With the recovery of the global economy and the rapid development of laser technology, 3000 watt fiber laser cutting machine technology has been widely used in aerospace, rail transit, automotive manufacturing, sheet metal processing and other key industries. The advent of fiber laser cutting machine is undoubtedly an epoch-making milestone in the history of laser cutting.
As we all know, the light source is the most core parts of thefiber laser cutting machine, there is a problem worthy of our attention, that is: why can fiber laser as the light source of the cutting machine in a short time quickly occupy the market and is widely respected? To sum up, there are mainly the following points:
A fiber laser wavelength is 1070nm short, is 1/10 of the wavelength of CO2 laser, which is conducive to be absorbed by metal materials, so that it has a faster cutting speed in cutting carbon steel, stainless steel, and pure aluminum, brass and other high reflection materials than the traditional CO2 laser cutting machine.
Two, the beam quality is high, so as to achieve a smaller spot diameter, even in the longer working distance and deeper depth of focus, can still provide fast processing speed, greatly reduce the workpiece tolerance. Taking IPG 2KW fiber laser cutting machine as an example, the cutting speed of 0.5mm carbon steel can reach 40m/min.
Three, fiber laser is the lowest comprehensive use of the cost of laser, can save a lot of costs. The electric to optical conversion efficiency of the fiber laser is up to 30℅, which reduces the utility cost of electric energy and cooling. Taking the same power 2KW fiber laser and CO2 laser with liquid nitrogen cutting 2mm thick stainless steel as an example, the fiber laser saves 33.94 yuan per hour than the CO2 laser. According to the annual work of 7200 hours, the single electricity bill, a 2KW fiber laser saves up to 250,000 yuan per year than the same power CO2 laser; At the same time, the cutting speed of fiber laser is twice that of CO2, coupled with the cost savings of late maintenance and occupation, which makes the fiber laser cutting machine become the preferred sheet metal processing system for many manufacturers.
Four, the long pump diode life and maintenance free, so that the fiber laser has become the first choice of manufacturers.
The pump source of the fiber laser is a carrier-grade high-power single-core junction semiconductor module with an average failure free time of more than 100,000 hours. The single-core junction semiconductor module does not need water cooling and can easily be imported into the double-clad fiber with high efficiency, without the need for complex optical focusing and optical guide system. Single-core junction can produce the same high output power, higher beam quality, and longer running time as an array. Fiber laser active optical fiber core diameter is very small, to avoid the traditional laser with the thermal lens effect, the energy transfer is conducted in the optical waveguide, no discrete components, fiber Bragg grating in alternatives to traditional laser cavity mirror, a cavity, no need for adjustment and maintenance and other characteristics make the fiber laser in use process requires minimal maintenance.
Five, fiber laser has the characteristics of small size, light weight, compact structure, flexible light guide and easy to integrate into the motion system, which reduces the complexity of using a large cutting platform; These lighter components, with fewer components and lighter construction, can be moved at high speeds, reducing motion energy consumption while maintaining accuracy and saving the manufacturer significant floor space costs.
Six, fiber laser has ultra-high stability, in a certain impact, vibration, high temperature or dust and other harsh environment can still work normally, showing a very high tolerance.
It is because of the unique advantages of fiber laser that it will accelerate its expansion in the global laser cutting market. Since 1980, the number of thin plate laser cutting systems with high-power CO2 lasers as the light source has been approximately 50,000 units worldwide. The annual sales volume is about 3500-4000. Therefore, the market penetration of high power fiber lasers will set off a frenzy in the system supply field. First, fiber lasers are likely to steal market share from CO2 laser suppliers. In the eyes of high power CO2 laser suppliers, fiber lasers are becoming a growing and highly competitive competitor. Second, fiber lasers can expand the fiber cutting machine market by absorbing new system integrators who have not yet shown interest in CO2 lasers. Third, many of today's global companies with systems integration that supply flat cutters, when they encounter new competition, most take the step of adding optical laser products to their marketing mix; These three elements are driving the current laser cutting market change.
In the CO2 laser cutting machine for cutting precision higher or thicker parts, we must master and solve several key technologies. The focus position control technique is one of them. One of the advantages of laser cutting is the high energy density of the beam, so the focal spot diameter should be as small as possible in order to create a narrow slit. Because the smaller the focal depth of the focusing lens, the smaller the focal spot diameter, for high quality cutting, the effective focal depth is also dependent on the lens diameter and the material being cut. Therefore, it is important to control the position of the focus relative to the material surface to be cut.
Because of the great influence of laser power density on cutting speed, the choice of lens focal length is an important problem. The size of the spot after focusing the laser beam is proportional to the focal length of the lens. The size of the spot after the beam is focused by the short focal length lens is very small, and the power density at the focal point is very high, which is beneficial to material cutting. But its disadvantage is that the focal depth is very short, the adjustment allowance is small, generally more suitable for high-speed cutting thin material. Because the long focal length lens has a wide focal depth, as long as it has enough power density, it is more suitable for cutting thick workpiece.
The position of the focus relative to the workpiece surface is very important to ensure the cutting quality after determining the lens of focal length. Because the power density is highest at the focal point, in most cases, the focal point is just on the surface of the workpiece, or just below the surface. In the whole cutting process, keeping the relative position of the focus and the workpiece constant is an important condition to obtain stable cutting quality. Sometimes, the lens is heated due to improper cooling, which causes the change of focal length, which requires timely adjustment of the focal position.
When the focus is in the best position, the slit is the smallest, the efficiency is the highest, and the best cutting speed can get the best cutting result. In most applications, the focus of the beam is adjusted just below the nozzle. The distance between nozzle and workpiece surface is generally about 1.5mm.
In the process of laser application, problems such as focusing are often encountered. There are three simple ways to determine the position of the focus:
(1) Printing method: make the cutting head move from top to bottom, carry out laser beam printing on the plastic plate, and the smallest print diameter is the focus.
(2) inclined plate method: with a vertical axis into an Angle inclined to put the plastic plate to pull it horizontally, looking for the smallest laser beam as the focus.
(3) blue spark method: remove the nozzle, blow air, the pulse laser hit the stainless steel plate, so that the cutting head from up to down, until the largest blue spark as the focus.