Additive manufacturing (AM) (AIMEN, ES)

PL15 covers the value chain from product engineering to the final product manufacturing related to two 3D printing technologies for bio-based materials processing: Large Format Additive Manufactiring (LFAM) for thermoplastic TPU (LIST, UEdin) polymeric composites and Photopolymerization (SPP & MPP) for bio-based resins (FH-WKI).

The filament production station and LFAM cell includes a Robot Printing Arm R-2000iC/125L that has been purchased from FANUC and a new extruder (CEAD’S pellet based robot extruder) altogether with CEAD’s large heated printed (3x1.2m) table that enables large format robotized additive manufacturing technology, allowing to process virtually any thermoplastic polymer suitable for 3D printing. To complete PL15 upgrading a Filament Extruder Station and a pelletizer (showed in Fig 1c and 1d) purchased from Machine AB KFM Sweden has been as well incorporated. Pelletised material obtained from the extruder station can already be directly 3D printed using the LFAM cell robot extruder avoiding the filament winding step.

pilot lines templates image
pilot lines templates image

The 2 Photon Polymerization station has been equipped with the new resin dispenser, with a maximum printing area of 14.5×14.5 cm×cm. The maximum printing height is theoretically limited by the maximum excursion of the current Z axis (25 cm) where a commercial fabrication platform from Formlabs has been installed. A large distance microscope objective (Olympus LMPLFLN50X) with a 50× magnification and 0.5NA focuses the 515 nm fs pulsed laser (EKSPLA Femtolux 3) inside the resist for its selective curing layer by layer. The motion of the laser beam for each layer is driven by two linear axes from PI (LS-110), while the activation of the laser is controlled by the gate signal which is in turn activated by the motion controller from PI (MPA-DMC). A CCD camera from Thorlabs (CS165MU) was used to check the focusing position on the fabrication platform. The fabrication process is completely programmed in Python, including some libraries for autofocusing purposes. Further developments will include the CAD files into fabrication trajectories than will be used for the fabrication of the final 3D samples. The upgrade of this machine will be completed in the following months with the installation of a set of linear axes with a higher positioning precision and a microscope objective piezo stage with a fast response to improve the autofocusing procedure.

This preliminary configuration has been already used to test the printability of the resins provided by the Fraunhofer WKI. Two different sets of structures: blade-like and rectangular cuboids were fabricated to test the minimum resolution that could be achieved with this configuration, which was within the micron range.