Three-dimensional extrusion on demand for metal partsThursday (08.10.2020) 11:10 - 11:30
The extrusion (plastic processing) is state of the art in the manufacturing of ceramic materials. The process was also successfully applied on metal materials and metal-ceramic composites via combination with powder metallurgical (PM) methods. Here, the powder raw materials are mixed with an aqueous organic binder system in order to form a plastic paste at ambient temperature. However, the geometry of the extrudate is limited since the pastes are pressed through a rigid die with constant cross section. So, each component to be manufactured demands a separate die. The production of dies for specific structures (e.g. honeycombs) is complex and expensive and the extrusion process cannot shape 3D-structures with varying cavities or undercuts without additional processing effort.
The new approach of three-dimensional (3D) extrusion on demand addresses these disadvantages. The plastic material is supplied from a separate extruder while the shape being manufactured is generated by a 3-axis machine with computerized numerical control (CNC). Providing the pastes continuously or non-continuously from the extruder enables the manufacturing of complex or hollow structures. The 3D-manufacturing of PM parts comprises the computer-aided design, the formulation of the plastic paste from the metal powder and an aqueous binder system, the 3D-shaping and the thermal treatment. Drying proceeds environmentally friendly due to the use of water as solvent and the organic binder can be removed by thermal debinding. The final consolidation during sintering in inert-gas atmosphere transfers the materials into their final state. The invented method enables future applications for other materials, such as metal-ceramic composites.