In this research, the material development of a continuous wood filament out of solid willow withes and related novel digital fabrication processes are investigated. The project is part of an interdisciplinary research group consisting of six professorships in the fields of architecture, arts, fabrication technology, simulation technology, wood structures and material science at the University of Kassel. Part of the project is the development of additive robotic fabrication processes similar to automated fiber placement and robotic filament winding.

During the development of the timber fiber placement process, there were several other challenges compared to common 3D printing methods. Using continuous fibers in an additive manufacturing process required the material to be cut and reapplied during the process, and the adhesive system required contact and pressure within a limited time span. We developed a custom robot end-effector to achieve specific extrusion, adhesive application, pressurized application and cutting procedures. In addition, a robotic winding process for the solid-wood monofilament was developed by extending the robotic setup with an external rotation axis.

Besides the fabrication process, we developed a computational design model based on topology optimization. In this model, one-dimensional finite elements are used that represent the solid wood filaments. With the developed filtering approach, we can influence the appearance of the optimized design and control the minimum length of the placed filament.

Several student projects were related to this research project. The results of these student projects are presented in the videos below.