Extrusion of powder-based materials

Extrusion is one of the most common shaping processes for producing elongated structures with constant, often complex cross-sections. Products produced by extrusion include tubes, hoses, or even V-belts and toothed belts. In its research work, Fraunhofer IFAM focuses, among other things, on powder extrusion. This involves extruding thermoplastic molding compounds with high proportions of metal or ceramic powders and then debinding and sintering them. The focus is on material development and adaptation along the entire process chain in order to achieve optimum results for the individual needs of our customers.

Shaping sintered materials by extrusion

In extrusion, materials are forced through a shaping nozzle in a viscous state under high pressure and temperature. This produces extrudates of any length, which have the same cross-section as the nozzle used. This means that even very complex structures can be produced. The subsequent debinding and sintering of the extrudates produces the finished components. By adjusting the process steps, such as changing the temperature, pressure or speed of the extruder, a wide variety of materials such as steels, copper and many other functional materials can be processed. This allows products to be manufactured for a wide range of industries such as automotive, aerospace, medical and energy technology.

In powder technology at Fraunhofer IFAM, we concentrate on the manufacture of metal and ceramic components by processing thermoplastic molding compounds with a high proportion of metal or ceramic powders. The focus is on material development and adaptation, in the context of which binder formulations and powder (the so-called feedstock) are precisely matched. Since processing has a significant influence on the subsequent material and component properties, density, hardness and other physical and functional properties can thus be adapted in a targeted manner to meet customer requirements.

Examples of materials and areas we process include:

Magnetocaloric materials

Here we look in particular at the shaping of fine structures for heat exchangers as well as thermal processing in order to optimally shape the form and function of these special materials.

Copper

The focus here is on components with high electrical and thermal conductivity. For high conductivity, it is important to obtain very pure materials, as all foreign substances have a disruptive effect.

Medical technology materials

Here, extrudates are of particular interest as semi-finished products if the materials are difficult to process in the sintered state. In this case, feedstocks must have high strengths in order to be reliably machinable even in the so-called green state.

Various extruders (single screw, twin screw) with data acquisition and a number of different test tools as well as haul-off devices for the extrudate strand are available for feasibility studies to produce smaller geometries while developing optimal feedstock and process parameters.