Although not all companies have come across 3D printing, it is already preparing its next offensive. The machines will be faster, more accurate, and will allow repairing parts made with other techniques.
The 3D printing market is growing at an incredible speed. Over the past 24 months, many companies have announced new technologies and machines, presenting an intriguing future ahead of us in the industrial world. Additive techniques, where metal is the building block, are slowly becoming the standard, and prices for such services are dropping every month. Plastic printing takes less time and is successfully starting to work on a mass scale. The market trend is unmistakable – printers have taken hold in the industry for good and are becoming basic machines not only in research and development offices, but also in production halls.
FDM, SLA or SLS?
Today, technologies invented decades ago are still used in the main. It is thanks to the falling prices of equipment and its components that additive techniques have become so popular in recent years. The technology most commonly used by home printers is FDM (Fused Deposition Modeling) sometimes called FFF (Fused Filament Fabrication). In this method, a solid material (filament) is forced through a heated nozzle where it melts. The head travels along a defined path on the work platform, leaving a thin strip of material that solidifies quickly. Once the path mapping the base of the part is completed, the platform moves away from the nozzle and the nozzle begins applying the next layer
SLA (Stereolithography) uses a completely different way of solidifying the plastic – photopolymerization. This method is similar to FDM – it consists in curing successive layers of the object moving lower and lower on a moving table. Most importantly, SLA uses a liquid material. A UV lamp, or LCD screen, illuminates a mirror of the liquid resin along a specific path and cures it. Another layer of builder is then applied and so on
SLS (Selective Laser Sintering) is a method that uses a plastic powder that is sintered using a laser beam. This technology makes it possible to print extremely robust parts with complex geometries. A 0.1-millimeter layer of powder is deposited on a work platform and the laser beam passes over it, following a working path defined by the base of the object to be printed. Then, as in other methods, the platform is lowered and the system applies another layer of powder. Once the process is complete, the structure needs to be blown free of residual material and the object is ready.
Mega-fast printing in metal
Of course, there are dozens of variations of the methods described above, but these are the most popular and best represent the idea of additive technologies – that is, adding layers of material to make a complete solid. Printing in metal works similarly, although here the matter is more complicated. Technologies connected with this branch of industry are closest to SLS, i.e. printing an object by sintering successive thin layers of metal powder. So far, these methods have been very slow, but this wants to change with Australian company Aurora Labs, which talks about printing up to one ton of metal per day. While this sounds fantastic, back in 2018 the company reported that it was able to sinter around 30 layers of material with a single pass of the print head, achieving a total of 113 kilograms per day
MCP (Multilevel Concurrent Printing) has two key components: a grating-like coating mechanism and a multiple laser beam system. The head is equipped with several trays that apply different layers, and a separate laser is responsible for curing each layer. MELD is a technology that allows metal to be printed without melting. The material does not change its state of aggregation and does not overheat – instead, it is injected under tremendous pressure. The metal powder or wires are passed through a hollow, rotating tool that presses it into the space beneath it through helical motions, pressure and friction. A huge advantage of this technology is that there is no need for heat treatment on the printed objects. Moreover, this method can be used not only to manufacture parts, but also to repair or coat existing parts
New technologies in 3D printing are not only more efficient nozzles, new materials and industrial systems of printing in metal. VELO3D has focused on developing software that will optimize 3D printing by maximizing the integration of hardware and software. The Sapphire 3D printer is based on sintering metal powder, but it is also richly equipped with sensors, responsible for precise control of the currently sintered surface in a closed-loop control system. Besides, its software for preparing models for printing allows to simulate the process of creating an object, allowing to predict possible errors and correct problematic structures of the element.
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