3D Systems Debuts a Huge Metal Production Printer

3D Systems has launched the latest in its series of ProX Direct Metal Printing (DMP) printers: the DMP 320. Built on the same architecture as previous ProX DMP machines, the 320 has been optimized to build high volumes of industrial components for the medical, aerospace and automotive industries.

According to 3D Systems’ COO, Kevin McAlea, the DMP 320 has been developed with industry partners in an effort to create a trail-blazing production machine. In fact, during the process of developing the DMP 320, 3D Systems, in conjunction with its own customers, has already printed over half a million test parts on their way to honing their newest system. “We’ve been working closely with leading customers through extensive beta testing of this machine, and the feedback we have received distinguishes this printer as one primed to transform expectations for timelines, process and results.” Said McAlea.

One of the many key features that sets the DMP 320 apart from other metal printers is its ability to produce prints with low oxygen exposure, lending parts greater strength and improved chemical purity. Additionally, the DMP 320 can be outfitted with quick-swap build modules that allow users to pull finished prints from the machine and load in a new powder bed to jumpstart a new print process. With this feature, the delicate and painstaking job of removing excess powder and supports can be completed without delaying the next print run.

How the ProX DMP 320 Works

The DMP 320 builds parts in much the same way that all other printers in the DMP line do—it uses a laser to sinter metal powders into a solid part, layer by layer.

To begin the print process, the DMP 320 is loaded with a build module that contains either a nickel alloy, titanium alloy or stainless steel powder base. Once the material has been loaded into the machine, the printing process can begin. Using a high-power laser, the DMP 320 fuses its metal powder stock to form the geometry of a component one layer at a time. Once a layer has been completed, the machine’s build platform is lowered by one layer thickness and additional powder is added to the build platform. With a new layer of powder in place, the printing process begins anew and continues the same choreography until a print is complete.

With a completed print, any subsequent processing such as hardening, texturing or painting can be applied to the component to complete production.

The ProX DMP 320 in Action

The European Space Agency (ESA) is one of the largest space agencies on the planet and is tasked with overseeing everything from launch operations in French Guiana to research and development in a number of countries.

One of the agency’s biggest R&D priorities is, of course, engine technology. While a number of engine types are employed in launching payloads to Earth’s orbit and beyond, the ESA has had special focus on satellite propulsion.

In a conventional satellite engine, propulsion is generated by combining two propellants together in a controlled manner so that they combust spontaneously and continuously. Key to this mixing arrangement is the geometry of the injection manifold. The ignited propellant is then accelerated in the combustion chamber to power the rocket. An ESA research program was established to investigate how DMP could be leveraged to improve injector design.

“DMP offers innovative manifolding to optimize the flow from the propellant valve to the combustion chamber,” said ESA propulsion specialist Simon Hyde.

The ESA’s redesigned injector proved that DMP could deliver a space-worthy integrated design with fewer parts (reducing five parts to one), lower cost and reduced tooling. In a second investigation, the ESA wanted to determine if DMP could also be used to produce a lighter weight, yet equally efficient, combustion chamber.

Today, most combustion chambers are built to withstand a number of forces that have nothing to do with operation while in space. In fact, all engine chambers are designed with extremely thick walls so that they can withstand the transient nonoperational forces that occur during a rocket launch. Because of this extra heft, satellite launches are more expensive.

In an effort to reduce cost, Hyde and his team used the 320’s DMP process to build low-density combustion chamber walls from Ti6Al4V that could maintain the strength required for launch while dramatically reducing weight.

Using an intricately patterned mesh that could only be built via additive manufacturing (AM), the ESA was able to slash the overall material density of the chamber to 12 percent of its original weight. Further study will examine how this revolutionary mesh design influences the thermal performance of the new combustion chamber.

A third exploration involved investigating how DMP could also be used for the rocket’s expansion nozzle, a large part conventionally produced by the spin-forming of sheet metal with a diameter approaching 50 cm. The DMP process produced a titanium part that meets the requirements of the conventionally produced equivalent, while maintaining design flexibility not possible with the original.

In the end, by using the DMP 320, Hyde and his team at the ESA were able to cut the cost, weight and assembly complexity of producing their engine components. Although that might not seem like a big deal, it’s a major achievement—particularly when you consider how robust an off-world propulsion system has to be if it’s going to be in service onboard a satellite for decades.