With the continuous development of heavy industry, laser cutting technology has developed from thin plate cutting to thick plate large-size cutting, and laser cutting has gradually entered the era of high-power laser cutting machines. The industrial manufacturing of the new era has put forward new requirements for the cutting accuracy, speed, thickness, etc. of metal plates, and the power that laser cutting machines can achieve is getting higher and higher. From the perspective of industrial development, the application of high-power laser cutting machines in more and more industries is a major trend in the development of the industry.
1 Introduction
In the field of metal sheet processing, the advantages of laser cutting machines are very prominent. Due to its high precision, fast speed, and good quality, it has gradually replaced traditional processing technology and become the core equipment for metal sheet cutting. From the rise of laser cutting machines, to the replacement of YAG, CO2 and other machines by fiber laser cutting machines, to the continuous introduction of high-power laser cutting machines, high-power equipment has become a general trend for cutting thick plates and cutting efficiency.
In recent years, high-power laser cutting machines have become a hot topic in the field of laser cutting, and many companies have continuously launched fiber laser cutting equipment with a power of more than 10,000 watts. For the sheet metal processing industry, the birth of high-power cutting equipment has greatly improved the thickness and efficiency of sheet metal cutting. The emergence of such high-power cutting machines has continuously broken the limit of material cutting thickness. The resulting reduction in the price of processing thick plates has formed a good cycle and promoted the further expansion of the application field of laser cutting.
2 Introduction to high-power laser cutting machines
(1) Introduction to high-power cutting machines Laser cutting machines can be divided into low-power, medium-power and high-power according to power. For stainless steel and carbon steel of normal thickness, low-power laser cutting machines can perform good cutting. For cutting thick plates and cutting efficiency, high-power laser cutting machines can achieve good results. Therefore, laser cutting machines with laser power above 10,000 watts are collectively referred to as high-power laser cutting machines (see Figure 1).
Figure 1
(2) Specifications of fiber laser power The power specifications of the fiber laser selected on the high-power cutting machine are different according to the thickness of the laser cutting metal sheet. From the current development trend, in the metal processing market, large, medium and small enterprises are gradually upgrading to a variety of specifications, see Table 1.
Table 1 Specifications of high-power fiber lasers
| Laser Power/KW | 10 | 12 | 20 | 25 | 30 | 35 |
| Remark | Conventional | Conventional | Conventional | Scarce | Scarce | Scarce |
(3) Specifications of the gas used When a high-power laser cutting machine is working, in order to ensure the cutting accuracy, cutting speed, cutting section effect and many other advantages, the purity of the oxygen used is required to be high, generally requiring a purity of 99.99%.
3 Features of high-power laser cutting machines
3.1 Technological breakthroughs
(1) High-speed cutting machine with high dynamic performance The machine equipped with a 10,000-watt fiber laser adopts a new triangular structure beam with the following features: ① The weight is reduced by 30%, and the dynamic performance is significantly improved. ② The maximum moving speed can reach 200m/min, and the dynamic response characteristics of the acceleration are 4g. ③ The base is increased in weight by about 20%, and the fixing method of the machine is changed to eliminate the impact of high acceleration movement on the machine.
(2) Brand-new software system The software and control system are like the brain and command center of the machine tool. In addition to the benefits brought by hardware upgrades, the differences in the accuracy and efficiency of the machine tool operation mainly come from the differences in software and control systems, and the differences are often very large.
(3) Stable cutting at a speed of up to 100m/min can be achieved ① The response speed of the capacitive sensor is 3 times faster than that of the traditional cutting head.
② The Z-axis speed is increased, the operation is smoother and there is no pause. The efficiency of thin plate cutting is increased by more than 30%, the efficiency of the frog jump function is improved, and the acceleration adaptation function is improved. ③ The functions of fast punching and precision punching as well as the remote diagnosis function are improved, and the intelligent interface is reserved for the realization of the “Industry 4.0” function.
3.2 Cutting head features
The high-power cutting head is the core component to ensure stable cutting under high-power continuous operation. It has the following features: ① The high-power cutting head has a cooling system with better sealing and more adequate cooling, a focus with a wider range of applications, and a lens that is resistant to high temperatures. ② Due to the influence of the high-power thermal lens effect, the beam will drift after a long period of operation. In order to overcome the problem of focus drift, the high-power cutting head adopts a new gas path design structure and replaces the nozzle with a new structure to improve the cutting speed and cutting stability.
