Many of these devices require some attention when printing. Because 3D printers fabricate objects from thin layers of plastic, there is a grain to the structure of the printed parts, much like there is grain in wood. Many of the parts used in the e-NABLE hands need to be printed in a particular orientation so that the “grain” of the print is oriented to maximize the strength of the part.
For instance, most gauntlet designs need to be printed with the two arms in contact with the build platform. While this does require some amount of support material, it aligns the layers of the print with the directions of loading during use.
Materials are still an area of active exploration. e-NABLE members are currently fabricating hands using ABS, PLA, and Nylon, each of which has specific printing requirements.
Branebot put together a great Instructable describing the process of printing a Cyborg Beast in Nylon and dying it.
Recommendations for PLA:
- Extruder: 180-230C (depends heavily on type of machine)
- Bed: 0-60C
Recommendations for ABS:
- Extruder: 230-240C (depends heavily on type of machine)
- Bed: 80-110C
Recommendations for Nylon:
- Extruder: 240C
- Bed: 80C (PVA/Elmer’s glue stick helps with adhesion)
- Retraction: 4mm or greater (based on MendelMax running Repetier firmware and
- Nylon filament must be kept desiccated when not in use.
Dimensional accuracy is very important for these hands as there are a lot of moving parts that need to fit together precisely and with minimal play. The following resources can guide you through the calibration process for most desktop 3D printers:
- Solidoodle calibration guide on Instructables
- RichRap’s RepRap calibration guide: Slic3r and extruder
- RichRap’s Slic3r calibration guide: filament and printing
e-NABLE Quality Specification
In order to maintain quality prints across many different types of printers, we ask for volunteer fabricators to target the following quality specification:
- No large gaps in between shells. The print must be “water-tight”.
- Layer height between 0.1mm and 0.25mm.
- No experimental, scented, or chemically-treated filament.
- Parts must be fabricated according to the above orientation guidelines.
- Printer must be properly calibrated to achieve the dimensional tolerances necessary for functioning hands.