ESA-supported startup TIWARI Scientific Instruments has been successful in 3D printing complex geometries using a pure copper material with their RAPTOR bound filament extrusion (FFF) 3D printer, obtaining high-density, oxygen-free copper parts. Samples of these high-resolution parts are shown in the images above and below. They include heat exchangers, which were designed using nTopology, simulated through SimScale and manually optimized for performances.

Copper has long been on the wishlist of AM adopters and its potential use for heat exchangers—due to its high thermal conductivity—has been well documented. However, processing pure copper either as a powder or as a filament has proven extremely challenging.

Recent developments in the field of Copper AM, have seen green lasers successfully deployed for the production of 3D printed copper parts using laser Powder Bed Fusion (L-BPF). However, improvement in surface finish for demanding applications may require additional machining/post-processing and this might affect the purity of the copper parts post-treatment. With FFF, the parts can be printed with a layer thickness of around 50 μm. After sintering the roughness due to layer thickness tends to be even lower due to shrinkage. In addition, the parts can be manually polished in “green-state” thus further reducing the cost associated with post-processing.

TIWARI’s EAM technology is suitable for the cost-effective production of both ceramic and metal parts using Fused Filament Fabrication (FFF) technology. The process uses specially fabricated bound metal or ceramic filaments which are shaped into desired geometry using specially developed in-house FFF printers. The printed “green parts” may then be machined in order to include further details in the parts and to improve surface finish, after which they are subsequently heat-treated at high temperatures to eliminate the binder and to sinter the part. The RAPTOR yields both metal and ceramic parts with a relative density of over 99%.

TIWARI currently supports both metals, including Copper, Stainless Steel (316L & 17-4PH), Titanium (Ti6Al4V), and ceramics, including Alumina (Al2O3), Silicon Carbide (SiC), Silicon Nitride (Si3N4), Tungsten Carbide-Cobalt (WC-Co), Zirconia (ZrO2), Molybdenum disilicide (MoSi2). The company TIWARI also performed a qualification campaign for its metal and ceramics together with ESA.