3.3 High-power laser cutting capability
(1) The thickness of cutting thick plates is constantly increasing. At present, the thickness of aluminum alloy plates cut by high-power laser cutting machines can reach 40mm, and the thickness of stainless steel plates can reach 130mm. With the continuous upgrading of high-power laser cutting machine technology, the thickness of cutting materials will continue to increase, the price of processing thick plates will gradually decrease, and the application of high-power laser cutting machines in the field of thick plates will be accelerated.
Figure 2
(2) Doubled efficiency of cutting medium and thin plates ① When cutting stainless steel plates with a thickness of 3 to 10 mm, the cutting speed of a 10,000W laser cutting machine is more than twice that of a 6,000W one. ② In the application of cutting carbon steel, a 10,000W laser cutting machine can achieve fast bright surface cutting of 18 to 20 mm/s, which is twice the normal standard cutting speed. ③ Compressed air or nitrogen can be used to cut carbon steel plates within 12 mm, and the cutting efficiency is 6 to 7 times the speed of oxygen cutting carbon steel.
3.4 Bed characteristics
(1) The equipment is equipped with a super-strong load-bearing mechanical structure. High-power cutting machines are equipped with a cast iron bed, which is cast in one piece with a minimum tensile strength of 200 MPa flake graphite cast iron. The carbon content, compressive strength, vibration damping and wear resistance have been greatly improved (see Figure 3).
Figure 3
(2) Characteristics of cast iron bed ① The bed has good lubrication, corrosion resistance and dimensional stability, reducing processing errors caused by bed vibration. ② Reduce equipment loss during use, increase stability coefficient by more than 30%, improve quality accuracy by more than 30%, and increase bed life by more than 70 years.
3.5 Lightning perforation and extreme small hole forming
(1) Lightning perforation The perforation time is short, the heat focusing energy is small, the starting point is stable, and the stability of the follow-up system is maintained, which can ensure the best cutting effect. The advantages of lightning perforation are shown in Table 2.
| Item | Index | Remark |
|---|---|---|
| Piercing Time | Reduced about 90% | Improve processing efficiency |
| Waste hole rate | From about 10% to about 0.3% | Improve workpiece integrity |
| Save gas and electricity | Reduced damage to laser and cutting head | Improve material utilization |
(2) Extreme small hole In the laser cutting industry, it has always been believed that the thickness of the plate is the minimum diameter of the small hole to be cut. High-power laser cutting machines can achieve a minimum hole diameter of 0.15 times the plate thickness, or even smaller, as shown in Figure 4.
Figure 4
4 . Advantages of high-power laser cutting machines
(1) High speed The laser cutting speed has exceeded 20m/min, the two-axis moving speed of the processing cutting machine can reach 250m/min, and the acceleration during operation has reached about 10g.
(2) High precision About 500 small holes of about φ10mm can be cut per minute in a 1mm thick plate. The error between these small holes is very small during the cutting process.
(3) Development towards thick plates The power of high-power laser cutting machines is gradually increasing, and the corresponding thick plate size is also increasing.
(4) Development towards large sizes The processing size range of laser cutting technology is also increasing, and laser cutting technology has begun to develop towards large sizes.
(5) Automatic unmanned operation Automatic unmanned operation of laser cutting technology has the necessity and urgency of development. ① The application of computer network technology has promoted the automatic unmanned operation of laser cutting technology. ② The market demand for the application of this technology is also increasing, prompting laser cutting technology to achieve full automatic unmanned operation.
(6) Intelligence According to the technical requirements of Industry 4.0, keep up with the pace of intelligent manufacturing. Adopting accurate graphic recognition technology, simple operation procedures, and convenient human-machine intelligent interaction, the laser is combined with computer control, CNC technology, optical system, high-precision and automatic positioning device, etc., and automatic nesting, cutting process database, remote fault diagnosis, remote control, etc. are integrated into one to meet the needs of large-scale and complex parts processing.
5 . Conclusion
(1) Development of high-power equipment Laser cutting, as an ideal processing method in cutting processing, represents the development direction of modern metal processing technology. High-power laser cutting machines are currently conducting key technical research and development in the fields of high speed, high precision, large format, three-dimensional cutting and special material cutting, thereby promoting the development of high-power laser cutting technology to meet the growing market demand.
(2) Selection of high-power equipment Some companies need to carefully consider when choosing high-power laser cutting equipment: in addition to cutting speed and accuracy, they should especially check the stability and consistency of full-power continuous cutting, the speed matching ability of the machine tool, the advancedness of the machine tool control and the precision life. They cannot simply compare the price factor like purchasing low-power laser cutting equipment. High power means high investment, and high investment contains high risk. When companies enter this high-return market, they must be aware of its risks.
