RepRapMicron Benchy: Microscale 3D Printing with Optical Fibre
Summary: The RepRapMicron project demonstrates microscale additive manufacturing by printing a 1/100th scale 3DBenchy measuring just 650μm in length. By coupling an optical fibre with a manual UV light source and nail art resin, this setup showcases an accessible path toward extreme high-resolution fabrication.
Key Takeaways
- Extreme Scale Reduction: The 3DBenchy was scaled down to 1/100th of its standard size (650μm long) and sliced at 2μm layer heights using PrusaSlicer.
- Fibre-Delivered Photopolymerization: UV light is routed through a 125/9 optical fibre positioned directly over a glass slide inside a droplet of nail art resin.
- Hardware & Software Integration: Movement is driven via GRBL controlled by CNCjs, relying on microscope cameras for physical zeroing and visual inspection.
Detailed Overview
Miniaturizing the iconic 3DBenchy benchmark is a classic test for additive manufacturing processes, but producing one under a millimeter pushes standard motion systems and resins to their limits.
The print was sliced using PrusaSlicer, with the output G-code manually filtered to strip out standard extrusion commands and extraneous syntax that could disrupt GRBL. The model geometry was brought down to 650μm in length.
Setup and Calibration
The machine workflow was monitored and driven using CNCjs in conjunction with live microscope views to coordinate positioning:
- Touch-off Calibration: The tip of a 125/9 optical fibre was carefully lowered onto a glass slide by eye using video magnification.
- Z-Offset: The tip was raised approximately 30μm from the surface to establish the baseline print height.
- Resin Application: A single droplet of commercial nail art resin was applied directly onto the fibre tip.
Deep Dive & Technical Insights
Print Execution Parameters
| Parameter | Value |
|---|---|
| Model Length | 650 μm (1/100th scale) |
| Layer Height | 2 μm |
| Print Speed | 10 μm/s |
| Total Print Duration | ~13 hours |
| Fibre Type | 125/9 optical fibre |
| Resin Material | Nail art UV resin |
Because non-printing travel speeds were vastly higher than the 10μm/s printing speed, the UV source did not require continuous pulsing or synchronization between individual travel moves.
Observed Challenges and Future Optimizations
- UV Control Integration: In this run, the UV source was operated manually. Because the print finish was missed by five minutes, the part received slight overexposure. Automating UV switching directly through GRBL commands will prevent excess curing.
- Z-Axis Light Bleed: The optical UV radiation penetrates through cured layers, polymerizing unintentional resin below the model. Potential solutions include introducing UV absorbers such as turmeric extract (as used by Diffraction Limited) or UV-blocking marker inks.
- Speed & Layer Scaling: Increasing layer thickness slightly and pairing an upgraded UV source with faster feedrates will drastically reduce the 13-hour print time.
Conclusion & Resources
The initial RepRapMicron Benchy run proves that fibre-delivered photopolymerization is an accessible and viable technique for microscale stereolithography. Even with manual UV control and off-the-shelf nail resin, functional sub-millimeter parts are well within reach.
- Follow-up Results: Check out subsequent refinements in the RepRapMicron Success Post.
- Project Background: Visit the RepRap Project for history, documentation, and open-source development updates.