1. Laser Technology
the laser light source 20 is the new 1960s. Since the laser has a good direction, high brightness, good color and other characteristics are widely used laser laser processing is one of the most promising areas, and now has developed more than 20 kinds of laser processing technology.
Basic information of laser light having good color, strong direction, and high brightness. Laser materials has been found that there are thousands of species, from the soft X-ray wavelength range to the far infrared. The core technology of the laser is a laser, many types of lasers, various methods according to the working substance, the excitation mode, operation mode, etc. and the operating wavelength. Depending on the requirements, to take some special techniques to improve the quality of the output laser beam and the individual specifications, cell technology has widely applied resonant cavity design and mode selection, frequency, tuning, Q switch, mode-locked, frequency stabilization and amplification technology.
In order to meet the needs of military applications, the following five main development of laser technology: ① laser ranging technology. It is the first practical application of laser technology to get in the military. The late 1960s, a laser rangefinder start troops, been developed to produce a variety of types, mostly using YAG laser ranging accuracy plusmn; 5 meters. Because it can quickly and accurately measure the target distance, widely used in measuring and reconnaissance weapon fire control systems. ② laser-guided technology. High-precision laser-guided weapons, the structure is relatively simple, less susceptible to electromagnetic interference, it plays an important role in precision-guided weapons. Early 1970s, the United States developed a laser-guided bombs first used in the Vietnam War. Since the 1980s, the production of laser-guided missiles and laser-guided artillery shells and quantity of equipment is also increasing. ③ laser communication technology. Laser communications capacity, good security, anti-electromagnetic interference. Optical fiber communication has become the focus of development communication systems. Airborne, spaceborne laser communications systems and laser communication systems for submarines is also studying development. ④ strong laser technology. Tactical laser weapons made of high-power lasers, can the human eye and blinding lightElectrical detector failure. High-energy laser beam could destroy aircraft, missiles, satellites and other military targets. For blindness, and other air defense tactical laser weapons, is close to the practical stage. For anti-satellite, anti-intercontinental ballistic missile strategic laser weapons, is still in the exploratory stage. ⑤ laser simulation training technology. Carried out with laser simulators for military training and combat exercises, do not consume ammunition, safety training, the effect is real. It has been developed to produce a variety of laser simulation training system, widely used in fire training exercises and combat all kinds of weapons in. In addition, laser fusion research has made significant progress in laser isotope separation into trial production stage, laser fuses, laser gyro has practical application.
Laser Laser principle:
laser English full name is Light Amplification by Stimulated Emission of Radiation (LASER). Came out in 1960, it is a result of radiation and stimulate the production of reinforced light.
scientists electrical energy to light or tube current to certain crystals or impact excitation of atomic species are susceptible, it reaches a high atomic electrons excited energy state, when these electrons to return to calm the low-energy state, the atoms emit photons to release excess energy; and then, these are emitted photons will strike other atoms, excited atoms to produce more photons, triggering a series of “chain reaction”, and both a forward towards the same side, and form a strong concentration of light toward a certain direction; thus even intense laser cutting can be used as steel!
The laser characteristics:
the laser light is widely used because of its characteristics. Almost a monochromatic wave laser, a very narrow frequency range, but also a high energy concentrated in a narrow direction, the laser beam can be focused after puncturing by a variety of materials. Ruby lasers, for example, that the total energy of the output pulse of a boiled egg is not enough, but it can drill a small hole in the steel sheet 3 mm. Laser has the above characteristics, not because it has a light with a difference, but it’s a very high power density, which is why lasers are widely used.
Laser following three features:
monochromatic wavelength
coherence
parallel light beam
the laser Laser Processing:
Spatial and temporal controllability well controlled laser, the material of the object to be processed, the shape, size and processing environment consisting of degrees are great, especially for automated processing. Laser processing systems and computer numerical control technology may constitute a highly efficient automated processing equipment, it has become a key technology companies to implement timely production of high-quality, high efficiency and low cost of processing opens up broad prospects.
can be applied hot and cold metal and non-metallic materials, cutting, drilling, grooving, tags, etc. for hot working a metal material welding, surface treatment, production of alloys, are very favorable cutting. cold working of the photochemical deposition, laser rapid prototyping technology, laser etching, and the dye-doped oxide are suitable.
