Views: 290 Author: laura Publish Time: 2022-07-18 Origin: Site
An ideal metal fabrication equipment can bring you more than high profits. In recent years, fiber laser cutter has become increasingly popular in metal processing. We know that fiber laser is kind of ideal lasers that achieve all the requirements of small size, high efficiency, high reliability, high beam quality and high output by amplifying light of specific wavelengths in the fiber. What exactly is that? Let's take a look together.
What is fiber laser?
Optical fiber is usually a glass solid fiber drawn from SiO2 as the matrix material, which is widely used in optical fiber communications. The principle of light guiding is the mechanism of total internal reflection of light. That is, when the light is incident from the light-dense medium with a large refractive index to an optically sparser medium with a small refractive index at an angle greater than the critical angle, total reflection will occur, and the incident light will all be reflected to the light-dense medium with a large refractive index, and the refractive index is small.
Fiber can be divided into single-mode fiber and multi-mode fiber. Single-mode fiber has a small core diameter and can transmit only one mode of light, with small inter-mode dispersion. The core diameter of multi-mode fiber is thick, which can transmit multiple modes of light, but the dispersion between modes is relatively large.
The transmission mode of the fiber laser is to use the fiber to conduct laser beam. Generally speaking, the principle is to wrap a layer of YAG crystal in the inner and outer circles of the optical fiber, so that the light source can illuminate the YAG crystal from the optical fiber to generate laser, and at the same time, repeated refraction conduction is carried out in the optical fiber.
The working principle of fiber laser is mainly based on its special structure. The laser is composed of three parts: working material, pump source and resonator. And the specific functions are as follows:
1. The gain fiber is the gain medium that generates photons.
2. The pumping light acts as an external energy to make the gain medium achieve population inversion, that is, the pump source.
3. The optical resonator is composed of two mirrors, and the role is to make the photon feedback and amplification in the working medium.
What the differences among fiber laser, CO2 laser and YAG solid-state laser?
Are you still not sure which kind of laser cutter is right for you? Do you think that the fiber laser cutting machine is too expensive, but the effects of CO2 laser or YAG laser cutting always fail to meet your expectations? Hopefully the below will help you understand better.
Fiber laser belongs to solid-state laser. It generates a laser beam with a seed laser, which is then amplified in a specially designed glass fiber to provide energy through a pump diode. The fiber laser has a wavelength of 1.064 microns, which can produce very small focal spot diameter. The intensity is more than 100 times that of a CO2 laser device with the same average power. And also, fiber laser has an exceptionally long service life of at least 25,000 laser processing man-hours.
CO2 laser is a gas laser based on a carbon dioxide gas mixture excited by electrical discharge. It has a wavelength of 10.6 microns and is mainly suitable for processing non-metallic materials and most plastics. CO2 laser has relatively high efficiency and have excellent beam quality. Therefore, it is one of the most widely used laser devices.
YAG laser is also a kind of solid-state laser, named after the doped element neodymium and carrier crystal, which has a wavelength of 1.064 microns, the same wavelength as fiber laser, making it suitable for marking metals and plastics. Unlike fiber laser, this type of laser devices include relatively expensive pump diodes, which are consumables. It must be replaced after about 8,000 to 15,000 machining hours. Compared to fiber laser, YAG laser has a shorter lifetime and is more suitable for metal and coated metal.
Here are some specific parameter comparisons.
What can fiber laser cutting machine?
As mentioned above, the wavelength of CO2 laser and solid-state laser such as YAG or fiber laser determines that the former is more easily absorbed by non-metals, and can cut non-metallic materials such as wood, acrylic, PP, organic glass, etc. with high quality, while the latter is not easily absorbed by non-metals. Moreover, the wavelengths of the two differ by an order of magnitude, which greatly increases the flexibility of fiber laser processing.
But both CO2 and YAG laser are helpless when encountering highly reflective materials such as copper and pure aluminum. It always fail to cut a highly reflective material using CO2 laser anyway, because the power or beam transmitted to the material will be reflected back. The YAG laser is only used for thin plate cutting below 8mm.
CNC fiber laser cutting machine does not have these limitations.
However, Senfeng does not recommend using fiber laser for long-term cutting of highly reflective materials. The so-called high reflection has little to do with the smoothness of the cutting surface of the sheet, mainly because the wavelength of the laser is not within the ideal absorption range of these materials. Most of the energy is reflected back, which is easy to damage the protective lens in front of the laser head. If it is used for a long time, the cutting effect is not as expected, but also increase the consumption of consumables.
In the same way, fiber laser cutting equipment cannot process non-metals such as fabrics, leather, and stones, and the advantages of non-metal cutting are not obvious.
What are the advantages of fiber laser?
Compared with previous solid-state laser, fiber laser has tons of advantages.
1. Great beam quality
The waveguide structure of the fiber determines that the fiber laser is easy to obtain single transverse mode output, and is less affected by external factors, which can achieve high-brightness laser output.
2. High efficiency
Its electro-optical conversion efficiency reaches 30%, which is several times higher than that of traditional laser cutting machine, while the comprehensive operating cost is only 15% of traditional laser cutter.
3. Excellent heat dissipation
Fiber laser uses slender rare-earth element fiber as laser gain media, which has a very large surface area to volume ratio. It is about 1000 times that of traditional solid-state laser, and has a natural advantage in heat dissipation. In the case of medium and low power, no special cooling of the optical fiber is required, and in the case of high power, water cooling is used to effectively avoid the reduction of beam quality and efficiency caused by thermal effects commonly seen in solid-state laser.
4. Compact structure and high reliability
The pump source is also a semiconductor laser that is small in size and easy to be modularized. Combined with Fiber Bragg Grating (FBG) and other fiber-optic devices, as long as these devices are welded to each other, all-fiber lasers can be realized. High disturbance immunity and high stability can save your maintenance time and expense.
What are the disadvantages of fiber laser?
Every coin has two sides. Here are a few disadvantages of fiber laser.
1. The price is higher.
Fiber laser production and development costs and spare parts costs are much higher than other lasers.
2. Due to the small core of the fiber, its single pulse energy is very small compared to solid-state lasers.
3. Limitations on cutting sheet materials.
Usually only limited to the field of metal processing, and it is unlikely to make a difference in non-metal processing, such as plastic, paper or cloth.
What is the maximum thickness that the fiber laser cutting machine can cut?
Different power cutting devices have different production effects. Take a look at the table below to learn more about each fiber laser cutter.
In the process of practical application, the cutting ability of fiber laser cutting equipment is also related to the quality of the cutting machine, laser type, cutting environment, cutting speed and other factors. The use of auxiliary gas can also improve a certain cutting ability, so there is no absolute standard to judge its cutting thickness. For example, the cutting of carbon steel mainly relies on oxygen combustion, and the cutting of stainless steel mainly depends on power. Generally, a 1000w fiber laser cutting machine can cut carbon steel plates with a thickness of about 10mm, and stainless steel plates are slightly more difficult to cut. To increase the cutting thickness, it is at the expense of the edge effect and speed.
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