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International Journal of Bioprinting Vector-based G-code generation for biofabrication

circular pattern was printed with the infill direction shifted sequenced to create the desired machine instructions. This
by 45° for each layer. method makes the creation of new patterns and codes
intuitive, allowing for easy manipulation and visualization
Additionally, to showcase the advantage of free infill
control, a cube was printed with the infill orientation of shapes directly within the drawing software. It also
consistently at a 90° angle to the edge, as shown in enables rapid prototyping and quick adaptations of designs,
Figure 6B. This would be challenging to achieve using a making it especially useful for those less experienced in
conventional FDM slicer. More complex shapes, such as an writing G-code or working with parametric programming.
ear in Figure 6C, can also be generated. The key advantage The real advantage of this method becomes apparent
is the ability to freely determine the paths and transitions when working with complex geometries or non-repetitive
between layers, reducing unnecessary extrusion stops, and structures. The combination of intuitive path drawing and
improving overall pathfinding. For easier conversion of a real-time visualization provides a level of flexibility and
3D object into a layer-by-layer approach, an FDM slicer ease of use that parametric programming cannot offer.
can be used to generate each sliced layer, which then serves Additionally, because most of the generated code consists
as a backbone for drawing the desired print paths. of relative G1 movements, it is easy to adapt the code
for use on different machines, even those with varying
3.4.3. Embedded bioprinting software or G-code flavors. This enhances the horizontal
Embedded bioprinting was employed to print more intricate
shapes without the need for supports. The flexibility in the transfer of code between different devices, making the
Z direction was demonstrated through the creation of a method versatile for a wide range of applications.
meandering pattern, as shown in Figure 6D. Additionally, a Furthermore, the vector-based approach significantly
layer-by-layer 3D heart structure was successfully printed streamlines the integration of multiple fabrication
using this coding approach, as depicted in Figure 6E. The methods. When combining different processes, such as
method also facilitates precise multimaterial printing, laser cutting and FDM, alignment and scaling can be a
making the creation of multimaterial objects relatively challenge if generated by separate software. However, by
straightforward, such as the 3D institute logo printed in using the drawing method, paths for different processes
two colors, as shown in Figure 6F. Furthermore, by using can be drawn in the same file, ensuring that they are
3D design software like Blender, more complex shapes and scaled and fit together seamlessly. This facilitates the
paths that are not feasible to create with a traditional layer- integration of multiple machines and technologies into a
by-layer approach can be designed. These 3D paths can cohesive automated workflow, improving both the speed
then be integrated with the Adobe Illustrator-generated and reliability of biofabrication processes. It eliminates the
paths when compiling the G-code, effectively merging need to adapt proprietary slicers for FDM to bioprinting
the two approaches and providing a unified, flexible needs, allowing users to rapidly generate print codes and
visualization of the final design. maintain full control over the printing paths. The method
supports the production of complex 3D objects with
5. Conclusion precise spatiotemporal control over the printing sequence,
Automation in biofabrication is crucial for improving material deposition, and infill patterns. This capability
reproducibility and yield in the production of biologically is crucial for biofabrication, especially in aligning cells
relevant substrates. A key element of this automation is with the print path direction, as when using fibrous filler
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the ability to efficiently control and program the machines materials. Such fibrous particles can align as they flow
involved. Since many biofabrication devices operate with through the nozzle, forming anisotropic internal structures
three degrees of freedom or Cartesian architecture, 37,38 that impart biomimetic, direction-dependent properties. It
G-code is typically used for machine control. However, also allows for the fabrication of complex, geometrically
generating G-code can be cumbersome, especially for irregular organic structures, which is critical for replicating
those without expertise in parametric programming or the intricate geometry of biological tissues. These features
manual coordinate input. ensure the production of functional, mechanically
appropriate structures for biomedical applications.
To address this, we developed a straightforward, user-
friendly G-code generation method that is adaptable to Thus, this drawing-based G-code generation method
most biofabrication machines. By leveraging vector-based offers an efficient, intuitive solution for biofabrication,
illustration programs like Adobe Illustrator, users can draw making complex shapes and multimaterial printing more
and segment paths into linear subroutines, which are then accessible while providing robust flexibility for adapting to
exported as relative G-code blocks. These blocks are easily different machines and fabrication techniques.

Volume 11 Issue 4 (2024) 221 doi: 10.36922/ijb.6239