The role of oxygen in the cutting process of carbon steel is to fuel and blow off the molten material. （3）In order to extend the application of engineering machinery and shipbuilding industry, the thickness of low carbon steel has exceeded 30mm. Special attention is paid to the study of the technology of nitrogen cutting low carbon steel to improve the cutting quality of the plate. The cutting speed can reach 600cm/min for 2mm mild steel with 1200W laser cutter while the speed can reach 1200cm/min for 5mm Polypropylene resin plate. The material does not need to be clamped in the laser cutting, which can save not only the tooling but also the auxiliary time of loading and unloading materials. The inherently high speed of laser processing combined with the ease of high-speed automation and elimination of most post-processing steps provide significantly shorter cycle times than competing technologies.
With the relative linear movement of the beam and the material, the hole is continuously formed into a narrow slit. The material is quickly heated to the degree of vaporization, and the pore is formed by evaporation. It is also not easy to achieve success by cutting a very large and closed shape. It is important to note that this controlled fracturing cutting is not suitable for cutting acute angle and arm of angle. With the moving of the workpiece, the hole is synchronized horizontally to form a slit in the direction of cutting. In the vaporization process, about 40% of the material is dissolved into steam, while 60% of the material is expelled by the flow in the form of a droplet.
After the device is adopted, the cutting data can be received from the computer-aided design workstation. The maximum thickness of cutting can be increased to 16mm, but the size error of the cutting part is larger. ⑵ Optical fiber laser has a small volume, light weight, movable and flexible working position. In addition, the fiber laser generator has no vulnerable parts, and there is no late maintenance cost.
When cutting flammable materials such as cotton, paper, the inert gas is been used. As long as the balanced heating gradient is maintained, the laser beam can guide the cracks in any desired direction. The laser beam heats the small area of the brittle material, causing the large thermal gradient and serious mechanical deformation in the region, causing the material to crack. It is estimated that when the steel is cut, the amount of heat released by the oxidation is about 60% of the total energy required for cutting.
The sample in the laser cutting sample FIG was cut with a high purity of 99.99% pure liquid nitrogen, and the gas pressure was 0.8 ~ 1.0mpa. The role of nitrogen in the stainless steel cutting process is to eliminate oxidation and blow off the melt. When the optimum cutting speed is reached, the surface roughness of the cutting section is the minimum. The cutting speed shows the parabolic relationship with the surface roughness of the cutting section. When cutting aluminum alloy, the focal position is close to the lower surface of the plate. The core component adjusts the curvature of the lens surface by water pressure, thereby changing the divergence angle of the laser beam, and finally adjusting the laser focus up and down movement.
Under this heat, the material is formed by a small hole filled with steam, surrounded by molten metal walls. Due to oxidation produced a large amount of heat in the process of cutting, so the energy needed of laser oxygen cutting is just 1/2 of molt cutting, and cutting speed is more than laser vaporization cutting and melting cutting. For example, when cutting stainless steel materials, when the requirement for the quality or surface quality of the products is not high , air can be used as the cutting gas, which can reduce the cost. The laser power has a great influence on cutting thickness, cutting speed, cutting width and cutting quality. In the process of laser cutting, the laser focus position has a great influence on the surface quality of the parts after cutting, and different materials have different requirements on the focus position. It is now common for these systems to perform multiple laser operations, including cutting, welding, drilling and marking, using one machine on a single part or family of parts.
The thicker the plate thickness, the higher the pressure value of nitrogen work. When cutting stainless steel, the required purity of nitrogen is generally higher than 99.999%. Low purity nitrogen can lead to yellowing of the cutting surface and lower brightness. Nitrogen is usually used for cutting stainless steel and aluminum alloy materials. It is important to note that the oxygen contains impurities such as water, which can seriously affect the cutting quality of the plate surface.
