This article focuses on laser processing technology, a detailed introduction to its characteristics, the application of machinery manufacturing in engineering and development trends.
I believe that after reading this article you can have a more detailed understanding of laser processing.
As an important branch of the machinery manufacturing industry, engineering machinery has the advantages of multiple categories, complex functions and high structural strength.
Although it has rarely been a testing ground for a variety of new manufacturing technologies, due to the innovative spirit of scientific and technological personnel and the courage to overcome difficulties, new technologies will eventually spread to the field of engineering machinery manufacturing, such as welding robots, automation, intelligent logistics and so on.
Naturally, laser processing technology, as a green, environmentally friendly, efficient and non-contact object processing technology, is also favored by the industry.
II. The characteristics of laser processing
Laser processing, which originated in Germany in the 1960s, is mainly to use the high-energy particles produced by the laser to melt and vaporize the surface of the workpiece, and use this principle to carry out various derivative processing technologies.
Due to the high stability and anti-interference of the laser beam, and it has fewer restrictions on the workpiece (such as processing shape, size, environment), so it is possible to process most metallic and non-metallic materials with high quality and precision.
Laser processing technology has always been a representative of “high precision and special” technology.
In general, the characteristics and advantages of laser processing can be summarized as “high, fast, good, economical and wide”, as follows:
Laser processing has high precision, high processing efficiency, high material utilization and high economic efficiency.
For example, a laser cutting machine with a price of $50,000, the company can recover the cost of the equipment and generate profits in one and a half years under normal processing.
The processing speed is fast, as the energy medium of the laser is the light source, its processing speed is very fast, up to 100m/min.
At present, the most advanced 3G laser cutting machine is more than 1.5 times faster than the mainstream processing equipment.
Laser processing is resistant to interference and is not easily affected by environmental factors, so the quality of the parts produced by laser processing is very good and the accuracy can be at the same level (micron level) as that of ordinary machine tool finish machining.
Laser-processed products are more material-efficient and less material intensive.
According to incomplete statistics, laser processing can save 10% to 30% of materials compared to other processing technologies.
In addition, laser processing is a non-contact process, so the equipment requires fewer consumables, greatly reducing production costs.
Laser processing can be applied to a wide range of materials, not only to metallic materials, but also to non-metallic materials.
In addition, laser processing can process a wide range of shapes, such as straight lines, curves, and shaped patterns, making it truly barrier-free.
III. The application of laser processing technology in engineering machinery manufacturing
In recent years, with the breakthrough in laser processing technology and equipment, it is more used in the manufacturing of construction machinery products in various processes.
The following is an introduction to the current mainstream technology for construction machinery applications:
3.1 Laser processing technology in the field of sheet metal cutting applications
Laser cutting is a cutting method that uses a laser beam output from a laser oscillator to focus a laser beam through a focal mirror, and the high-density energy generated is irradiated on the material, causing it to melt and evaporate.
Compared to the thermal cutting methods (flame, plasma, etc.) commonly used in production, the large energy per unit area makes it possible to cut high-precision products with smaller slits.
For example, a company’s blanking center has more than 100 equipment in six categories: fine plasma cutting, fiber laser cutting, flat bevel cutting, pipe intersecting line cutting, integrated drilling and cutting machines, and section steel cutting, which is for construction machinery manufacturers Carter, Komatsu, John Deere, as well as domestic construction machinery and the right subsidiary products blanking, as well as serving the needs of local supporting enterprises.
It includes three two-dimensional laser cutting machines (see Figure 1) and two three-dimensional laser cutting machines (see Figure 2).
Laser blanking products involve almost all types of construction machinery, such as hoods, fuel tanks, cabs and other parts and components, with a thickness of 1 to 25mm plate or profile.
The cutting materials range from general Q235A to 1000MPa high strength plate and the annual blanking capacity reaches 20,000t.
Figure 1 Two-dimensional laser cutting machine
Figure 2 3D laser cutting machine
At present, there are two types of laser cutting machines used in mainstream technology products in the engineering machinery sheet processing industry: CO2 laser cutting machines and fiber laser cutting machines.
CO2 laser cutting machine is an early product, the technology is not as advanced as fiber laser, and the wavelength is about 1/10 of that of fiber.
Propagation is generally carried out in an optical path isolated from the outside air.
