Technical Bulletin – Advanced Use of 3D-ADD CBA1 Bio
Thermally Activated Foaming for 3D Printing Resins
3D-ADD CBA1 Bio is a biocompatible chemical blowing agent paste designed to enable controlled post-print expansion in compatible photopolymer 3D printing resins.
The additive is mixed into the liquid resin before printing and remains inactive during printing and UV curing. Gas generation occurs only during a subsequent thermal activation step, enabling internal cellular expansion within the printed polymer matrix.
This two-step workflow allows users to explore lightweight structures, porous architectures and foam-like mechanical behaviour using standard SLA, DLP and LCD additive manufacturing systems.
How the System Works
During printing and UV curing the additive remains inactive and does not interfere with the photopolymerization process.
When the printed component is heated within a defined activation temperature window, the additive releases gas inside the polymer matrix. If the polymer network has sufficient mobility at that temperature, the gas pressure generates internal expansion and produces cellular structures.
The degree of expansion depends on several interacting variables including resin stiffness, crosslink density, additive loading, heating profile and part geometry.
Recommended Processing Workflow
1. Resin Preparation
- Typical loading range: 5–20 wt%
- Typical starting point: 5–10 wt%
- Lower loadings are recommended for initial printability screening and dimensional control
- Higher loadings may increase expansion potential but can also increase viscosity, light scattering and process sensitivity
- The paste format enables easy dosing and dispersion
- Mix gently to avoid air entrapment
- Typical mixing conditions: ~500 rpm for ~10 minutes
- For maximum suspension stability during long print jobs, optional addition of 3D-ADD ASC1 anti-sedimentation additive is recommended
2. 3D Printing
- Compatible with SLA, DLP and LCD technologies
- Moderate viscosity increase may occur depending on loading
- Minor reduction in optical clarity is expected
- Exposure settings may require adjustment due to increased optical scattering
3. UV Post-Curing
- Standard post-curing recommended
- Avoid excessive over-curing which may reduce expansion efficiency by increasing network stiffness
4. Thermal Foaming (Post-Processing)
- Heating method: convection oven, thermal chamber or controlled hot plate
- Recommended heating rate: 1–3 °C/min
- Activation temperature window: 140–180 °C
- Typical dwell time: 10–20 minutes depending on part thickness and geometry
Resin Compatibility
Flexible resins – Shore A 20–50 (Recommended)
- Polymer matrix softens sufficiently during activation
- Typical density reduction: 10–30%
- Produces soft foam-like internal structures
Semi-flexible resins – Shore A 60–90
- Reduced matrix mobility
- Expansion becomes localized
- Partial porosity achievable
Semi-rigid resins – Shore D 30–60
- Limited deformation during activation
- Expansion appears mainly as isolated voids
Rigid resins – Shore D > 60
- No effective expansion response
- Not recommended
Foaming Response vs Resin Modulus
| Resin modulus range | Typical foaming response | Expected structure | Recommended use |
|---|---|---|---|
| Low modulus (flexible elastomers) | High expansion capability | Open cellular foam-like structure | Soft-touch components, cushioning prototypes |
| Medium modulus (semi-flexible) | Moderate expansion | Mixed porous morphology | Lightweight flexible parts |
| High modulus (semi-rigid) | Limited expansion | Localized internal voids | Experimental lightweight structures |
| Very high modulus (rigid) | No practical expansion | Dense structure | Not recommended |
Foaming Window vs Polymer Network Rigidity
Conceptual engineering model describing the expansion behaviour of thermally activated foaming systems in photopolymer matrices.
The expansion behaviour of thermally activated foaming systems is governed primarily by the mechanical resistance of the cured polymer network during heating.
If the polymer network remains highly rigid during heating, gas generation cannot deform the structure and no expansion occurs. If the polymer matrix becomes sufficiently compliant, internal gas pressure can generate cellular expansion.
This behaviour defines a practical foaming window determined by the balance between gas generation and polymer matrix mobility.
| Polymer network condition during heating | Expansion behaviour | Resulting structure |
|---|---|---|
| Highly crosslinked / rigid network | Gas generation occurs but matrix cannot deform | No visible expansion |
| Moderately crosslinked network | Partial deformation possible | Localized internal voids |
| Flexible or elastomeric network | Matrix softens during heating allowing gas expansion | Cellular foam-like structure |
Programmable Density Photopolymers
By combining compatible photopolymer resins with 3D-ADD CBA1 Bio, users can explore a programmable density approach to additive manufacturing.
Instead of relying on a single material density, printed components may exhibit different density levels depending on additive loading, printing conditions and thermal activation parameters.
| Additive loading | Typical density behaviour |
|---|---|
| 0% | Solid printed structure |
| ~5% | Slight density reduction |
| ~10% | Moderate cellular expansion |
| ~15–20% | Maximum expansion potential |
Technical Note
The performance characteristics described in this document are based on typical processing conditions and internal testing performed under controlled laboratory environments.
The expansion behaviour of printed parts depends on multiple interacting variables including resin formulation, crosslink density, printing parameters, part geometry, thermal profile and processing equipment.
The specific formulation architecture and internal composition of the additive are proprietary.
Users are responsible for validating the suitability of the additive for their particular materials, equipment and applications through appropriate testing and process optimization.
3Dresyns Technical Positioning
3D-ADD CBA1 Bio is positioned as an accessible foaming additive for users exploring lightweight and porous structures in resin-based additive manufacturing.
For applications requiring tighter control of cell morphology, higher repeatability or industrial-grade foam performance, 3Dresyns provides advanced expansion technologies through its customized photopolymer material development programs.