Research progress of Professor Yongqiang Yang's team from South China University of Technology in the field of new generation SLM technology

3D printing technology reference Zeng wrote and pointed out that the new generation of SLM technology has shown a differentiated competitive trend.
These differentiations revolve around the "pain points" that have been concerned about molding efficiency, manufacturing costs, post-processing, and quality assurance.
A series of new technologies have been born, which not only enriches product types, but also brings new vitality to this technology that has been developed for more than 20 years
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In this issue, 3D printing technology reference introduces the research progress of Professor Yang Yongqiang's team from South China University of Technology in the field of new generation SLM technology
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?? Dual-wavelength laser powder bed metal 3D printer? Combine 1070nm infrared fiber laser with 450nm blue semiconductor laser to realize infrared/blue composite, which can print conventional materials such as titanium alloy, aluminum alloy and stainless steel, and can also print right Infrared light has high reaction of gold, silver, pure copper and other materials, in the actual processing process, only need to switch the laser according to the material
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This is a project being undertaken by the team of Professor Yongqiang Yang from South China University of Technology
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? "? This type of metal 3D printer has not yet seen a specific case in the market, but it has high application value, especially for processing service-oriented platforms and universities in the field of scientific research
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At present, Professor Yongqiang Yang The team has achieved relatively good results in the composite printing research of two different lasers
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? The metal 3D printer represented by powder bed melting can easily reach millions, while the infrared fiber laser equipped with traditional models is printing pure copper, etc.
There are disadvantages in materials
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Although there are currently commercially available printers equipped with green lasers, it will undoubtedly increase the purchase cost for applications with multiple needs
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The development of dual-wavelength printers is the performance of the new generation of SLM technology differentiation.
It has practical application value
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? "? 3D printing technology reference inquired about the patents of this research of South China University of Technology.
Relevant materials pointed out that the application of lasers with wavelengths of 450-560nm improved the use of high-reflective metal powders such as magnesium, aluminum, and copper alloys.
The absorptivity in laser selective melting technology improves the processing quality and processing efficiency of high-reflectivity metal materials
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A blue-green laser micro-melting molding device for high-reflective materials.
The final focus spot diameter is less than 15μm.
The 5-10μm fine powder is used to achieve a dimensional accuracy of 5μm, a characteristic size of less than 10μm, and a surface roughness Ra of less than 2μm.
More than 99% of the blue/green laser selected area is slightly melted
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? 8Laser large-format metal 3D printer? It is more effective at present to increase the printing size and increase the efficiency while ensuring the accuracy.
Increase the number of galvanometers and lasers
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Using simple galvanometer splicing to increase the print size can increase the print size to more than 600mm.
However, the size of full-format printing realized by 2 galvanometers or 4 galvanometers will be limited to 300-400mm; 4 galvanometers splicing and printing efficiency are improved Limited, less than four times; 9 galvanometer splicing has too many overlapping surfaces
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? Professor Yang Yongqiang's team and Han's Laser have undertaken the key research and development plan of Guangdong Province, and are developing a large-format 3D printer with 8 lasers and 4 dual galvanometer groups for dynamic focusing
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According to Professor Yang Yongqiang's introduction, in this scheme, two lasers are responsible for the same format, and 8 lasers are divided into four zones to achieve large-format printing
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? "There are multiple combinations of laser and galvanometer arrangements.
How to combine them more effectively? The most important thing is to solve the problems of coordinated control and optical adjustment of multiple galvanometers
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? One of the biggest problems faced by multi-laser large-format printers It is the problem of air flow and wind field.
Smoke and splashes in the printing process are unavoidable.
They will be more serious in the case of multiple lasers.
The structure design of the air flow field, the position in the molding cavity, and the size of the air flow in and out will all affect the material.
This is a universal problem of this technology.
Professor Yang Yongqiang’s team has dedicated doctoral students working in this area
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? "? The largest commercial printer developed by the team is four laser four The Dimetal-650 of the galvanometer, with a molding size of 620*620*1100mm, will be exhibited at TCT 3D Printing Exhibition
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? Multi-material powder spreading metal 3D printer? The team of Professor Yang Yongqiang of South China University of Technology developed a multi-material spreading metal 3D printer based on SLM technology.
The powder feed method is used to add powder during the molding process without interruption of printing.
, Can achieve 1-4 kinds of material gradient forming, selective area forming, support single material and multiple material conversion
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Through the control system, the data of different powder dosages can also be monitored in real time
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? "? Composition gradient alloys have important application value in the aerospace and nuclear fields.
Different parts of components may choose different materials according to
different working conditions.
These different working conditions may require a specific main function, such as a location Corrosion resistance is needed and another location needs creep resistance, which requires the connection of two or more different alloys
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At the same time, composition gradient materials can significantly reduce costs in some applications.
AVIC Shenyang Aircraft Design and Research Institute adopts additive manufacturing Achieved 300M and A-100 steel gradient composite design molding, which reduces the manufacturing cost of aircraft landing gear by 45%
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? "? The use of laser powder bed melting and direct energy deposition provides an attractive way for the manufacture of composition gradient alloys.
Way, their layered powder feeding mechanism can introduce the gradient of chemical composition in multiple spatial dimensions
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