The fiber laser propagates in the fiber, with better passability and higher energy beam, so that the thermal influence is smaller and the cutting line is narrower, which is beneficial to improve the blanking efficiency, material utilization, and thermal deformation of the plate blanking.
In addition to conventional laser cutting and blanking, laser cutting technology has obvious advantages in circular hole cutting, reserved process gaps, and process model production.
It can be applied to “cutting instead of drilling” for process equipment holes, saving the time of the drilling process, improving production efficiency, and saving the production cost of drilling template.
3.2 Application of laser processing technology in welding
Most traditional construction machinery welding techniques use gas shielded welding, submerged arc welding or argon arc welding.
The welded products tend to have quality defects such as excessive splatter and distortion.
In addition to the welding arc light, dust will also endanger the physical and mental health of the operator.
With the development of technology, industrial products manufacturers are also on how to improve welding quality, efficiency and reduce manual work to do a lot of work, and gradually introduced the concept of automotive industry body-in-white robot welding, assembly line and flexible manufacturing to the construction machinery welding process.
In the early days, due to insufficient laser power and limited laser welding technology, it could not be used in engineering machinery products that were mostly medium-thick or ultra-thick plates.
But in recent years, Shanghai Jiao Tong University, Harbin Institute of Technology and other well-known universities have conducted a lot of research and experiments for medium-thick plate laser welding technology, which also has formed a high-power laser deep fusion welding, arc composite welding, ultra-narrow gap multi-layer fillet welding and vacuum negative pressure laser welding and other welding methods.
The laser arc hybrid welding technology has been successfully applied to the boom of construction machinery cranes, which combines two heat sources with completely different energy transmission mechanisms and physical characteristics to act on a unified welding position.
It can also take advantage of the two heat sources so that the weld depth increases, gap bridging ability enhances and the welding efficiency improves, to play 1 +1>2 effects.
For example, the material of the reach arm of the truck crane is high-strength steel with yield strength of 960MPa, which is laser-twin wire MAG composite welding (see Figure 3).
Compared with traditional welding, it has strong welding adaptability and can be used for high reflection welding, difficult welding and dissimilar materials welding;
It improves the stability of the welding process and weld formation and can eliminate welding defects to improve the quality of the weld seam, which has a 100% inspection pass.
The efficiency is increased by 300%.
Compared with single heat source welding, hybrid welding can effectively increase the penetration depth by 50%, increase the welding speed and ensure a smaller heat input;
It has higher filling efficiency and saves more than 30% of the unit wire consumption.
Fig. 3 Example of laser-composite MAG welding application
3.3 Applications of laser processing technology in remanufacturing
In recent years, the construction machinery remanufacturing business has developed relatively quickly.
On the one hand, energy-saving and consumption reduction belong to the category of green manufacturing, which the country strongly advocates;
On the other hand, the performance of the remanufactured product is essentially comparable to the new product, at about 2/3 the price of the new product.
Users are gradually accepting the recognition.
Because only 40% to 60% of the manufacturing costs, companies are also willing to do.
Parts remanufacturing mainly involves replacing wear parts, seals and repairing wear and tear in mechanisms, where the most important technology used is high-efficiency laser welding, also known as laser cladding.
The main principle is to use a high-power, high-density laser beam to form a micro-melting layer on the surface of the substrate, and to preset or simultaneously add a specific composition of direct-melting alloy powder, so as to achieve the purpose of uniformly repairing worn parts.
It also belongs to a kind of material augmentation manufacturing technology.
At the same time, it has high flexibility, optional surfacing area, optional materials and even performance optional, which provides high-quality and feasible manufacturing solutions for realizing differentiated customization of products.
For example, the crawler spring barrel for the chassis of a high-power bulldozer is worn out during use, and the remanufacturing adopts laser cladding additive processing for the worn area (see Figure 4).
Tested from multiple dimensions of wear resistance, the surface hardness is qualified, the layer hardness gradient in the cladding layer is reasonable, and the metallographic structure is good, which can increase the life of the spring barrel of the high-power bulldozer by 300%.
It is now not only used for remanufacturing but also replaces the original chrome plating and pre-induction heat treatment process on new products, greatly enhancing the competitiveness of the product in the industry.
Fig. 4 Laser augmentation of spring barrel for high power dozers
3.4 Application of laser processing technology in the field of quality management
The ISO 9000 quality management system clearly requires process monitoring of parts and components, and the quality must be traceable.