Rapid Prototyping:
for producing laser model with a liquid photosensitive resin is a material which absorbs the laser energy in the ultraviolet range after solidification occurs, is changed to a solid material. The program compiled model to be manufactured, entered into the computer. Laser output of a laser beam controlled by a computer optical system, scans on the scoring model material, wherever the laser beam, originally liquid material freezing up. Directing the laser beam has been scanned scored mainly as a computer, the cured photopolymer material layer by layer, stacked in precise sample, create the model. Therefore, the model manufactured in this way, fast and sophisticated model made out of. The technology has been widely used in industrial fields of aerospace, electronics, automotive and so on.
Laser cutting:
technology is widely used in laser cutting of metal and non-metallic materials, it can significantly reduce processing time and reduce processing costs and improve the quality of the workpiece. A pulsed laser for metal materials, non-metallic materials suitable for continuous laser, which is an important field of application of the laser cutting technology. However, application of laser in the industrial field is to have limitations and shortcomings, such as a laser to cut food and plywood is not successful, the food is cut while also burning, while the cutting of plywood is far from substandard count on economic .
With the rapid development of laser industry, laser technology and laser-related products are becoming increasingly sophisticated. In the field of laser cutting machine, currently showing a solid-state YAG laser cutting machine,CO2 laser cutting machine for their feet, fiber laser cutting machine from behind the situation.
YAG solid-state laser cutting machine has a low price, good stability, but the energy efficiency is generally low lt; 3 percentages, most of the current products in the output power of 600W or less, since the output energy is small, is mainly used for making spot and cutting the hole and the sheet. It is a green laser beam can be applied in the case of pulsed or continuous wave having a wave length, condenser and good machining precision especially suitable for hole processing is most effective in a pulse, can also be used for cutting, welding and lithography . YAG solid laser wavelength of the laser cutting machine can not easily be absorbed non-metallic, non-metallic materials it can not be cut, and a YAG solid laser cutting machine to be solved is to improve stability and lifetime of the power supply, i.e. to the development of optical pumping large capacity, long life an excitation light source such as a semiconductor optical pump allows a considerable increase in the energy efficiency.
CO2 laser cutting machines, steel cutting can be stabilized within 20mm stainless steel less than 10mm, 8mm or less aluminum. CO2 laser wavelength of 10.6um, more easily absorbed non-metallic, high quality cutting can be wood, acrylic, PP, glass and other non-metallic materials, but the CO2 laser photoelectric conversion rate is only about 10 percentage. CO2 laser cutting machine at the outlet of the light beam with blowing oxygen, air or an inert gas nozzle N2, to improve the cutting speed and cut flat and smooth. To enhance the stability and longevity of the power source, for CO2 gas laser discharge stability to be Solved by the high power laser. According to international safety standards, Laser Hazard rating grade 4, CO2 laser belong to the least harmful level.
Since the fiber laser cutting machine which can be transmitted through the fiber, the degree of flexibility than ever before, less the point of failure, easy maintenance, is fast, so when cutting the fiber sheet within 4mm cutter has a great advantage, ; however, it is affected by the poor quality of solid-state laser wavelength when cutting thick plate. Fiber laser wavelength of laser cutting machine 1.06um, can not easily be absorbed non-metallic, non-metallic materials it can not be cut. Fiber laser photoelectric conversion rate up to 25% or more, in terms of electricity consumption, complete cooling system are obvious advantages of a fiber laser. According to international safety standards, Laser Hazard Class 4 rating, because the short wavelength fiber laser on the human body because it is big damage to the eyes,Belonging to the biggest hazard level, for security reasons, the fiber laser processing needs fully enclosed environment. Fiber laser cutting machine as a new laser technology, penetration far less CO2 laser cutting machine.
Laser Welding
the laser beam is irradiated on the material, which will heated to melting the components butted together are joined together, i.e. welded. Laser welding, with less than the cut metal power laser beam, without molten material vaporized, after cooling becomes a continuous solid structure. Laser welding technique has purifying effect of the bath, can clean weld metal, for welding between the same and different metal materials. Due to the high laser energy density, high melting point, high reflectivity, high thermal conductivity and physical properties differ greatly advantageous particularly metal welding. Because by laser welding does not require any solder, it is ruled out contamination welded assembly;
Next, the optical system of the laser beam can be clustered into very small beam diameter, in other words, the laser can be made very fine the torch, precision welding work to do; there are laser welded components are not in direct contact with, that this is a non-contact welding, material fragile and therefore does not matter, you can also away from the components around us as welding, can also put placed in a vacuum chamber assembly welded. Because the laser welding of these features, so it is especially popular in the microelectronics industry.
