3 yuan / kg, so the cutting industry, if it is a conventional carbon steel cutting, the use of compressed air is a more economical and applicable way, for precious metal cutting or high-precision cutting, the use of nitrogen machine on-site nitrogen production, more convenient and applicable.

For example: the use of Bauder PM15TK air compressor to provide 15.5bar compressed air, can provide 1.27m3 per minute, the model of the air compressor’s full load input power is 13.4kW.

Industrial electricity at 0.8 yuan / degree calculation, the cost of air per m3: 13.4×0.8 / (1.27×60) = 0.14 yuan / m3, in accordance with the actual consumption of 0.5m3 gas per minute, the laser cutting machine works 8 hours a day calculation, then the use of air cutting can be saved every day for the cost of: (1-0.14) x 8x60x0.5 = 206 yuan, such as laser If the laser cutting machine works for 300 days a year, the cost of gas can be saved for one year: 206×300=61,920 yuan.

Three parameters for laser cutting selection

Select compressed air as a laser cutting auxiliary gas, in order to ensure that the best gas consumption and laser cutting machine match, laser cutting selection of three parameters: pressure, flow and quality of the gas source.

Pressure: laser cutting machine supporting air compressor can cut how thick the plate, mainly depends on the laser power, and compressed air pressure has little to do. In the case of laser power is large enough, the higher the compressed air pressure, the better the laser cutting quality, the higher the cutting efficiency.

Such as the use of compressed air as an auxiliary gas laser cutting machine, compressed air after drying and purification, divided into three ways, respectively, as an auxiliary cutting gas, cylinder power source, dust removal gas, cutting gas accounted for the proportion of about 80-90% of the total consumption of compressed air.

For not using compressed air and the use of nitrogen or oxygen as an auxiliary gas laser cutting machine, still have to be equipped with a very small flow of air compressor to provide the cylinder power source, but only need to be 6-7bar atmospheric gas source.

Flow: the size of the flow mainly depends on the size of the nozzle, as mentioned earlier, the nozzle accounts for 80-90% of the gas consumption. Laser cutting machine nozzle has a number of specifications, common seven specifications: 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0. The determination of this flow rate can be obtained through the calculation of the nozzle flow rate, or through the nozzle flow rate table query, or directly ask the laser cutting machine manufacturers.