3D printing titanium alloy process
Compared with the traditional process, the advantage of using 3D printing technology to manufacture personalized surgical implants is mainly reflected in: 3D printing free-form features can quickly and accurately customize the internal implant, can overcome the traditional shape of the universal implant Incompatibility with the human body and its mechanical properties are not up to the standard; in the manufacture of complex structures and difficult-to-manufacture products, the custom-built microstructure, especially the porous structure, not only can meet specific physical and chemical properties, but also enhance the biological organization. compatibility. This series of advantages can effectively overcome the ubiquitous stress shielding and low biological activity of implants. At present, 3D printing titanium alloy commonly used and most widely used is SLM technology and EBM technology.
Selective Laser Melting (SLM) uses a laser as a heat source to selectively irradiate pre-powdered powder materials for rapid melt forming. Its working principle is mainly in the inert gas protection environment, the instrument and equipment according to the system design mode generated by the fill scan path to control the laser beam to select the region melting layer of powder. Then the platform is moved down, powdered and sintered again, and circulated back and forth until it is integrally formed. The inert gas protection prevents the metal from reacting with other gases at high temperatures. SLM technology has a wide range of molding materials, material saving and recovery, no need to design and prepare a complex supporting system. This series of advantages makes the application of SLM technology more and more widely. However, SLM also has some drawbacks: Because of the limited laser power and scanning galvanometer deflection angle, the size range of parts made by SLM will be limited; high-power lasers and high-quality optical equipment are expensive to manufacture, which to a certain extent Increased economic burden; due to the use of powder materials in SLM technology, the surface quality of molded parts may be problematic, which requires secondary processing of the products for subsequent work; balling and warping may also occur during processing. The flaws require further rigorous optimization of the processing program.
Electron beam melting (EBM) is a process method in which an electron beam is used as a heat source in a vacuum environment to melt the metal powder layer by layer to add materials. Its working principle is: pre-powdering, high-energy electron beam after focusing to produce high-energy deflection in the local micro-region to produce a high temperature and even the melting of the powder layer, the continuous scanning of the electron beam to generate energy so that the molten pool between the fusion and solidification, Connected into linear and planar metal layers. After the current layer is processed, repeat the powder coating operation until it is formed. In the production process, EBM uses a vacuum melting environment to ensure both the high strength of the material and the oxidation of the alloy. Compared with SLM, the main advantages of EBM are: Efficiently generated electron beam power consumes less power and has a higher output rate, so that the total actual power of the whole machine is high; the deflection of the electron beam does not need to move the parts of the equipment, further improving the scanning speed; The thermal environment enables the dimensional stability of 3D printed parts to be guaranteed, and their static mechanical properties are guaranteed to meet biological requirements, and metal powders can also be recycled.