and a bit further along the path ... ;0)
Chinese scientists develop first ever 3D printing, casting and forging all-in-one technique
Jul 22, 2016 | By Benedict
A team of scientists in China has developed a metal 3D printing technology called “smart micro casting & forging.” The technology combines 3D printing and forging, uses metal wire “1/10 the cost” of AM powders, and could be used in the aerospace, automotive, and molding industries.
Under the leadership of Zhang Haiou, Professor of Mechanical Engineering at Huazhong University of Science, a team of scientists in China has—after 10 years of research—developed what could prove to be a game-changing form of metal manufacturing. A combination of 3D printing, casting, and forging, the new method claims to have “broken the biggest obstacle facing the 3D printing industry,” bringing a disruptive technological innovation to global machinery manufacturing.
Additive manufacturing is becoming a more and more popular choice for metal parts across a wide range of industries, but doubts remain over the structural integrity of certain 3D printed components. Advocates of traditional manufacturing methods cite the porosity, lack of fusion, and other problems associated with 3D printed parts as a reason to stick with casting or forging techniques.
The Micro Forging & Casting Sync Composite Device, a new product developed by Zhang Haiou and his team, offers an alternative to metal 3D printing methods like selective laser melting and sintering, combining 3D printing, casting, and forging in one. This amalgamation of techniques contributes to increased part strength and toughness, improved product lifecycle, and higher reliability. According to its developers, the technology can also be used to create thin-walled metal components while eliminating excess material and equipment costs.
The all-in-one micro-casting-forging-milling manufacturing equipment currently being developed by the scientists will be capable of producing metal forging parts up to 5.5 × 4.2 × 1.5 m in size, with a surface roughness of 0.02 mm—the level of general machining processing. The team has, however, already developed a machine capable of 3D printing in eight kinds of materials, including titanium alloy, for aircraft and marine use, and steel, for use in nuclear power stations. This machine has built a part 2.2 m long and weighing 260 kg. It has also successfully 3D printed a forging part measuring 1800 × 1400 × 50 mm.
In traditional mechanical manufacturing, cast metal can not be directly processed into high-performance parts. Its internal structure must be improved through forging, while molding problems also need to be solved. Large forging machinery can be costly, however, and implementation of such equipment results in a long production process, huge energy consumption, serious pollution, and serious waste. Furthermore, it remains difficult to produce functionally gradient material parts. As a burgeoning technology, conventional metal 3D printing technology can solve the above shortcomings of the traditional system, making it a valuable technology in the aerospace, automotive, and molding industries.
Zhang Haiou commented: “In the past, conventional 3D printing has been fatally flawed in the following areas: first, without forging, metal parts have a serious chance of wearing; second, the performance of 3D printed parts has not been high; a third problem is the presence of pores and unfused portions; and the fourth is that using a laser or electron beam as a heat source is very costly.”
Experts have verified that parts made by 3D printing, casting and forging all-in-one technique are more stable than those made by traditional casting. Furthermore, the Chinese scientists say that the new technique is 80% more efficient than SLM 3D printing, with material costing around one-tenth that of metal additive manufacturing powders. The material used in the forging and casting technique is a kind of metal wire, which is heated by an energy-efficient electric arc which uses one-tenth the energy of a laser beam. This method, which can simultaneously control the size and shape of performance parts, can reportedly save time as well as energy, with two-ton metal castings taking only 10 days to produce, previously three months.
The casting and forging process has already been used to create a titanium 3D printed joints for a new fighter aircraft, which would have been impossible to create as a single piece using any subtractive manufacturing technique. In the past, the only method was to reduce the design standards, split it into multiple parts, and then assemble it, affecting the performance of the fighter and shortening its life cycle. Zhang Haiou and his team have used their new technology to 3D print TC4 titanium alloy parts whose tensile strength, yield strength, ductility, and toughness are much better than the traditional forging parts.
A number of experts, including former Chinese Minister of National Aerospace Lin Zongtang, have suggested that the technology could feature in the Made in China 2025 initiative, a national project inspired by Germany’s “Industry 4.0” scheme which will attempt to “comprehensively upgrade Chinese industry.” The initiative will focus on promoting technology and equipment in aerospace, military and civilian planes, nuclear power applications, ships, high-speed rail and other key areas, so that the technology can improve the country's manufacturing capacity and defense strength. |
