Laser cutting of metals and other materials.
Laser cutting is a cutting process of materials (primarily metals and alloys) using a focused laser beam of high power, which will be carried out by means of a computer.
Laser cutting is a cutting process of materials (primarily metals and alloys) using a focused laser beam of high power, which will be carried out by means of a computer. Since the beam has a high concentration of energy, it is able to cut almost any materials. When running processes there are various chemical and physical processes that depend on the thermophysical properties used for the work material. This allows you to get a completely smooth edge, not requiring further processing, and diverse, including narrow and thin cuts.
When cutting with a laser is almost not possible mechanical effects on the material used, and it virtually eliminates the likelihood of deformations and marriage during the production process, and after final reduction of the temperature of the product. All this allows to apply the technique in thin, brittle materials, easily deformed and “not tolerate” other similar types of exposure.
Today laser cutting is one of the efficient ways of cutting, cutting and processing a variety of materials. With its help it is possible to obtain products of the highest quality, and in record time, allowing you to use it in a variety of industries and production. As practice shows, laser cutting is the leader among other similar methods of treatment, her inferior waterjet, milling and plasma even, so finding it a worthy replacement is impossible today.
For the process of laser cutting today use three types of laser that can operate continuously and in pulse-periodic mode:
– solid state;
Most preferred is the latest type of equipment (installation of the gas (CO2) lasers), as its operating costs by half lower than when using the other.
It is worth considering that completely replace laser cutting and other methods of processing and cutting of materials is not yet possible, because the cost of such equipment is quite high. However, almost all industry are trying to use this technology, especially in situations where the use of other modes of production faces too time-consuming jobs, significant costs, or not possible to get such a high quality product.
A separate and important parameter of industrial laser systems used for laser cutting of materials is considered to be the consumption of electricity. It depends on the efficiency of the laser. Another important parameter of laser cutting are the power of the laser beam and its other specifications, which affect the quality of the manufactured products as well:
– type of processed materials, which are exposed to the laser. Spent less energy when processing materials with low thermal conductivity, as it is in this case concentrated in a smaller volume of source code, otherwise possible occurrence of grat – excess metalextruded during heat treatment;
the thickness of the sheet. For each material there are different options of pressure support (cutting) gas, which is used together with a laser beam, and the maximum thickness of the sheet;
– the rate and duration of exposure. The longer the device works, the more products it produces, the higher its production depreciation;
the environment where treatment is carried out – humidity, dust, temperature and other conditions.
For each material the cutting process by the laser has its own little nuances and differences. All methods of laser cutting involves the use of gas, which is nitrogen, oxygen or air, which allows it to reduce the specific energy consumption.
Laser cutting of metals:
Most often the laser is used for treatment of these or those metals or for cutting the necessary products from them. As in other thermal cutting methods (plasma or flame), it requires the effect of additional energy, but in this case this energy is a very focused laser beam. Focusing is performed by means of lenses, fixed in the cutter head, which ensures the melting of the metal. Depending on the thickness of the material, the beam can lead to evaporation (if the metal has a thickness less than two millimeters) or fusion (thicker product). To clean cutting of metal, subjected to heat treatment, is fed gas under pressure, which is called the cutting or the subsidiary. In most cases, this gas is either nitrogen or oxygen.
Carbon steel is subjected to laser exposure using only oxygen. The pressure with which the gas will be supplied, is inversely proportional to the thickness of the workpiece: the thicker, the lower the impact. Due to this dependence the properties of the material on the thin to 3 mm, the sheets of carbon steel, the removal of the thread the straightened material is mechanical, it is “squeezed”. Therefore, the maximum pressure in this case must not exceed 5 bar (4,93 MPa).
When processing leaves, whose thickness exceeds 6 millimeters, the effect of the laser leads to the burning material in an oxygen atmosphere (oxidation), i.e. there is a peculiar effect of flame cutting. To the process went well, the flow of gas save on average up to half of the bar (0,49 bar). The fact that the pressure for thick carbon steel sheets should be as low as possible, imposes a limit on their processing – laser cutting possible products, whose thickness does not exceed three inches.
Main auxiliary gas laser cutting machine for stainless steel is the nitrogen, but in some cases it can be replaced by ordinary air. Cutting under the influence of these gases produces smooth, accurate cuts without the presence of oxide tints or scale. The choice between air and nitrogen depends on the quality requirements of the cut: if you want perfect condition, it is better to choose gas, otherwise, fit the air, especially if the steel is thin (up to two millimeters).
The pressure of a gas is directly proportional to the dependence on the plate thickness: the thinner, the lower the degree of the impact. The maximum pressure exerted on the stainless steel, should not exceed 15 bar (14,8 bar). This feature directly affects the cost of laser cutting products having a considerable thickness, because it requires a lot of nitrogen. The maximum thickness of stainless steel sheets that is capable of handling modern equipment, is 30 millimeters.
Aluminium and alloys on its basis are the most difficult for laser technology. The technique is applied to the material and its parameters is completely analogous to the cutting of stainless steel. Exception – maximum sheet thickness, it is 20 millimeters.
Laser technology is not accidental considered the undisputed leader among the other methods of cutting and machining. This is confirmed by their advantages:
– higher machining accuracy. To have an almost perfect product perhaps even in plants with reduced positioning accuracy of the cutting head, and using modern and advanced equipment, the error is practically absent, which allows to obtain a higher accuracy of the location of any, even the most minor items, on details;
– high-speed processing. Due to the rapid movement of the sheet of material to be processed is the difference between laser cutting and mechanical processing method can reach 1000 times.
– the absence of mechanical impact. It is reduced to almost zero, and this gives you the ability to cut and handle products of their fragile, easy to fracture and deformation of materials;
– low thermal impact. All other thermal processing methods differ significant thermal effects, and laser cutting, this parameter is minimal. This allows you to work with products prone to warping, having a decorative coating, painting and so on. An important caveat is the thermal conductivity of materials, which may slightly affect the quality of the result;
– the possibility of obtaining complex products. This option became possible due to the negligible small diameter of the laser beam from 0.15 to 0.25 millimeters. Such precision and delicacy gives you the ability to cut holes of very small sizes to all types of cross sections, complex curved sections, etc.;
– automation. Since the control laser beam is performed with a computer, you can set the options necessary details in any drawing program and obtain the product of any complexity. Also, automation allows the control of work and timely diagnosis of the condition of the equipment without any additional efforts on the part of the person;
– the possibility of remote processing, for example by controlling the laser remotely in the next room
– selective effect, i.e. the effect only on a certain side of the product;
– high performance laser cutting. She gives not only mechanical effects but also all other known methods of cutting and cutting of materials;
– high quality of the cut surfaces – perfectly smooth cuts, high accuracy of processing, absence of seams, and so on;
– easy control of the process cutting regardless of the complexity of manufactured parts, because almost all work is done by a computer;
– the possibility of both flat and volumetric products.
Laser cutting allows to process and obtain high-quality products of the following (in parentheses indicate the maximum thickness of the sheet):
– carbon steel (30 mm);
– stainless steel (30 mm);
– armor steel (25 mm);
– aluminium (20 mm);
– copper (5 mm);
– brass (5 mm);
– Titan (5 mm);
– galvanized steel (4 mm),
– wood, plywood,
– fabric, leather.
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