Projet cjp 660pro

Prototypes of the standard and the ENT face shields were test-fitted on three 3D-printed headforms (Fig. 3) representing the small, medium and large head size categories of the population [15 (link)]. These International Organization for Standardization (ISO) Digital Headforms were specified in ISO 16976–2 [16 ] and were 3D-printed on a ProJet CJP 660Pro (3D Systems, Rock Hill, South Carolina, USA). The strap-length was adjusted so that the fit was acceptable on each ISO Digital Headforms, ensuring that a single strap-length would be acceptable to wearers with different head-shapes.Fig. 3

3D printed ISO headforms mounted with face shields. The small (left, with an ENT face shield), medium (middle) and large (right, with a standard face shield) headforms are representative of the head size groups of the population, and were used to gauge the length of face shield strap required to accommodate the range in head sizes.

Fig. 3

Printing was conducted using a binder jet 3D Printer (Projet CJP 660 Pro, 3D systems, USA). As shown in Fig. 2, the designed model file was uploaded to the software of the 3D printer, which sliced the model and sent the slices to the 3D printer. Thin layers of powder mixture (100 µm per layer) were spread across the platform. The print carriage moved across each layer, using 5 hot-bubble printing heads (HP11, Japan) to selectively deposit clear or colored printing inks of specific composition, which were loaded into a cartridge through a 10 µm filter. Each printing head has 304 nozzles, and a single droplet from the nozzle is 18 pl. The ink solidified the powder only in the cross-section of the designed model, and the remaining powder was used for support. The print resolution was 600 × 540 Dots Per Inch (DPI), and the maximum vertical build speed was 28 mm per hour. After printing, the tablets were dried at 40 °C for at least 1.5 h to remove organic solvent and excess moisture, and the support powder was recycled for reuse through an integrated vacuum system. The tablets were then cleaned with an air brush to remove excess powder.Fig. 2

Schematic diagram of the printing process of colorful cartoon tablets using a binder jet 3D Printer.

Fig 2