Fused Feedstock Deposition (FFD)
3D Printing Ceramics
3D printing of individual components with the perfectly fitting ceramic
With the Fused Feedstock Deposition we can offer you the production of individual component geometries from a variety of commercially available ceramic materials. With our know-how in the field of feedstock development of various materials in the field of vacuum hot casting, we can offer you, within the scope of a feasibility study, an additional material development, in which the feedstock can be adapted exactly to your needs.
In Fused Feedstock Deposition (FFD), a ceramic feedstock in the initial form of a granulate is melted and selectively applied to a building platform using a 3D printing process. The basic process is very similar to Fused Deposition Modeling (FDM). The difference between the two processes lies in the materials processed. FDM uses mainly thermoplastics, whereas FFD uses thermoplastics and kerosenes to produce extrudable ceramic and/or metal feedstocks that can be processed using 3D printing.
How does Fused Feedstock Deposition work in detail?
As with any other 3D printing process, the process begins with the design of a CAD file. This CAD file is then broken down by software (Slic3r Prusa Edition) into horizontal layers (slices), the height of a layer being determined by the selected layer thickness. The layer thickness again depends on the nozzle diameter used. Normally, the layer thickness is always selected slightly smaller than the nozzle diameter in order to ensure complete adhesion between the individual layers during printing. In addition, the software translates the individual travel paths of the print head of each layer into a language (G-Code) that is understandable for the FFD machine. In addition to the movements of the print head, the print script also controls other print-specific parameters, such as the material flow or the print head speed during the printing process.
The material used is usually commercial feedstocks in the form of granules from ceramic injection molding. The granulate is drawn from a reservoir into a screw extruder during printing. There it is conveyed and heated to processing temperature by means of a heating element, which melts it. Due to the constant feeding of the feedstock in the screw extruder, the melted material is extruded through a nozzle at the end of the extruder, allowing a continuous strand to be deposited on the building platform. This strand is then used to build up a pressure layer of the component to be produced by means of the travel paths previously generated in G-code. The deposited strands of a layer solidify and harden again by cooling on the building platform, so that a further layer can be applied. To apply the next layer, the Z-axis is then moved upwards. Depending on the model, either by lifting the print head or by lowering the building platform. Now the next layer is applied, with the parameters previously defined by software, and so on, until the entire component has been built up. Before the component can be sintered, it must be debindered in order to partially dissolve the thermoplastic organic material, which can otherwise lead to distortion or even cracking in the component during firing. After sintering, the component then has the appropriate material properties for the application.
What are the possibilities of Fused Feedstock Deposition?
In principle, the FFD process is a relatively inexpensive process, which is particularly suitable for prototype development and individual production due to its high flexibility. Due to the relatively high process speed, however, small series productions are also conceivable. Components manufactured with the FFD process are usually characterized by low porosity and high strength. The desired quality can be flexibly adapted to the corresponding requirements by selecting different nozzle inner diameters (0.4 – 1.5 mm). In contrast to Fused Deposition Modelling (FDM), FFD does not require the sophisticated production of a reliable filament, as mixtures of thermoplastics and ceramic powder are used as finished granulate. Since these granules are usually produced on a large scale for ceramic injection molding, they are commercially available. Thus, a wide variety of ceramic, metallic, but also polymer feedstocks can be used, and this at manageable costs.
What are the limitations of Fused Feedstock Deposition?
With our printing system “FFD 150H” of the company 3d-figo the maximum component size is 150x150x150 mm. The wall thickness of the component should not be less than 1 mm and not exceed 5 mm. Overhanging structures above approx. 45°C must be provided with supporting structures. The resolution possibilities as well as the surface finish, however, cannot keep up with the precision of Binder-Jettings. In contrast to cold plastic extrusion, FFD has an additional debinding step. Due to the wide range of commercial feedstocks, costs in the area of material development can be saved.