April AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | A P R I L 2 0 1 9 6 8 3D PRINTSHOP TITANIUM SUITED FOR SPACE The first full-scale prototype of a titanium pressure vessel to be used in future manned missions for space exploration was produced by a team from Thales Alenia Space, Cranfield University, and Glenalmond Technol- ogies, UK. The piece is approximately 1 m in height and 8.5 kg in mass. Made of Ti-6Al-4V, it was deposited using the wire plus arc additive manufacturing (WAAM) process, which Cranfield Uni- versity pioneered. By going straight fromdigital draw- ing to final structure, WAAM integrates two individual pieces into a single part, eliminating the need for long-lead-time forgings, and reduces the amount of waste material to be removed by ma- chining. If manufactured traditionally, the component would have required about 30 times more raw material than its final mass. The WAAM process saved more than 200 kg of Ti-6Al-4V per item. The team is now building a second prototype, which will help to fine-tune the entire manufacturing cycle, demon- strate process repeatability and reliabil- ity, and push the implementation of the new approach into the flight hardware. Massimo Chiampi, study manager for AM projects at Thales Alenia Space, explains, “A near-net-shape item is fab- ricated in a few days—compared to several months needed for the procure- ment of the standard wroughtproducts.” www. thalesgroup.com/en. SEAMLESS PRINTING Additive manufac- turing of large-volume plastic components is a time-consuming under- taking. Researchers at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in Chemnitz, Germany, have now de- veloped screw extrusion additive man- ufacturing (SEAM), a system and pro- cess they say is eight times faster than conventional 3D printing. The process achieves this ultra-fast production speed by combining 3D printing with the motion system of a machine tool. The system’s high-speed technology requires only 18 minutes to produce a plastic component that is 30 cm high. Tool manufacturers as well as the auto- motive and aerospace industries could benefit from this innovative 3D printer. The hot plastic is deposited in layers on the platform. The motion system of the machine ensures that the con- struction panel slides along under the nozzle in such a way that the previously programmed component shape is pro- duced. SEAM allows researchers to im- plement complex geometries without supporting structures. The highlight is that the new system even makes it possible to print on existing injection- molded components. www.fraunhofer. de/en. TWO TECHNIQUES, ONE STUNNING IMAGE This colorful microscopic view of a single piece of space-quality Inconel superalloy was processed using two different 3D printing techniques. The image is a close-up of the boundary layer between them. The left side was produced using direct energy deposi- tion based on laser melting of metal powder feedstock, while the right side was made through powder bed fu- sion. This micrograph of the resulting hybrid part is based on electron back- scatter diffraction (EBSD). The patches reveal different grains and the various colors depict the orientations of these grains. The part was produced during a European Space Agency general sup- port technology program project with Balmar and the Institute of Metals and Technology in Slovenia. www.esa.int. EBSD view of a hybrid 3D-printedmetal part. Courtesy of Balmar/Institute of Metals and Technology, Slovenia. SEAM can accelerate the additive manufacture of plastic components eightfold over conventional processes. Courtesy of Fraunhofer IWU. To process the plastic, the re- searchers use a specially designed unit that melts the raw material and ejects it at a high output rate. This unit is in- stalled above a construction platform that can be swiveled in six axes by using the motion system of a machine tool.