When to pick this combination
Pick FFF ULTEM 9085 when the part needs FAR 25.853 flame-smoke-toxicity compliance in a polymer, prints on a Stratasys F900 / Fortus class machine, and the geometry is small-feature-tolerant. Standard for cabin interior ducting, brackets, and grills.
- Cabin interior ducting and grills
- Aircraft brackets within FAR 25.853 compliance
- Low-pressure manifolds in PEI-acceptable service
- Tooling masters for layup
Typical defects and how the model accounts for them
FFF anisotropy is severe: Z-direction strength runs 35–55% of X-Y. Print orientation is the single biggest lever. ForgeCast aligns the dominant principal-stress axis with X-Y by default and surfaces a warning if geometry forces Z-aligned load.
Required post-processing
The allowables above assume the full post-processing chain. Skipping any step degrades the row by 15–35 %.
- Anneal: 160 °C / 4 h (recovers ~10% strength)
- Support removal: soluble or break-away
- Surface: as-built layer lines visible; vapour-smoothing not standard for PEI
- Verify FAR 25.853 per material lot
Suggested build parameters
Starting recipe; tune against first-article inspection on geometry-sensitive features.
- Layer: 0.18 mm typical
- Nozzle: 0.4 mm
- Bed: 195 °C
- Chamber: 175 °C
Frequently asked questions
Can FFF ULTEM 9085 carry primary structure?
No. Its layer-bonding anisotropy and scatter put it out of primary-structure consideration. It is qualified for secondary structure and interior hardware.
Sources
- FAR 25.853 — Compartment interiors
- Stratasys ULTEM 9085 material data sheet