Application of nitrogen in laser cutting
Laser cutting uses nitrogen to solve many processing problems in actual production, and expands the processing range to the fields where oxygen cutting is difficult to process, such as aluminum and brass. The following describes its applications in various materials and fields.
1. carbon steel
Carbon steel is cut with oxygen. The surface temperature is very high due to carbon assisted melting and oxygen combustion. When cutting holes with sharp corners and diameters smaller than the material thickness, too much heat is concentrated in the narrow area, so that the cutting quality cannot be guaranteed. Nitrogen does not assist in combustion and has a cooling effect, which is suitable for solving such processing problems and can improve product quality.
2. stainless steel
In consideration of cost, the oxidation of cutting edge does not affect the use of stainless steel parts. Oxygen cutting is used. However, the content of alloy elements such as Ni in stainless steel is large, the viscosity of melt is large, and the fluidity is poor. The low air pressure during oxygen cutting is easy to lead to quality defects such as slag sticking. When welding stainless steel, the oxidation layer seriously affects the welding quality, especially argon arc welding. Nitrogen cutting provides high-quality non oxidation section, which meets the high requirements of stainless steel welding for cutting section.
3. aluminum and brass
Aluminum and brass have high reflectivity and low absorptivity to laser, which requires high power to melt materials. In addition, it shall be equipped with a reflection and absorption device so that the uneven linear wave will not be reflected back to the lens to protect the safety of the laser. Nitrogen cutting is required.
The melting point of aluminum is low. Oxygen can be used to cut aluminum with thickness less than 3mm, but the quality is very poor, and the section has hard burrs. The nitrogen cutting section is smooth, and the effect of no burr can be obtained if the thickness is less than 4mm. Due to the high viscosity and thermal conductivity of aluminum, the melt may have cooled before blowing away, so burrs are easy to appear. Reduce the surface roughness value by adjusting the focus, increasing the air pressure and reducing the speed, so as to ensure that the burr can be easily removed.
Etching is a kind of special cutting, and the energy is only 5% of the basic power. It only acts on the surface of the material and is mainly used for etching marks. The oxygen etching temperature is high, and sometimes there is welding slag on the surface. Concentrated etching can also damage the surface of parts due to heat concentration. Nitrogen etching is bright and does not damage the surface. It can be used to etch instructions with high requirements.
Oxygen cutting has large thickness and low cost. It is mainly used in carbon steel. The cooling and protection of nitrogen improves the cutting quality, and has achieved good results in cutting stainless steel, aluminum and brass, and solved many processing problems.
In addition, it can be used to process wood, plexiglass and other special materials without auxiliary combustion, which has a broad application prospect.
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1. Conventional preparation method of nitrogen
1.1 nitrogen production by deep cooling air separation
Nitrogen production from cryogenic air separation is a traditional nitrogen production method, which has a history of nearly decades. It takes air as raw material, after compression and purification, and then uses heat exchange to liquefy the air into liquid air. Liquid air is mainly a mixture of liquid oxygen and liquid nitrogen,
The boiling points of liquid oxygen and liquid nitrogen are different (at 1 atmospheric pressure, the boiling point of the former is -183 ℃, and that of the latter is -196 ℃), and they are separated by liquid-air rectification to obtain nitrogen.
1.2 nitrogen production by membrane air separation
With air as raw material, oxygen and nitrogen can be separated by different permeation rates of gases with different properties such as oxygen and nitrogen in the membrane under certain pressure. Compared with other nitrogen making equipment, it has simpler structure, smaller volume and no switching valve
It has the advantages of less maintenance, faster gas production (≤ 3 minutes) and convenient capacity increase. It is especially suitable for small and medium-sized nitrogen users with nitrogen purity ≤ 98%, and has the best function price ratio. When the purity of nitrogen is above 98%, it is the same as PSA of the same specification
The price of the machine is more than 15% higher than that of the machine.
1.3 PSA PSA nitrogen production
Pressure swing adsorption (PSA) is a new gas separation technology. Its principle is to separate gas mixtures by using the difference of "adsorption" properties of molecular sieves for different gas molecules.
At present, carbon molecular sieve or zeolite molecular sieve is widely used in the field of nitrogen and oxygen production. The separation of oxygen and nitrogen by molecular sieves is mainly based on the different diffusion rates of the two gases on the surface of molecular sieves. Carbon molecular sieves are both activated carbon and molecular sieves
Carbon based adsorbents with certain properties. The carbon molecular sieve has a very small micropore composition, and the pore size distribution is between 0.3nm ~ 1nm. The gas (oxygen) with smaller diameter diffuses faster, and more of it enters the solid phase of molecular sieve, so that nitrogen can be enriched in the gas phase. a section
After a period of time, the adsorption of oxygen on the carbon molecular sieve reaches equilibrium. According to the different characteristics of the carbon molecular sieve on the adsorption amount of adsorbed gas under different pressures, the pressure is reduced to remove the adsorption of oxygen on the carbon molecular sieve. This process is called regeneration. PSA usually uses two towers in parallel,
Pressure adsorption and decompression regeneration are performed alternately to obtain continuous nitrogen flow.
Note: China GMP nitrogen is not managed as a drug, but the United States and the European Union include nitrogen in the Pharmacopoeia.
