Jul 25, 2016 | By Alec

The Chengdu J-20.

Just last week, a team of Chinese researchers from the Huazhong University of Science unveiled a truly remarkable 3D printer that could change metal manufacturing altogether: the all-in-one casting and forging metal 3D printer. This revolutionary machine combines 3D printing, casting and forging in a single device, and produces high quality results while eliminating excess material and equipment costs. It thus certainly has the potential to be used in just about any industry, but Chinese aviation specialists are the first to adopt it and are using this 3D printer to produce critical parts for China's fifth generation fighter jets, including the stealthy Chengdu J-20 and the Shenyang J-31.

Of course this is by no means the first time the Chinese government applied 3D printing to military production; Chinese warships first started taking 3D printers to sea back in early 2015 with an eye on emergency repairs. But the fact this new 3D printer is already used for critical part production showcases its usefulness and reliability.

The 3D printer itself was developed under the leadership of Zhang Haiou, Professor of Mechanical Engineering at Huazhong University of Science. Upon its unveiling, he claimed to have “broken the biggest obstacle facing the 3D printing industry.” This disruptive technological is especially remarkable for realizing an increased part strength and toughness (compared to other technologies), an 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. Relying on an affordable electric arc as a heat source and low-cost metal wire as a raw material, it features a utilization rate of up to 80% or more – whereas traditional techniques are lucky to reach 5%. Of course the need for large casting, forging and milling equipment is also removed – as all processes are directly controlled through the 3D printer – to further reduce the need for investments.

What’s more, the 3D printer is very large and open to a wide range of materials. The first iteration of this hardware can work with eight kinds of materials, including titanium alloy, for aircraft and marine use, and steel, for use in nuclear power stations. This machine has already successfully built a part that 2.2 m long and weighs 260 kg, as well as a forging part measuring 1800 × 1400 × 50 mm. An even larger version of the 3D printer is already under development.

Professor Zhang Haiou and his wife professor Wang Guilan

But the all-in-one casting and forging metal 3D printer is also remarkable for one other reason: the 60-year-old professor Zhang Haiou developed it in collaboration with his wife professor Wang Guilan, 53, who teaches at the same university. Together, they have been working on metal manufacturing techniques for more than 18 years, and they frequently clashed about it. Back in 2008, they even had a fight about Zhang Haiou’s proposal to integrate casting, forging and milling in a single machine – which his wife called a fantasy. “I do not blame her, as casting, forging, milling have existed as separated technologies for thousands of years,” the professor recalled.

But the quarrel did open their minds an led to a series of experimentations with a team of students. “At that time I thought that if it does not work, at least he could just give up,” his wife recalled. “Although I often criticize his failed tests, I still unconsciously use his methods for testing. When it’s wrong, we start arguing, but try again soon.” The couple spend most of their time working on R&D.

The Shenyang J-31.

While the researchers themselves previously said that their innovations will be especially useful in the aerospace, manufacturing and automotive industries, the Chinese defense sector could not pass up on this technology either. Several parts for Chinese fighter jets (understood to be the Chengdu J-20 and the Shenyang J-31) have already entered limited production, with all parts made in a single piece – which would’ve been impossible using subtractive manufacturing methods or other metal 3D printing solutions.

That is a very important breakthrough, as multi-part geometries are believed to negatively affect performance and life cycles. The parts themselves are 3D printed in TC4 titanium alloy, resulting in excellent tensile strength, yield strength, ductility and toughness properties. Experts already verified that the parts are more stable than those made by traditional casting. And with a squadron of twelve J-20 heavy stealth fighters featuring these parts expected to be completed in 2017, it looks like metal 3D printing is also becoming an integral part of China’s defense industry.

Posted in 3D Printing Applications

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kb wrote at 7/29/2016 12:29:50 AM:One day they're going to discover that they can 3d print casts to mold this kind of basic metal parts and use way less energy!



