As the most advanced and potential technology in the whole 3D printing system, 3D metal printing is an important development direction of advanced manufacturing technology. With the development of science and technology and the demand for popularization and application, direct manufacturing of metal functional parts by rapid prototyping has become the main development direction of rapid prototyping. SLM 3D printing technology is the most advanced and accurate metal laser 3D printing technology in the world.
Selective Laser Melting, SLM) technology was first proposed by Froounholfer Institute in Germany in 1995, and its working principle is similar to SLS. SLM converts the laser energy into heat energy to mold metal powder. The main difference is that the metal powder is not completely melted during the manufacturing process of SLS, while the metal powder is heated to be completely melted and then molded during the manufacturing process of SLM.
The working flow of SLM is as follows: the printer controls the laser to selectively irradiate the laid powder, and the metal powder is heated to be completely melted before forming. Then the piston lowers the height of the workbench by one unit, and a new layer of powder is spread on the formed current layer. The equipment calls in the data of the new layer of the cross-section for laser melting and bonding with the previous layer of the cross-section. This process circulates layer by layer until the whole object is formed. The whole process of SLM is carried out in a processing chamber protected by inert gas to avoid metal oxidation at high temperatures.
1. The density of metal parts formed by SLM is high, which can reach more than 90%;
2. The mechanical properties such as tensile strength are superior to those of castings, even reaching the level of forgings. Vickers hardness can be higher than that of forgings;
3. Because it is completely melted in the printing process, the dimensional accuracy is high;
4. Compared with traditional material reduction manufacturing, it can save a lot of materials.