3. Nitrogen system verification
1. equipment inspection
2. component installation inspection
3. instrument calibration and inspection
4. media supply inspection
5. equipment installation inspection
6. material inspection of contact products
7. control system installation inspection
8. spare parts inspection
9. filter inspection
3.2.1. Pre confirmation requirements
Test instrument inspection
3.2.2 operation confirmation inspection
Mechanical function inspection
Automatic control function inspection
Confirmation of operating parameters
Noise test and EHS confirmation
3.3 PQ (according to QS, TS)
1. Microorganisms, particles, moisture and others
2. Purity (non oxygen content, oxygen content)
3. Pressure and pressure stability test
"Many efforts have been made to optimize and improve the mechanical properties of AM components by investigating various process parameters, scanning strategies and building orientation effects." "The introduction of shielding gas is another
An important parameter, which affects not only the thermophysical properties of manufacturing parts, but also the mechanical properties of manufacturing parts. The shielding gas is responsible for removing the active gas around the molten pool to prevent adverse effects caused by reaction with the atmosphere
Ring. When selecting a suitable shielding gas for a gas such as oxygen, various factors must be considered, such as the basic material of the gas and the molten pool and the chemical metallurgical reaction.
The effects of various shielding gases such as nitrogen, argon and helium on the behavior of carbon steel, stainless steel and aluminum alloy were studied. The research focus of the researchers is "through simulation under typical l-pbf conditions
A single track is used to simulate the thermal response of 17-4 PH SS, while considering the convective heat transfer of different shielding gases ". A numerical study was carried out to obtain the
Temperature, temperature gradient and cooling rate of manufactured parts. Microhardness test and tensile test were carried out to determine the mechanical properties of 3D printing parts under different shielding gases. The following conclusions are drawn:
1. Nitrogen atmosphere introduces slightly lower temperature and temperature gradient along the orbit, and the cooling rate is higher than that of argon atmosphere. The researchers attributed this to the high thermal conductivity of nitrogen.
2. When nitrogen is used as a shielding gas, more energy should be dissipated from the track to the environment. This is due to the higher cooling rate provided when nitrogen is used.
3. The hardness of the samples manufactured under nitrogen shielding gas is slightly higher than that of the samples manufactured under argon. This is due to the finer microstructure obtained due to the higher cooling rate provided in the nitrogen atmosphere.
4. "The hardness of HT AR / AR sample is higher than that of HT AR / N2 sample. This is because the austenitic matrix manufactured in argon atmosphere has higher precipitation hardening ability than martensitic microstructure.
The change in tensile behavior was minimal under all test conditions. However, the samples 3D printed in nitrogen atmosphere have slightly higher strength and ductility.
This study can provide valuable insights to better avoid adding defects in manufactured parts, such as porosity and lack of fusion. In particular, the manufacture of metal additives is a very accurate science, involving a large number of
To create the best conditions for 3D printing. According to the research of researchers, manufacturers may be able to change the conditions of 3D printed parts to obtain better overall components.
GSE technology is an innovative technology company, which can provide high-performance nitrogen generator for 3D printing industry to meet the nitrogen demand of the industry.
Today, GSE Tech （Suzhou） Co., Ltd. officially welcomed the first "plaque" awarded by the government since the establishment of the company - a private technology enterprise in Jiangsu Province.
It means that GSE's R & D and innovation in the field of gas generators have been affirmed.
Thank you for your support. We will continue to work hard to provide you with a better and more convenient gas generator.
Did you choose the right nitrogen for selective wave soldering? In the nitrogen protection system, there are several sources of nitrogen: pipeline nitrogen, liquid nitrogen, gas cylinder, nitrogen generator, etc. For most manufacturers, there is no such unique and excellent condition as pipeline nitrogen, and some people will choose liquid nitrogen and gas cylinders; In the early stage of these two options, although the investment will be small, there will be more logistics problems, suppliers' market supply problems and so on. For a long time, it is not a small investment. Therefore, the nitrogen generator is a reasonable choice, and the one-time investment return cycle is short!
GSE Technology (Suzhou) Co., Ltd. (hereinafter referred to as GSE) is an innovative technology enterprise, committed to professional innovation and service of industrial gas frontier technology. We focus on scientific and technological research and development, provide customers with more comprehensive, convenient and considerate services, and constantly pursue innovative products and improve service models to create higher value for customers.
As the latest generation product independently developed by GSE, the modular nitrogen generator is made of aviation aluminum magnesium alloy, and the principle is pressure swing adsorption technology. At the same time, it absorbs the product advantages of membrane separation. Its excellent nitrogen quality and plug and play convenience are easier to be accepted by customers.
Moreover, the modular nitrogen generator of our company is compact in structure and small in volume, and the adsorption barrel meets the national standard non pressure vessel, so as to avoid the complicated and unnecessary additional work such as the annual national declaration of enterprise pressure vessel. Our modular nitrogen generator ranges from 97%-99.999% purity and 1.0-114.1m 3 The hourly air supply flow is available for customers to choose. Our equipment has an intelligent control system without special personnel and 7x24 hours of non-stop supply of nitrogen to better cooperate with the work of selective wave soldering!
Another feature is that our machine has the CMS module expansion function. If the customer adds a furnace in the later stage, there is no need to worry about insufficient nitrogen. Just add a CMS module directly! Save customers' purchase cost.
This is a case we provided for our customers. We can see that our machines are very coordinated at the side of the furnace and will not occupy additional space in the plant! GSE we always take the customer's demand as our biggest goal to improve the welding quality! GSE - your nitrogen making expert!