Mitsubishi Heavy Industries to Expand DED Metal 3D Printing Line

Slowly, but surely, mainstream industrial manufacturers are taking over the 3D printing space. While there was talk maybe eight years ago about whether or not HP would be acquiring Stratasys or 3D Systems, we’ve since seen the 2D printer manufacturer disrupt the 3D printing industry.

And, though the manufacturing giant might not conquer all of additive manufacturing (AM), Mitsubishi is sure to have an impact on 3D printing, as well. While subsidiary Mitsubishi Chemical is making inroads into the materials space, the larger Mitsubishi Heavy Industries is also increasing its presence in metal AM with a specific focus on directed energy deposition (DED). At Formnext Connect, I spoke to Alexander Spatzig, Head of Business Development at Mitsubishi Heavy Industries Europe, Ltd., who provided insight into the company’s own DED process and products.

Mitsubishi entered the 3D printing space when, in 2014, the Japanese government recognized that the country was a bit behind other leading countries in the additive space. In turn, all of the large Japanese manufacturers got together to develop their own 3D printing technologies. The technology from Mitsubishi Heavy Industries was created under a research project under Japan’s New Energy and Industrial Technology Development Organization (NEDO), with the participation of the Technology Research Association for Future Additive Manufacturing (TRAFAM).

As a manufacturer of industrial machinery, Mitsubishi Heavy Machinery produces injection molding equipment, machine tools, compressors and paper and printing machinery. Like other machine tool makers, Mitsubishi was able to jump into 3D printing by incorporating a DED laser head, capable of 6 kW power output, into an existing milling machine.

This resulted in the first of its LAMDA line of DED 3D printers, a research-oriented system dut. This DED printer has a build volume of just 200 mm x 200 mm x 200 mm, but Spatzig explained that they are developing a DED system for 3D printing parts up to 2.5 m on a side. The Mitsubishi site lists sizes ranging from that smaller LAMDA200 model to a 2,500mm ×900mm ×1,000 mm LAMDA2000 model.

Developing a DED system isn’t as simple as just plopping a laser into a CNC machine. For instance, providing the proper atmospheric conditions in which the laser can melt metal powder is necessary. In the case of Mitsubishi, a specialty nozzle was created that generates a local atmosphere of argon gas, allowing the company to be able to scale up the technology without requiring a larger enclosed chamber that would obviously not be cost effective at some point. The printer also includes a real-time monitoring system that allows for closed-loop control of the process through the use of artificial intelligence software that corrects the build if it deviates from the intended design.

“The system checks, for example, the heat and the size of the melt pool, and then immediately regulates the laser power so that it doesn’t become over-melted. It doesn’t become bigger than it should be,” Spatzig said.

Another added benefit is that the LAMDA line includes hybrid manufacturing, in which a CNC head can be used to mill the DED part to completion, or perform processing before part printing begins. Some users of hybrid metal 3D printers have noted how it is not always easy to switch from DED to milling or another subtractive process without first performing some post-processing, such as hot isostatic pressing, on the printed part without the risk of cracking or deformation. However, Spatzig explained that the in-process monitoring to prevent such outcomes.

An exhaust duct for an aircraft. The part measures 130mm×120mm×80mm and is made from Ti6A14V titanium. Produced in 10 hours.

A large-scale turnkey solution will likely not be available on the market for another two to three years, within the next year, customers will be able to work with the company to develop custom solutions. This is made easier by the fact that Mitsubishi can convert its existing manufacturing equipment into DED machines.

As a roughly $39B company (in 2017), Mitsubishi Heavy Industries is a part of the Mitsubishi Group alongside the general trading company Mitsubishi Corporation, Mitsubishi Electric and MUFG Bank, the largest bank in Japan. Mitsubishi Heavy Industries itself was the 23^rd largest defense company by revenue globally in 2011 and includes such widely known subsidiaries as Nikon and Mitsubishi Motors.

Mitsubishi Electric has developed its own DED process that it refers to as a “dot forming technology”, a wire-based method that relies on a pulsed laser and minimum heat input. Though this technology may use less expensive feedstock but will also result in less precise parts before post-processing than blown powder DED. However, Mitsubishi Electric claims that geometric accuracy is 60 percent greater than “traditional DED.” The company was aiming to launch the platform in 2021.

While Mitsubishi Electric may have its own DED process, Spatzig was quick to differentiate the different segments of the Mitsubishi Group, saying they all operated independently and even competed with one another on occasion.

“For example, Mitsubishi Electric is a direct competitor in some cases. They make air conditioners, just like us,” he pointed out. “So, Mitsubishi Electric isn’t even part of the same conglomerate as Heavy Industries. Especially if you’re dealing with intellectual property or NDAs, then we really have to be careful.”

Meanwhile, Mitsubishi Chemicals, which is a part of Heavy Industries, has increased its stake in 3D printing materials production, in part through the acquisition of Dutch Filaments and the launch of a pilot 3D printing service in partnership with AddiFab.

Recently this year, Warren Buffett made a $6 billion investment into five of Japan’s oldest trading companies, which included Mitsubishi Corp (separate from Electric and Heavy Industries). If there really is a relationship between the various businesses under the Mitsubishi Group umbrella, then it’s possible that they may become a force to contend with in the 3D printing industry.

(Images courtesy of Mitsubishi Heavy Industries.)