davide
d62dfd13a8
- add skill package and SKILL.md with AM workflow, guardrails, and output structure - add technical reference corpus (DfAM, fatigue, defects, process parameters, compliance, cost) - add materials-db.json with polymer/metal data, roughness/post-processing ranges, and selection guides - add CLI tools: select_material.py and postprocess_route.py for material ranking and post-processing route generation
2.5 KiB
2.5 KiB
Polymer AM Materials
Primary database:
materials-db.json— contains all structured data (mechanical and thermal properties, print parameters, applications, warnings) for all polymeric materials. This file provides qualitative context and usage notes that cannot be structured in JSON.
How to use the JSON database
To select a polymeric material:
1. Filter by T_max_service (field thermal.T_max_service)
2. Filter by available process (field processes)
3. Compare UTS_min/max, elongation, E_min/max
4. Check biocompatible, uv_resistant, chemical_resistance if relevant
5. Use selection_guides.by_application for a quick shortlist
6. Read warnings before proceeding
Qualitative notes by family
FDM — Standard materials (PLA, PETG, ABS, ASA)
- PLA: entry-level, no temperature, no UV. First choice for rapid prototypes.
- PETG: better than PLA for chemical resistance and toughness. Stringing requires attention to settings.
- ABS/ASA: if HDT >80°C is needed. ASA for outdoor use. Both require an enclosure.
FDM — Engineering materials (PA12, PC, TPU)
- PA12: excellent toughness, hygroscopic — always pre-dry. Preferred for snap-fits and gears.
- PC: transparent, high HDT. Difficult to print. Consider SLS PA12-GF as an alternative for high temperatures.
- TPU: direct-drive only. Bowden extruder causes severe issues.
FDM — High-performance (PEEK)
- PEEK is the only choice for T >200°C in FDM. Cost and difficulty are very high.
- Consider PEEK SLS as an alternative (better isotropy but rare machines).
- CF-PEEK increases stiffness but reduces ductility — only if stiffness is the primary driver.
Continuous fiber composites (Markforged)
- Onyx + continuous CF can achieve UTS comparable to aluminum.
- Hard constraint: Markforged machines only. High cost but avoids metal AM for many structural applications.
SLS/MJF — Polymer powders
- PA12 SLS: reference standard. Good isotropy, free geometries, no supports.
- PA11: preferred when superior toughness is needed (impact, notches, elongation >40%).
- PA12-MJF: slightly better than SLS for surface finish and throughput. Full-color available.
- TPU SLS: excellent for flexible parts requiring complex geometries (not feasible in FDM).
SLA/DLP Resins
- Standard: maximum resolution for prototypes and aesthetic parts. Not for load-bearing use.
- High-Temp: only resin option for thermal molds and fixtures.
- Ceramic-filled: multi-step process (printing + debinding + sintering). Shrinkage 20-25% — compensate accordingly.