Fibre Manufacturing through Melt Extraction
In crucible melting extraction, a rotating, water-cooled copper wheel plunges into a melt pool. The wheel is wetted by the liquid metal which is sticking in a thread-like manner. Afterwards, the fibres are separating from the wheel by shrinkage and centrifugal forces. Making use of this method, at Fraunhofer IFAM Dresden, short fibres from 5 to 50 mm length and 50 to 200 µm thickness can be produced.
The melt extraction unit can be operated both under vacuum and inert gas. For that reason, metals and alloys can be processed to fibres at high purity. Enabled by the induction heating, melting temperatures of more than 2,000 °C are feasible. In connection with the induction field's moving effect, alloys whose density extremely varies of the individual components can be processed, too. Hereby, quick cooling by the water-cooled roller makes the structure very fine and homogeneous, which, in turn, positively influences on-going processing and the fibres' materials characteristics.