Select your 3D resin by Shore hardness, Young’s modulus and real structural behaviour
SSF integrates three complementary engineering pillars:
- Engineering Selection: geometry-driven stiffness logic (E × t³) (shown below in this document)
- CRT: exposure–cure depth calibration: The 3Dresyns® Curing Rate Control System
- SMSP: empirical mechanical fingerprinting 3Dresyns®: 3Dresyns® Structured Mechanical Screening Protocol (SMSP)
This tool helps you estimate how material stiffness (Young’s modulus) and part geometry interact to determine the perceived flexibility of a printed component. The calculator provides a first-order engineering comparison that helps identify whether a geometry will feel flexible or stiff before printing.
- Step 1: Start from the Shore hardness range or target tactile feel.
- Step 2: Use wall thickness and span to estimate how much the part bends.
- Step 3: Select the resin that meets your stiffness target while also satisfying toughness and strength requirements.
This calculator is intended for first-order comparative screening. It uses a simplified beam-deflection model to compare relative stiffness between material and geometry combinations.
It is not a structural simulation and should not replace engineering validation, testing or finite element analysis (FEA) for final part design.
For beam-like structures, bending stiffness scales approximately with E × t³, where E is Young’s modulus and t is thickness. This means that doubling thickness increases stiffness by roughly eight times. In many cases, geometry has a stronger influence on perceived stiffness than the material itself.
In real use, a finger applies force over an area, not at an ideal mathematical point. This tool uses a simplified beam-bending model so thickness and materials can be compared consistently. It is intended for first-order screening, not for full FEA or final design validation. If the tool predicts bending larger than the span length, the chosen inputs are not representative for a realistic “feel” check.
Thickness presets (tmin)
tmin represents the smallest wall or feature thickness present in the region of interest. This value is often used as a conservative reference for stiffness estimation because the thinnest section usually controls the bending behaviour.
Use-case presets
Click one preset to start with realistic values, then refine the inputs to better match your geometry.
Finger press intensity
These buttons set realistic starting values for a normal wall thickness. You can still edit the inputs afterwards.
Inputs
Typical finger press forces in product interaction are often in the range of ~1–5 N, depending on part size and user interaction.
Fine detail walls are often ~0.05–0.20 mm, general thin features ~0.3–0.8 mm, and structural walls or panels ~0.8–2.0 mm.
Outputs (live)
E × t³ is a quick stiffness indicator combining material and geometry. For similar spans and loads, a higher value usually means a stiffer response.
Thickness vs modulus chart
This curve shows how the required thickness (t_required) varies with Young’s modulus for the selected load and geometry. It helps visualize how geometry can compensate for material stiffness differences.
- Early-stage resin selection before printing
- Comparing stiffness trends between resin families
- Screening thin walls, clips, panels and delicate features
- Identifying which candidates should be validated with CRT and SMSP
- Final structural validation of the printed part
- Finite element analysis (FEA)
- Application-specific testing under real service conditions
- Exposure calibration and curing-depth characterization
Once a suitable stiffness range is identified, the next step is to validate curing behaviour and printed performance using:
The calculator is based on a simplified beam-bending model used for first-order screening. Real printed components may deviate due to anisotropy, boundary conditions, support structures, print orientation and post-curing conditions. Final designs should be validated experimentally.