In order to effectively trace the quality and use of parts and components, construction machinery manufacturers also require permanent identification of self-made parts and accessories, which mainly includes basic information such as product name, material number, drawing number, manufacturer, production date and two-dimensional code.
The traditional marking technology mainly uses the continuous mechanical movement of the cylinder to impact the object, leaving a movement track on the surface of the sign.
This method has disadvantages such as large noise, blurred writing, and deformation of the sign.
The laser marking technology belongs to the contactless processing, which uses the beam emitted by the laser to melt the material on the surface of the workpiece instantly by controlling the path of the laser on the surface of the material, thus forming a method of graphic marking, as shown in Figure 5.
Compared with traditional methods, it has the following advantages:
①The speed is fast, which is more than double the traditional speed.
②High quality font, clear handwriting, and a lot of complex patterns, symbols, letters can also be printed out, which is incomparable to traditional marking.
③Non-contact processing, environmental protection and pollution-free, combined with CNC software system, automatic marking can be realized.
a) Pneumatic marking
b) Laser marking
Fig.5 Comparison example of signage coding applications
As can be seen from the above examples, laser processing technology has been continuously applied to various process steps in engineering machinery manufacturing, and laser cleaning technology is attracting attention from the aerospace, automotive, construction machinery and other fields.
The process can be used to remove paint, clean mold or remove the oxidation layer and coating before welding.
The speed is faster and less waste is produced, which is applied less in the current construction machinery industry.
For the above-mentioned laser processing technology, most construction machinery enterprises have incorporated it into their own corporate process standards to enhance the quality and efficiency of products.
With the accelerated localization of laser processing technology, some small and medium-sized enterprises also try to buy laser equipment for laser processing to reduce labor costs and improve product quality.
But compared to the mature standardized applications abroad, domestic processors still have a long way to go.
IV. Development trend of laser processing technology
The laser processing technology is a set of mechanical, electrical, numerical control, optical and hydraulic and other fields combined with a complex system.
The technical threshold for enterprises to enter this field is relatively high, so the developed countries like the United Kingdom, Germany, the United States etc. have been leading the direction of the development of the laser processing industry.
Although Chinese entry into this field is relatively late, with the continuous implementation of the national strategy “Made in China 2025”, Chinese laser equipment manufacturers and scientific research institutions have worked hard, and emerging stars such as Han’s Laser.
The gap between technology and foreign laser equipment is constantly narrowing.
In addition, the development of laser processing technology is also a long and arduous process, requiring the efforts of all aspects of society.
I believe that the future of laser processing technology will be to the following aspects of development.
(1) Laser miniaturization
As a core component of laser processing technology, laser size will determine the size of the entire machine.
Due to the limitations of microelectronics and optical technology in the early stage, lasers are relatively large in size and occupy a large area.
With the continuous progress and development of new laser technology (such as fiber optic technology, UV technology, etc.), a number of lasers with high conversion efficiency, good working stability, good beam quality, small size of the laser was developed, thus providing a good basis for the miniaturization of laser equipment.
(2) Multi-functional processing
In order to meet the market demand, laser equipment manufacturers will no longer pursue a single laser processing function, but to develop integrated cutting, welding, heat treatment and spraying in two or more multi-functional equipment in one, to maximize the value of equipment for customers.
(3) Equipment Intelligence
With the rise of Internet technology, equipment intelligence will be another major trend in laser processing technology.
The smart factory will upload all kinds of production plans and material processing data to the enterprise cloud, and engineers will be able to control the operation status of the equipment through remote terminal remote control in the office to realize the digitalization, automation and informatization of the product manufacturing process.
With the implementation of the “Made in China 2025” plan, laser processing technology, with its incomparable advantages, has become an important tool to promote the transformation and upgrading of the construction machinery industry.
After the massive introduction of information technology such as Internet+ and 5G, laser processing and manufacturing have also begun to transform to intelligent manufacturing.
Under the background that the country vigorously encourages enterprises to insist on technological innovation, domestic laser manufacturers will continue to increase R&D investment to provide the market with laser equipment with higher cost performance, which drives the innovation of emerging fields and traditional manufacturing processes, and provides technical support for the wider application of laser processing technology in the construction machinery manufacturing industry in the future.
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