Top Recommendation: HP 3D High Reusability PA 11
Low-Temperature Toughness
PA11’s molecular chain exhibits greater flexibility than PA12, delivering superior impact resistance at -20°C to prevent brittle fractures. Despite its higher glass transition temperature (~46°C) compared to PA12, empirical tests confirm retained ductility in subzero conditions.
Snap-Fit Compatibility
With 5-10% elongation at break, PA11 allows elastic deformation for snap-fit assemblies. While its yield strength (~45 MPa) is slightly lower than PA12, structural optimizations (e.g., reinforcing ribs) can compensate.
Environmental Resistance
Inherently moisture-resistant and UV-stable for outdoor use. For extreme weathering, post-process UV-protective coatings are recommended.
Manufacturing Feasibility
PA11 is fully compatible with MJF systems, achieving comparable dimensional accuracy (±0.3% tolerance) to PA12, ideal for intricate housing geometries.

Alternative: TPU (Thermoplastic Polyurethane)
Pros:
Exceptional flexibility (>300% elongation at break), maintaining elasticity down to -40°C.
Cons:
Lower rigidity (Shore 80A-95A) may compromise structural load-bearing. Surface prone to dust adhesion; anti-fouling coatings are advised.

Non-Recommended Materials
PA12: Impact strength drops ~40% at -20°C; snap-fit joints risk fatigue failure.
PA12 GB (Glass-Beefed): Glass fibers exacerbate brittleness in cold environments; only suitable for rigid, non-snap components.

Validation Protocol
Prototype Testing:
Freeze PA11 snap-fit samples at -20°C for 24 hours, followed by:

Impact testing (e.g., ASTM D256 Izod/drop weight).
10+ snap assembly/disassembly cycles.
Post-Processing:

Vapor polishing for surface sealing.
Annealing (80°C/2hr) to relieve residual stresses and enhance thermal stability.

Conclusion: HP PA11 optimally balances low-temperature toughness and snap-fit functionality for MJF-printed housings. TPU is viable only if extreme flexibility outweighs rigidity requirements. Prioritize PA11 prototyping to validate performance under operational conditions.

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