Design of gyroidal structures for heat exchanger applications, manufactured with binder jetting using copper

The thermal management of modern vehicle systems requires the use of high-performance heat exchangers that are also designed to be compact to guarantee the best possible integration into the overall system architecture. In this context, additive manufacturing opens up the possibility of using more complex structures to generate larger exchange surfaces and a 3D fluid flow using gyroid structures. Binder jetting is a process that has great potential for these applications, as its fast build rates and scalability make it suitable to produce medium quantities and easy processing of Cu. However, to enable its broad transfer of this technology to industry and to ensure the applicability of the process, it is necessary to better understand the process in terms of its production limits regarding thin-walled structures. In this work, the design limits of gyroid structures were evaluated with respect to their suitability for depowdering using various test geometries. An evaluation method was presented that makes it possible to relate the depowdering of samples to the respective slices based on CT-images. It was found that the gyroid design parameters have a decisive influence on the depowdering of the manufactured components. ... mehrIt was shown that the depth effect of compressed air during the depowdering step is limited and becomes more difficult with scaled component dimensions. In addition, the depth effect decreases with increasing wall thickness and decreasing unit cell size. However, stretching the unit cell of the gyroid structures along the depowdering direction has proven to be positive.