Extruder for 3D-printing cellulose based materials
TEAM : Ville Klar, Pyry Kärki, Petri Kuosmanen (Aalto University), Hannes Orelma, Tiia-Maria Tenhunen (VTT)
A 3D-printer prototype was developed to explore various cellulosic materials in additive manufacturing. Various paste extruders were developed, tested and compared to commercially available paste extruders. A closed-loop control syringe pump design was shown to be most functional and was used to print various cellulose solutions and suspensions.
The extruder has accurate sensors for both linear movement and piston pressure. Different control algorithms can be efficiently tested with the developed software tools. The extruder can be operated in a speed or pressure mode which enables accurate dosing of liquids with different flow behaviors. An open-source software tool chain was used to make the digital manufacturing process both efficient and versatile.
The extruder has been used to successfully print for example cellulose solutions, cellulose acetate and cellulose acetate butyrate solutions as well as different aqueous nanocellulose suspensions in different dry matter consistencies. The structure of the 3D printer enables facile printing on different substrates such as fabrics.
Most publications related to e.g. printing of nanocellulose are focused on biomedical applications such as wound dressings and scaffold raw material for cartilage tissue engineering. Optimizing the printing process to achieve both good control of the geometry and high mechanical properties would broaden the application range to e.g. packaging and architecture.