For industrial processing, which is better, fiber laser or CO2 laser?
What are the advantages and disadvantages of these two lasers?
Can fiber lasers replace CO2 lasers?
It may not be easy to clarify this seemingly simple question.
We try to provide users with complete information and balanced opinions from various aspects and angles, in order to receive the effect of doubt resolution.
The wavelength of the laser generated by the fiber laser (hereinafter referred to as fiber laser) is 1.06 μ m. The laser generated by CO2 laser (hereinafter referred to as CO2 laser) has a wavelength of 10.6 μ m. All are infrared light, which can be absorbed by materials and applied to industrial material processing.
Cutting is the most widely used laser industrial processing technology. For convenience, the discussion in this paper is based on laser cutting, unless otherwise specified.
Advantages and disadvantages of the two lasers
As a user, you must first understand the dead spots of fiber laser and CO2 laser. The so-called dead hole is the blind area of cutting processing. After avoiding the dead spot (blind spot), we will compete for the short and choose the one that suits the needs.
The Dead Hole of Fiber Laser
Optical fiber laser cannot cut nonmetals, including wood, plastic, leather, cotton and linen fabrics. If the work-piece material to be processed is just nonmetal, then the fiber laser can only be rejected, rather than the CO2 laser.
Automotive interior parts are mostly non-metallic materials. The high-precision robot+CO2 laser processing system is used to cut their space surfaces. Such a processing system needs to solve the problem of laser beam transmission between robot joints.
Optical fiber laser can not cut materials with coating on the surface, such as ordinary coated stainless steel, special steel plate with antirust coating, etc. Some users did not pay enough attention to this, but chose the fiber laser, and had to cut the ordinary coated stainless steel. If the special coating for fiber laser is used, the cost will increase.
Deadhole of CO2 laser
CO2 laser cannot cut copper materials, including brass and red copper. If it is necessary to cut copper, only fiber laser is qualified.
For CO2 laser, copper is a highly reflective material, and the laser is almost completely reflected but not absorbed; Reflected light returns to the laser, causing harm.
The reflectivity of CO2 laser to aluminum alloy is also high. The installation of back reflection isolator can effectively protect the CO2 laser, so that aluminum alloy can be safely cut.
We also let the two lasers compete for advantages in terms of use cost, cutting speed, perforation efficiency, section quality, etc.
Use cost
Here, in order to compare the cost difference between the two lasers, only the cost of electricity, consumables and dielectric gas is calculated. The cost of these three parts is different; The cost of labor, depreciation, site, cutting gas, etc. for the two lasers is the same, so it is not calculated.
Both lasers require huge amounts of power. The electro-optical conversion efficiency of fiber laser is about 30%, and that of CO2 laser is about 10%. As for 3000W laser, the power consumption of fiber laser is about 10kW, while that of CO2 laser is about 30kW. The cost is 7 yuan/hour and 21 yuan/hour respectively when the electricity price is 1 yuan/hour and the load rate is 70%. WeChat of metal processing has good content and deserves attention.
In addition, due to different efficiency, the heat generated by the two lasers is different, and the specifications (cooling capacity) of the water cooler required are also different. The power consumption of the water cooler required by the fiber laser is 13kW, and the power consumption of the water cooler required by the CO2 laser is 18kW. The cost is 9 yuan/hour and 12.8 yuan/hour respectively when the electricity price is 1 yuan/hour and the load rate is 70%.
In the daily use process, the cutting machine using fiber laser (hereinafter referred to as fiber cutting machine) needs to consume materials such as focusing mirror, ceramic body, nozzle, protective mirror, etc., and the cost is about 3 yuan/hour.
In addition, according to the statistics over the past four years, the laser module and beam expander have their own service life, resulting in costs of about 4 yuan/hour and 1 yuan/hour respectively (especially, the smallest unit to be replaced for ROFIN fiber laser is the semiconductor module, with a cost of about 1 yuan/hour).
The cutting machine using CO2 laser (hereinafter referred to as CO2 cutting machine) needs to consume materials such as focusing mirror, ceramic body, nozzle, reflector, etc., and the cost is about 2.5 yuan/hour.
Fiber laser does not need medium gas; CO2 laser requires medium gas to produce laser, and the cost is about 1 yuan/hour.
In addition, the CO2 laser carries out routine spot inspection every 3000 hours and in-depth spot inspection every 6000 hours, resulting in a cost of about 2 yuan/hour.
Typical fiber laser application system
To sum up, the use cost of fiber laser is about 24 yuan/hour, while that of CO2 laser is about 38.3 yuan/hour, with a difference of 14.3 yuan/hour. If you use 10 hours a day, the daily cost difference is 143 yuan.
The market claims about the difference between the use costs of the two lasers are exaggerated.
Incidentally, the transmission medium of optical fiber laser is optical fiber, and the beam is enclosed in the optical fiber, "curvilinear propagation", which is not affected by the external environment. The CO2 laser transmission medium is air, which travels in a straight line. The transmission direction is changed by mirrors, which are vulnerable to external environment. These mirrors may need to be maintained, thus slightly increasing the use cost.
Cutting speed
Cutting speed, perforation efficiency, section quality and other aspects constitute the laser cutting efficiency, which is a comprehensive index to evaluate the laser (machine). WeChat of metal processing has good content and deserves attention.
Fiber laser has advantages in cutting thin plates, especially when the thickness is less than 3mm. Compared with CO2 laser, the maximum cutting speed ratio can reach 4:1; 6mm is the critical thickness for the exchange of advantages between the two lasers. When cutting plates with thickness>6mm, fiber laser has no advantage; With the increase of thickness, CO2 gradually shows its advantages, but it is not significant.
In general, fiber laser has advantages in cutting speed.
Perforation efficiency
Before the laser beam starts cutting the workpiece, it is necessary to penetrate the workpiece. The perforation time of fiber laser is obviously longer than that of CO2.
Take 3kW fiber laser and CO2 laser as examples. For 8mm thick carbon steel, the latter is less than the former for 1 second; 10mm, the latter is less than 2 seconds; With the increase of the thickness, CO2 laser has more and more advantages in perforation.
If the perforation time difference is 3 seconds for 2000 times per day, the perforation time difference is 6000 seconds per day, which is about 1.7 hours.
The CO2 laser can reduce the machine service time by 1.7 hours per day due to its high perforation efficiency. Even if more conservative data are used, including labor (30 yuan/hour), equipment depreciation (25 yuan/hour) and site (2 yuan/hour) costs, the costs saved are (CO2 laser):
one point seven × (30+25+2+38.3)=162 yuan
Section quality
Section quality usually refers to roughness (finish) and perpendicularity.
When cutting steel plates with thickness less than 3mm, the section quality (roughness and perpendicularity) of optical fiber laser cutting is slightly worse than that of CO2. With the increase of thickness, the difference of section quality becomes more and more obvious.
For stainless steel with thickness ≥ 3mm, the section cut by optical fiber laser is frosted, while CO2 is bright.
For carbon steel with a thickness of 16mm, the perpendicularity of the optical fiber laser cutting section is far worse than that of CO2, the former is 0.4~0.5mm, and the latter is 0.1mm.
In addition, carbon steel plate has a high absorption rate of optical fiber laser energy, which is a disadvantage when cutting small holes (aperture ≤ plate thickness), and the cutting quality is poor.
By the way, the accuracy of laser cutting is not related to which laser is used, but to the consistency of machine positioning accuracy, repetitive positioning accuracy and slit width. The slit of fiber laser cutting is narrow, while that of CO2 cutting is slightly wide. However, the width of the slit does not affect the accuracy of the part, because the slit compensation function can offset the slit width.