The project is focused on the production of the 3D components by means of the extrusion-based 3D-printing process “Fused Deposition Modeling (FDM)” with short and continuous-fiber filaments on the basis of natural fibers. The utilization of this technology in architecture is targeted at two different application purposes:
1. Simplified production of established components
The objective is for established architectural components – which, up until now, have required many manufacturing steps – to be produced using faster, simpler and more adaptable manufacturing processes. The focus thereby lies on components which, due to their design or function, exhibit a high degree of individualization and complexity - for example, façade elements, free-form furniture items and partition walls as well as multifunctional components.
2. Novel, highly efficient building components
A further objective is the development of completely new types of architectural components which cannot be produced by means of conventional manufacturing processes. One conceivable example would be a load-bearing ceiling element whose topology is adapted to the static load. This would allow slender ceiling structures with minimal material requirements.
In both cases, the components should be made as extensively as possible from renewable raw materials.
The primary task of the Fraunhofer WKI is the development of the bio-based filaments for the production of components for interior construction and façade elements using the FDM process. A particular challenge hereby is the production of uniform and spoolable filaments that can be easily extruded.
Short-fiber filaments
The matrix polymers to be used include polylactic acid (PLA) and biopolyamides. By means of compounding, we reinforce the polymers with regionally available wood fibers and cellulose fibers. These should improve the thermal dimensional stability of PLA and reduce shrinkage of the components.
Continuous-fiber filaments
The continuous fibers (natural fibers) should enable the production of structurally more durable components. We are developing a process for the coating of regionally available flax and hemp fibers with thermoplastic biopolymers.
Multi-material 3D printing
We optimize short-fiber and long-fiber-reinforced filaments with respect to processing in multi-material 3D printing. As a result, the specific advantages of the different materials can be combined in a targeted manner within a single component.
Additivation
Components are subject to high requirements such as durability, UV stability and flame retardancy. In order to achieve these, we equip the biopolymers with suitable additives.
Evaluation and characteristics
The printed samples are evaluated in terms of their uniformity and we determine their properties (mechanics, flame retardancy, etc.).
Fraunhofer Institute for Wood Research 
