Forming technology, metal-cutting and process engineering require extremely hard tools that are conventionally made by powder pressing. A 3D printing process known as fused filament fabrication offers a more cost-effective method of producing even harder, custom tools.
A hard metal sample with a complex geometry on an FFF Hage3D 140 L standard printer in which larger components can also be printed in future.
Fraunhofer IKTS
Hard metals consist of nickel or cobalt metal binders, as well as tungsten carbide. Until now, this material was used for producing reliable cutting, drilling, pressing and punching tools by extrusion, injection moulding, or uniaxial or cold isostatic powder pressing. However, these processes make it very difficult or even impossible to realise complex or specific geometries despite expensive post-processing. Additive manufacturing processes can provide a solution: 3D powder printing (binder jetting) and thermoplastic 3D printing (3DTP) with select hard metal compositions have already been successfully implemented at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS. However, this method restricts the size of the component, as well as the adjustment of the binder content and hence the resulting hardness.
Fused filament fabrication – cost-effective and customised production
Stemming from the plastic processing industry, the fused filament fabrication (FFF) additive manufacturing process was initially adapted for ceramics and composite materials at IKTS in Dresden. "The material-efficient FFF also opens up interesting possibilities for the production of large, complex prototypes or special tools made of hard metals," reports IKTS shaping expert Dr. Tassilo Moritz. During FFF, 3D bodies are manufactured from a flexible, meltable filament. IKTS has managed to produce the necessary filament for FFF using hard metal powders combined with organic binders. Depending on the material structure, a reduced grain size and modified binder content can be used to specifically increase the hardness, as well as the compressive and flexural strength, of hard metals. Dr. Johannes Pötschke, head of the Hardmetals and Cermets group at IKTS, confirms: "The filaments can be used as semi-finished products in standard printers and, for the first time, make it possible to print hard metals with a very low metal binder content of only eight percent and a fine grain size below 0.8 micrometres and thus allow extremely hard components with up to 1700 HV10."