Introduction
Material extrusion is an additive manufacturing technique that uses a continuous filament of thermoplastic or composite material to construct 3D parts. Filament-based material extrusion is the most common practice in the 3D printing community. However, it’s not necessary for extrusion to only work with filament. In fact, pellet extrusion is a stable process that offers more flexibility and choice in 3D printable materials. With pellet extrusion, a screw is used as a feeding mechanism to move and melt the material inside the barrel, before forcing it out of a heated die. REGEMAT 3D offers researchers highly customizable modular 3D bioprinting systems with independent movements in Z axis. Researchers can select the configuration of the printing system according to the needs of the research: top choices include extrusion-based modules compatible with: 1) syringes for the extrusion of hydrogels and thermoplastic biomaterials in 2) filament and 3) pellet format. By installing a pellet extruder instead of filament extruder usually reduces the cost of printing process since materials in pellet format are usually cheaper. The following protocol describes a method for generating poly(L-lactide) (PLLA) scaffolds with high resolution through pellet extrusion.
Materials
- Poly(L-lactide) PLLA in pellet format
Equipment required
- REG4Life bioprinter with pellet extruder
- PC with REGEMAT 3D Designer software
Methods
- Turn on the REG4Life bioprinter, connect it to the PC and launch REGEMAT 3D Designer software. Click “Connect” button.
- Select “Pellet extruder” in the header configuration and proceed with its calibration.
- Load the biomaterial (in this case, PLLA) in the pellet extruder collector.
- Heat the nozzle at the melting temperature of the material specified by the supplier (in this case, 230°C).
- Load the .stl file with the 3D design of the desired 3D structure to print, select object and extra configurations and proceed to print on the glass bed.
Example of object configuration:
|
Scaffold |
Cylinder |
|
Layer height (mm) |
0.25 |
|
Total layers |
8 |
|
Size (mm) |
2 x 20 (h x diameter) |
|
Pore size (mm) |
1 x 1 |
|
Infill pattern |
Diagonal, with 90º angle |
|
Solid layers |
First layer |
| Printing temperature (ºC) |
230 |
- Materials with low adhesion may require to switch off the layer fan.
Photographs of pellet extruder collector (up, left), extrusion of the filament (down, left) and printed structure (right)
| Number | Category | Product | Amount |
|---|---|---|---|
| 1 | - | PLLA pellets | 1 |