Introduction: Screen printing is an industrially established high-throughput technology widely used in the manufacturing of solar cells, electronic circuit boards, gaskets, and so on. It offers the possibility to print layers with high resolution (down to 50 µm), accuracy (±25 µm) and thickness (5 to 50 µm). Based on this technology, a 3D screen printing process has been developed that offers interesting features for the additive manufacturing of metallic parts such as intricate geometrical details and smooth surfaces as well as closed cavities within the part. Figure 1 shows the process route of 3D screen printing.
In 3D screen printing, the printing cycle is repeated many times, layer by layer is added until parts have reached their designated height. The printing paste contains a high volume of solid metal particles. Once the printing process has been finished, a heat treatment is carried out which removes the binder and eventually leads to dense metallic parts by sintering. Copper is an interesting material system for additive manufacturing, due to its high electrical and thermal conductivity. It is difficult to process in beam assisted 3D printing processes like SLM due to the high reflectivity of the copper powder .A feasibility study has been carried out for additive manufacturing of fin-type heat exchangers from copper by this approach. The goal was to print a compact water-air heat exchanger with a very small fin spacing on the air side and include the manifold for the water side into the print.
Authors: Kay Reuter, Marcus Rohne, Thomas Studnitzky, Olaf Andersen, and Bernd Kieback
Keywords: 3D Printing, Screen Printing, Heat Exchanger