It is also a lot more flexible, allowing the user to modify hole size, shape, and approach angle while maintaining repeatability and quality. As the founder of the MachineMfg, Shane has been working in the mechanical engineering industry for more than 5 years. He loves writing and focuses on sharing technical information, guidance, detailed solutions and thoughts related to metals and metalworking.
Laser fusion cutting is mainly used for the cutting of non-oxidizable materials or active metals, such as stainless steel, titanium, aluminum and alloys. Therefore, in the process of cutting materials, it is necessary to select the auxiliary gas according to the characteristics of the product. The laser processing of different materials requires the use of matching auxiliary gases. The auxiliary gases commonly used in laser cutting are nitrogen, oxygen and air. Under certain plate thickness and cutting speed, there is an optimal range of laser power. During the cutting process, due to the uneven surface of the material, the focal position of the laser will change, thus affecting the cutting quality.
From a practical standpoint, the use of beam delivery fiber expands integration options and facilitates the use of the laser in the manufacturing environment. Also, the high reliability, excellent uptime and favorable cost of ownership characteristics. In a fiber laser, the laser light is generated in an active fiber and guided to the work piece by means of a flexible delivery fiber, which acts as a “light guide”. In contrast, the Pulsed Fiber lasers deliver a pulse of energy which is typically ten to twenty times higher than their average power.
Generally, the required pressure is 0.3-1Mpa, and the flow rate varies according to the thickness of the cutting material. For example, cutting 22mm carbon steel, the flow rate should reach 10m3/h (including the protection oxygen of the double-nozzle). While the oxygen reaction heat is used to increase the cutting efficiency, the resulting oxide film increases the beam spectral absorption factor of the reflective material. Therefore, the higher the air pressure value used, the faster the laser cutting speed can be. It can blow the cutting piece be melted and vaporized, can also blow the smoke in the process of cutting, so as to reduces the barriers to cutting the workpiece. In addition, the NC system can automatically adjust the cutting power according to the cutting speed.
Install it on the die-cutting machine to cut off a variety of printed graphics boxes. Stainless steel used for decoration, advertisement, service industry or patterns, marking and font of non-metallic materials . Such as the pattern of an art photograph album, Chinese and English fonts of the company, government department, the hotel, the shop sign, the station, the pier, the public place. Cutting torch during laser cutting has no contact with the workpiece and no tool wear. The machining of parts with different shapes does not require replacement of the “cutter”. The laser cutting process has low noise, small vibration and no pollution.
The pressure and flow rate are different, which is inseparable from the size of the nozzle model and the thickness of the cutting material. Mainly used for rolling steel, rolled steel for welding structure, carbon steel for mechanical construction, high tension plate, tool plate, stainless steel, electroplated steel sheet, copper, copper alloy, etc. If oxygen purity is not high, and the processed parts have higher surface quality requirements, it is necessary to add oxygen drying and other devices to improve the purity of oxygen. Fiber Laser cutting equipment is very expensive, but it is still possible to use the device in large production because of the lower cost of subsequent processing. However, when oxygenated, a thin oxide film is formed on the cutting surface. At the same time, it has a better cutting effect for high reflective material such as aluminum alloy, copper, copper and various copper alloys.
Based on the characteristics of the gas, such as flammability and combustion, and various attempts, the following experience is obtained. Further increase or decrease in power will result in a burning or slagging defect. Compensation for focus changes due to different spot diameters at different working positions of the machine. The laser is a kind of enhanced light obtained by stimulated radiation. With the next generation of all-in-one mobile devices well on its way, it is lasers that are driving innovation for each and every component. Different kinds of joints require different operation modes of the laser device.
For example, the laser cutter with 2KW laser power been adopted, the cutting speed of carbon steel with 8mm thickness is 1.6m/min. The cutting speed of stainless steel with 2mm thick is 3.5m/min, and the thermal influence area and the deformation are very small. When the laser power and the auxiliary gas pressure are certain, the cutting speed and the slit width maintain a nonlinear inverse relationship.