Laser engraving:
used as the laser engraving burin, more convenient than with ordinary chisel more quickly. Ordinary chisel in hard materials, such as carved in granite, steel, or in some relatively soft material, such as leather engraving, it is more difficult, an engraved pattern takes a long time . If a laser engraving is different, because it is the use of high energy density laser illumination of a workpiece, the surface layer material gasification or chemical reaction color change, thereby leaving a permanent method of engraving marks. And it does not have contact with the material, a hard or soft material, it does not prevent engraving speed. So laser engraving laser processing technology is one of the largest applications. In this chisel for carving whether in hard materials, or on a soft material carving, scoring the same speed. If it cooperates with the computer, controlling the laser beam moves, carvingWork can also be automated. The pattern to be engraved on the photoelectric scanner, the scanner output signal after computer processing, for controlling the operation of the laser beam, can automatically be in the wood, glass, leather carved out according to our pattern. Meanwhile, the focused laser beam up and is very small, equivalent ambidextrous chisel, engraving fine lines, a pattern detail can be carved out to. Laser engraving can play a variety of text, symbols, patterns and the like, a character size can be on the order of from micrometers to millimeters, which have special significance for security products. Laser engraving is Pat development in recent years to achieve sub-micron engraving, it has been widely used in the microelectronics industry and bio-engineering.
Laser Drilling:
to open a small hole in the assembly is a very common thing. However, if desired on a hard material, such as playing a large number of pores 0.1 mm in diameter to several microns on a cemented carbide. Ordinary machining tool is probably not easy to do, even if they can do it, processing costs will be high. Laser has good coherence, optical system it can be focused to a spot diameter of a marginal (less than one micron), which is equivalent to a micro drill used for drilling. Secondly, the high brightness of the laser, the laser energy density (on the average energy per square meter area) focused on the focal point will be high, a normal laser output of the laser, the energy produced can be up to 109 J / cm 2 enough to allow the material to melt and vaporized, leaving a small hole in the material, like a drill bit out. However, laser-drilled hole is conical, cylindrical rather than mechanical drilling, which in some places is very convenient.
Laser etching:
the laser etching technique simpler than conventional chemical etching process, which can greatly reduce the production cost, processability 0.125 to 1 micron wide lines, very suitable for VLSI producing circuit.
Development of laser surgery laser:
capable of producing a high energy laser ﹑ precise focusing monochromatic light having a certain penetration, can produce high localized heat when applied to human tissue. Laser surgery is the use of this feature of the laser, remove or destroy the target tissue for therapeutic purposes. Including laser cutting and laser resurfacing.
Laser Weapons:
laser weapon has its uniqueness, so it is widely used anti-aircraft, anti-tank, self-defense and other military applications laser bombers has become a powerful weapon, because it has three levels of destructive power:
1. ablation of laser thermal processing with the same principle, when a high energy laser beam incident on the target, the laser energy is absorbed by the target material is converted to heat. This heat is sufficient to make the target partial or complete perforation, fracture, melting, evaporation, or even an explosion.
2. the effect of shock target material is vaporized, the target material generates backlash in a very short time, the surface of the material to form a compression wave spallation broken open, when causing further damage debris flying outwardly.
3. the radiation effect will also vaporized target material to form a plasma cloud, and capable of producing ultraviolet radiation and X-rays, the inside of the target electronic component is destroyed.
Laser energy:
may also be used in nuclear power laser. The world is now built nuclear fuel used in nuclear power plants is uranium, tritium studies using nuclear fuel has not been successful. Prepared from the Institute of tritium fuel to burn fuel more resistant than uranium, 1 kg tritium fuel combustion energy generated three times higher than the nuclear fuel. More attractive is the big tritium storage of nuclear fuel on Earth. 1 kg containing 0.03 grams of tritium in seawater, the oceans on Earth with a 1021 kg seawater; or that it is stored in the Earth’s oceans have 1017 kg of tritium, it developed out of fuel, the equivalent of 10 has provided us quadrillion (1017) tons of coal, enough for a human to spend hundreds of millions of years, since tritium nuclear fuel so good. Why not now? the problem is that it is not an easy ignition combustion do. Draw a combustion temperature can match the paper sheet, gasoline on fire, fire make this fuel, the temperature required million degrees. Laser is more likely to reach the ignition temperature of technology.