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International Journal of Bioprinting 3D-printed hydrogel with antioxidant activity

Figure 4. Printability of the ink depending on printing conditions: (A) width, length, height, and volume of the constructs, (B) thickness expansion, and
(C) dimensional error.

Appropriate extrusion can be accomplished by Since smaller dimensions of the printed constructs having
controlling printing speed and nozzle diameter. At fixed larger specific surface area might be beneficial for different
conditions of 50% infill density, 0.8 mm nozzle diameter, applications, this limitation should be overcome in a
and 0.4-mm layer height, the dimensional error of the future study.
construct reduced with increasing printing speed. This Layer height affects the theoretical number of layers.
might be attributed to the short residence time of the ink A better printability in terms of thickness expansion was
in the nozzle at higher speed. The nozzle diameter can obtained when a layer height of 0.3–0.5 mm was used, as
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also affect manufacturing times and product quality. Also, compared with 0.6 mm, showing a reduction of thickness
in general, a larger diameter is preferred to enhance the expansion by 1.25 folds. This is in line with the general
final quality of the printed constructs with high density. concept that the recommended layer height should be 0.5
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In this study, a diameter of over 0.8 mm resulted in < 7.5% times the nozzle diameter. It might be because the larger
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dimensional errors. Only at a 0.4 mm diameter (i.e., the distance between the nozzle tip and the top of the product
smallest one), a significant difference was observed; this layer produces low-density constructs. Consequently,
was probably because of the formation of non-interacting layer heights of both 0.4 mm and 0.5 mm were suitable
infills following the reduced pressure between the ink for 3D printing using CMFs. In this study, the optimal
and the nozzle wall, resulting in weak horizontal bonds. infill density, printing speed, nozzle diameter, and layer
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Volume 10 Issue 1 (2024) 250 https://doi.org/10.36922/ijb.0164