In this laboratory it is possible to undertake all the necessary steps to model and then create your own three-dimensional prototype. It is a laboratory at the service of those who need it; therefore, the applications of the created prototypes can be the most varied. Ranging from customized supports for optical fibers (probes) and optical components, for phantom, etc. Customization is guaranteed by the presence of 3D printers and the required software for rendering and printing (Activity Prototyping and 3D printing). Furthermore, the interactions of new materials for 3D printing with light are studied in the context of the diffusion theory (Activity Study of the interaction between light and materials for 3D printing).

Prototyping and 3D printing

In addition to several 3D printers, the laboratory also owns a PC equipped with professional software, necessary for the creation of the three-dimensional models of the desired objects and for the creation of the files suitable for the 3D printing settings (Rhinoceros, Simplify3D, as well as other free software downloadable from the web).
It is then possible to proceed with the prototyping of the object and then its printing with one of the available 3D printers (i.e. filament or resin printers).
There is a wide range of different filaments available, in terms of materials, colors and mechanical characteristics (PLA; FLEXIBLE, etc.).
The molded parts can be post-treated from a mechanical point of view. Typical treatments are, for example, the finishing of the holes, the insertion of mechanical parts, screws and more. These mechanical processing are possible thanks to the presence of specific tools.
In the figure, there is an example of a piece entirely thought, designed, printed and post-processed in the laboratory. It is a probe for non-invasive fNIRS optical spectroscopy measurements on the brain of a volunteer. It is made of non-flexible PLA, but its engineering has allowed to make it slightly flexible, in order to better adapt to the head curvature. The optical fibers that emit and receive light are inserted into the holes and fixed.

Study of the interaction between light and materials for 3D printing

The use of 3D printed materials, such as PLA or ABS, for the employment in objects (probes, phantom caps, etc.) designed for applications within diffusive optics (fNIRS, DCS, RAMAN, ...) led to the need to study the applicability of these materials in this specific sector.
They had been extensively studied from a mechanical and chemical point of view, but not so much can be yet found in literature, regarding their optical applications (only some information in the UV field). Therefore, we began to study them in a more concrete way, discovering particular characteristics from the optical point of view (Amendola et al).
For example, some black PLA filaments (as shown in the photo and the transmittance spectrum in the figure), are actually transparent to red and infrared radiation, a feature that is not compatible with their employment in single photon spectroscopy techniques.
The laboratory is active in their continuous characterization, and it is moving towards the direction of studying their optical properties in terms of scattering and absorption coefficients.

Equipment

• 2 filament 3D printers with double extruder and heated bed (Sharebot NG);
• 1 filament 3D printer DELTA (3D Delta WASP 2040);
• 1 filament 3D printer PRUSA (i3 MK3S+);
• 1 filament 3D printer (Geeetech I3 X PRO);
• 1 filament 3D printer (Geeetech A20M);
• 1 resin 3D Printer (Elegoo Saturn 4K);
• 1 wash and cure machine (ANYCUBIC Wash and cure 2.0, 2 in 1).