Relevant Information:Power bed fusion of metals using a laser beam (PBF-LB/M) offers unique possibilities to manufacture functionally graded materials (FGM) consisting of different alloys. These so-called multi-material parts enable their material properties to be tailored to local material requirements. The Aerospike was manufactured on a customized SLM 280HL PBF-LB/M machine (Nikon SLM Solutions AG, Germany). The system has a divided recoating system and a suction unit to apply and remove different powder materials. After applying and solidifying the first material, it is removed by the suction unit and the second material can be deposited and solidified without moving the z-axis. Only after the second material is removed by the suction unit, the build platform is lowered and the process is repeated for the next layer.

The Aerospike as a concept dates back to the 60s with first prototypes built by NASA, Rocketdyne, etc. in the 70s. Traditional rocket engines use large bell nozzles to expand the supersonic exhaust flow in order to generate thrust. Aerospikes are “inverted” nozzles with a spike in the center, which adjust much better across changing ambient pressures during atmospheric ascent while being more compact and lightweight. A functional Aerospike engine promises between 15 to 20 percent performance advantage over conventional engines. However, such an Aerospike engine has never flown successfully up to this date and the original prototypes never left the test stands. Aerospikes pose a couple of true engineering challenges – mainly connected to their tendency to overheat – that could not be overcome using the design and manufacturing methods from the past. However, with the advent of Additive Manufacturing and Computational Engineering, this statement might no longer hold true…
In addition to the engineering domain knowledge, LEAP 71’s algorithms take manufacturing limitations and opportunities into account. Typically, we would constrain overhang angles and wall thicknesses to guarantee printability on any given 3D-printer. However, the Fraunhofer IGCV has developed a very capable dual-metal SLM-based process that enables 4D designs, objects with a purposeful material distribution enabling an unmatched level of functional integration. Computational Engineering is again a powerful tool to handle such a multi-material design. This is why the team from Fraunhofer IGCV in Augsburg and LEAP 71 have started to collaborate on the intersection of their technologies to push the boundaries of what additively manufactured objects can be.

Chemical Composition: Material combination consiting out of copper alloy CW106C and tool steel 1.2709