威廉希尔官方下载May 06, 2020
With the development of film technology, various kinds of non-metallic films have been widely used in military-industrial products and 3C electronic products. The non-metallic film products can be used for shielding seal, waterproof seal, heat conduction, insulation, appearance decoration, appearance protection, etc. the thickness of these films is generally between 0.1mm ~ 2mm, and the application scenarios are different in shape and shape. Due to the limitations of traditional manufacturing methods, such as cutting tools or mold forming, laser cutting has been widely used in non-metallic film-forming.
The output wavelength of CO2 laser is 10.6um, and the absorption rate of non-metallic film is higher than that of other wavelengths. Therefore, CO2 laser is preferred for film processing and forming. The basic way of CO2 laser processing film is to expand the laser beam, then focus on the film products, the materials in the focus are gasified instantly, so as to achieve the cutting of materials, and finally get various shapes of film products. There are two kinds of common CO2 laser processing equipment: galvanometer scanning processing equipment and flying optical path scanning processing equipment. The RF excited diffusion cooled slab waveguide CO2 laser has become the preferred laser in thin-film cutting and forming due to its advantages of good beam quality, high peak power, maintenance-free and small volume.
威廉希尔官方下载ing the RF CO2 laser cutting and forming equipment to produce film products has the following advantages:
Computer graphics, no mold - cost saving, fast response to market demand, can not only small-batch proofing, but also mass production; WYSIWYG - low-quality requirements for operators, saving labor costs; maintenance-free, no consumables - saving time, labor, cost.
PET mobile film
Film processing products shall have a neat edge, no sawtooth, small heat affected area, small cutting slope, and no residue accumulation on the edge. There are many factors that affect the processing effect of RF CO2 laser processing equipment. The following is a qualitative analysis of the factors that affect the film processing effect:
The RF CO2 laser has four wavelengths: 10.6um, 9.3um, 10.2um, and 9.6um. Most of the non-metallic materials are organic plastic products and polymer products. The absorption rate of organic materials is very sensitive to the change of light wavelength, and the absorption rate difference is very large due to the small difference of wavelength. The difference of material's absorptivity has a fundamental influence on the processing effect, so the choice of wavelength is the first one that affects the processing effect, and these four wavelengths can be reliably obtained by commercial RF CO2 lasers. The laser has a maintenance-free service life of more than 20000 hours. After simple inflation, it can be used again. The reasonable maintenance of the RF CO2 laser has a lifetime of more than 100000 hours.
The output power of the RF CO2 laser varies from a few watts to a kilowatt. According to the thickness of thin-film cutting, cutting speed and material absorption, select the appropriate power and laser. Generally, the CO2 laser power used in cutting is not more than 80% of the maximum output power of the laser, which is easy to get the best performance and effect.
Focal length of focusing lens
The focal length of the focusing mirror directly affects the size of the focus spot, so it is very important to choose the appropriate focal length of the focusing mirror. Flying light path cutting equipment, the focal length is generally between 1 inch and 2.5 inches. For the same focal length, there are a Plano-convex lens and a meniscus lens. Generally, the focus spot of the meniscus lens is smaller than that of Plano-convex lens. For CO2 Laser Galvanometer Scanning processing equipment, the focal length of the focusing field mirror is generally 80-160mm; for galvanometer scanning processing equipment with special fine effect requirements, far center scanning field mirror is required.
Film cutting speed
The cutting speed determines the laser processing time and the laser energy absorbed by the film material, and then affects the size of the cutting heat affected zone. The cutting speed of film cutting is usually greater than 100 mm / s in flying light path mode, and that of galvanometer scanning laser processing is generally greater than 500 mm / s. If the cutting speed reaches several kilometers per second, pay attention to the combination of laser modulation frequency and speed to get a smooth edge.
Although the film is very thin, it also has a certain thickness. The focus position is on the upper surface, the middle of the material, the lower surface of the material, even the upper defocus and the lower defocus. The choice of different focus positions can affect the machining efficiency and machining effect.
The laser mode describes the distribution of laser energy in the cross-section of the laser beam perpendicular to the direction of transmission. The laser mode is divided into transverse mode and longitudinal mode. Most of the RF CO2 lasers are transverse mode. In the application, the RF CO2 laser mode is simply divided into the fundamental mode and multimode mode. In order to obtain a fine processing effect, the fundamental mode spot is often selected. The beam quality factor M2 of the base mode output laser is relatively small, generally less than 1.5. According to the calculation formula of focus spot.
Spot is the diameter of the focus spot, λ is the laser wavelength, f is the focal length of the focus lens, and D is the size of the spot incident on the focus lens. It can be seen from the calculation formula that the focus spot size is directly proportional to the beam quality factor M2. So choosing the basic mode and the laser with small beam quality factor can get the small focus spot and better machining effect.
The auxiliary gas can blow away the smoke produced at the incision; prevent the waste residue and smoke from polluting the optical mirror; guide the laser thermal energy, so that the laser energy can act on the material more intensively, and enhance the laser cutting ability. According to the cutting needs, combustion supporting or flame-retardant gases can be selected.