Applied Engineering Analysis - Fine Tuner FT1 & LB1 Bio (385 & 405 nm)
Material system: 3Dresyn PEEK-like with Fine Tuner FT1 (photo-accelerant) and Fine Tuner LB1 Bio (resolution modifier).
Optical conditions evaluated: 405 nm; 2.2 / 4 / 6 / 8 mW/cm2.
Methodology: Cure depth mapping, dose reciprocity analysis and Jacobs working curve modelling.
Why This Matters
In practical SLA, DLP and LCD printing, performance is defined by two competing goals:
- Printing speed
- Dimensional accuracy (XY and Z)
Fine Tuner FT1 and Fine Tuner LB1 Bio allow controlled adjustment of these two variables — but they influence the system differently.
Engineering Framework
The system is described by the Jacobs equation:
Cd = Dp · ln(E / Ec)
- Ec (mJ/cm2) → Cure onset sensitivity (kinetic threshold)
- Dp (µm) → Optical penetration depth (confinement control)
Measured Behaviour (405 nm)
| Formulation | Ec (mJ/cm2) | Dp (µm) | Engineering Interpretation |
|---|---|---|---|
| 2% FT1 + 5% LB1 Bio | 23.23 | 184.20 | Balanced baseline |
| 4% FT1 + 5% LB1 Bio | 19.96 | 190.21 | Higher speed potential |
| 2% FT1 + 10% LB1 Bio | 19.09 | 148.25 | Higher dimensional confinement |
Effect of Increasing FT1 (Speed Control)
Increasing FT1 reduces Ec. This means the resin begins curing at lower dose, enabling shorter exposure times per layer.
Result: Increased effective printing speed.
However, Dp increases slightly. If exposure is not reduced accordingly, the system may:
- Increase cure depth beyond target
- Increase interlayer overlap
- Reduce Z-detail fidelity
Engineering guidance: When increasing FT1, reduce exposure time proportionally to preserve dimensional stability.
Effect of Increasing LB1 Bio (Resolution & Confinement Control)
Increasing LB1 Bio significantly reduces Dp (penetration depth).
Result:
- Improved vertical confinement (Z-direction)
- Reduced cure-through between layers
- Improved edge definition
- Better small-feature retention
This improves dimensional accuracy in both XY and Z directions.
However, stronger confinement reduces the process margin. Adequate dose must still be delivered to maintain interlayer adhesion.
Engineering guidance: When increasing LB1 Bio, maintain minimum dose above the adhesion threshold while avoiding overexposure.
Dimensional Accuracy — Practical Interpretation
Z-Direction (Layer Thickness & Vertical Geometry)
- Dominated by Dp and delivered dose.
- Lower Dp → improved Z fidelity.
- Higher Dp → increased risk of vertical overgrowth.
XY-Direction (Feature Width & Edge Definition)
- Dominated by optical bleeding and cure kinetics.
- Higher LB1 Bio → reduced lateral bleed → improved XY precision.
- Higher FT1 requires exposure optimisation to avoid swelling.
Dose Control — Critical for Reproducibility
Dose (mJ/cm2) = irradiance (mW/cm2) × exposure time (s)
Two printers using the same time per layer can deliver different cure behaviour if irradiance differs. For reproducibility and technical support purposes, irradiance at 405 nm should be measured and reported.
Application-Oriented Recommendations
If Your Priority Is Maximum Speed
- Increase FT1 (e.g., 4%)
- Reduce exposure time accordingly
- Validate Z fidelity with calibration geometry
If Your Priority Is Maximum Dimensional Accuracy
- Increase LB1 Bio (e.g., 10%)
- Maintain adequate minimum dose for adhesion
- Validate XY and Z features using structured test files
If You Need a Balanced Industrial Workflow
- 2% FT1 + 5% LB1 Bio provides stable processing margin
- Suitable for general-purpose production environments
Validation Protocol
Dimensional performance should be validated using:
- 3Dresyns calibration files
- 3Dtest1 (XY feature fidelity)
- 3Dtest2 (Z-step and thin wall confinement)
All reports should include irradiance (mW/cm2), layer thickness, and post-processing conditions.
Strategic Conclusion
FT1 controls speed.
LB1 Bio controls precision.
Dose control aligns both.
Optimal industrial performance is achieved by balancing kinetic acceleration and optical confinement, validated through structured calibration and measured irradiance.
Technical support: info@3dresyns.com
Underlying Cure Kinetics Data
This applied engineering interpretation is supported by full cure depth modelling and Jacobs working curve extraction available here: