Future in powder

Swedish company VBN Components produces steel products using additive technologies using powder with additives, mainly tools such as drills and milling cutters. 3D printing technology eliminates the need for forging and machining, reduces raw material consumption, and provides end users with a wider choice of high-quality materials.

The offer of VBN components includes eg. Vibenite 290which, according to the Swedish company, is the hardest steel in the world (72 HRC). The process of creating Vibenite 290 is to gradually increase the hardness of materials up to. Once the desired parts are printed from this raw material, no further processing other than grinding or EDM is required. No cutting, milling or drilling required. Thus, the company creates parts with dimensions up to 200 x 200 x 380 mm, the geometry of which cannot be produced using other manufacturing technologies.

Steel is not always needed. A research team from HRL Laboratories has developed a 3D printing solution. aluminum alloys with high strength. It is called nanofunctional method. Simply put, the new technique consists in applying special nanofunctional powders to a 3D printer, which are then “sintered” with a laser thin layers, which leads to the growth of a three-dimensional object. During melting and solidification, the resulting structures are not destroyed and retain their full strength due to the nanoparticles acting as nucleation centers for the intended microstructure of the alloy.

High-strength alloys such as aluminum are widely used in heavy industry, aviation (eg fuselage) technology and automotive parts. The new technology of nanofunctionalization gives them not only high strength, but also a variety of shapes and sizes.

Addition instead of subtraction

In traditional metalworking methods, waste material is removed by machining. The additive process works in reverse - it consists of applying and adding successive layers of a small amount of material, creating XNUMXD parts of almost any shape based on a digital model.

Although this technique is already widely used for both prototyping and model casting, its use directly in the production of goods or devices intended for the market has been difficult due to low efficiency and unsatisfactory material properties. However, this situation is gradually changing thanks to the work of researchers in many centers around the world.

Through painstaking experimentation, the two main technologies of XNUMXD printing have been improved: laser deposition of metal (LMD) and selective laser melting (ULM). Laser technology makes it possible to accurately create fine details and obtain good surface quality, which is not possible with 50D electron beam printing (EBM). In SLM, the tip of the laser beam is directed onto the powder of the material, locally welding it according to a given pattern with an accuracy of 250 to 3 microns. In turn, LMD uses a laser to process the powder to create self-supporting XNUMXD structures.

These methods have proven to be very promising for creating aircraft parts. and, in particular, laser deposition of metal expands the design possibilities for aerospace components. They can be made from materials with complex internal structures and gradients not possible in the past. In addition, both laser technologies make it possible to create products of complex geometry and obtain extended functionality of products from a wide range of alloys.

Last September, Airbus announced that it had equipped its production A350 XWB with additive printing. titanium bracket, manufactured by Arconic. This is not the end, because Arconic's contract with Airbus provides for 3D printing from titanium-nickel powder. body parts i propulsion system. However, it should be noted that Arconic does not use laser technology, but its own improved version of the EBM electronic arc.

One of the milestones in the development of additive technologies in metalworking is likely to be the first-ever prototype presented at the headquarters of the Dutch Damen Shipyards Group in the fall of 2017. ship propeller metal alloy named after VAAMpeller. After appropriate tests, most of which have already taken place, the model has a chance to be approved for use on board ships.

As the future of metalworking technology lies in stainless steel powders or alloy components, it is worth getting to know the major players in this market. According to the "Additive Manufacturing Metal Powder Market Report" published in November 2017, the most important manufacturers of 3D printing metal powders are: GKN, Hitachi Chemical, Rio Tinto, ATI Powder Metals, Praxair, Arconic, Sandvik AB, Renishaw, Höganäs AB, Metaldyne Performance Group, BÖHLER Edelstahl, Carpenter Technology Corporation, Aubert & Duval.

Propeller print WAAMpeller

Liquid phase

The most well-known metal additive technologies currently rely on the use of powders (this is how the aforementioned vibenite is created) "sintered" and laser-fused at the high temperatures required for the starting material. However, new concepts are emerging. Researchers from the Cryobiomedical Engineering Laboratory of the Chinese Academy of Sciences in Beijing have developed a method 3D printing with "ink", consisting of a metal alloy with a melting point slightly above room temperature. In a study published in the journal Science China Technological Sciences, researchers Liu Jing and Wang Lei demonstrate a technique for liquid-phase printing of gallium, bismuth, or indium-based alloys with the addition of nanoparticles.

Compared to traditional metal prototyping methods, liquid-phase 3D printing has several important advantages. First, a relatively high rate of fabrication of three-dimensional structures can be achieved. In addition, here you can more flexibly adjust the temperature and flow of the coolant. In addition, liquid conductive metal can be used in combination with non-metallic materials (such as plastics), which expands the design possibilities for complex components.

Scientists at American Northwestern University have also developed a new metal 3D printing technique that is cheaper and less complex than previously known. Instead of metal powder, lasers or electron beams, it uses conventional oven i liquid material. In addition, the method works well for a wide variety of metals, alloys, compounds, and oxides. This is similar to the nozzle seal we know with plastics. "Ink" consists of a metal powder dissolved in a special substance with the addition of an elastomer. At the time of application, it is at room temperature. After that, the layer of material applied from the nozzle is sintered with the previous layers at an elevated temperature created in the furnace. The technique is described in the specialized journal Advanced Functional Materials.

Chinese Liquid Metal Phase Printing Method

In 2016, Harvard researchers introduced another method that can create XNUMXD metal structures. printed "in the air". Harvard University has created a 3D printer that, unlike others, does not create objects layer by layer, but creates complex structures "in the air" - from instantly freezing metal. The device, developed at the John A. Paulson School of Engineering and Applied Sciences, prints objects using silver nanoparticles. The focused laser heats the material and fuses it, creating various structures such as a helix.

Market demand for high-precision 3D printed consumer products such as medical implants and aircraft engine parts is growing rapidly. And because product data can be shared with others, companies around the world, if they have access to metal powder and the right 3D printer, can work to reduce logistics and inventory costs. As is known, the described technologies greatly facilitate the manufacture of metal parts of complex geometry, ahead of traditional production technologies. The development of specialized applications is likely to lead to lower prices and openness to the use of 3D printing in conventional applications as well.

The hardest Swedish steel - for 3D printing:

The hardest steel in the world - made in Uppsala, Sweden

Aluminum film for printing: 

Breakthrough in metallurgy: 3D printing of high-strength aluminum