Select Print Material

Choose 3D print material → match props to functional reqs. Covers FDM filaments (PLA, PETG, ABS, ASA, TPU, Nylon) + SLA resins (standard, tough, flexible, castable) w/ detailed property compare for strength, temp, chemical, flex, post-process.

Use When

• Specific mechanical reqs (tensile, impact, flex)
• Temp-sensitive (hot|cold)
• Chemical|UV|outdoor exposure
• Food-safe|biocompat
• Balance printability vs perf for proto vs prod
• Troubleshoot material-related fails
• Optimize cost vs props for prod runs

In

• functional_requirements: Load type (tensile|compress|bend|torsion), magnitude, duty cycle
• environmental_conditions: Temp range, UV, chemical, moisture
• mechanical_properties_needed: Strength, flex, impact, fatigue
• surface_finish: Appearance, post-process
• printability_constraints: Printer caps (heated bed, enclosure), user level
• special_requirements: Food safe, biocompat, electrical, transparency

Do

1. ID Primary Req Category

Dominant req drives selection:

Mechanical Perf:

• High strength under load
• Impact|shock absorption
• Flex|elastic behavior
• Fatigue resistance (repeated load)

Env Durability:

• High|low temp
• UV|outdoor weathering
• Chemical (solvents, oils, acids)
• Moisture|water

Special Apps:

• Food contact safety
• Biocompat (medical)
• Electrical (insulation, conductivity)
• Optical (transparency, color)

Printability/Cost:

• Easy print for protos
• Min warp|support
• Low cost for large parts
• Wide availability

→ Primary req ID'd ("outdoor UV" or "high impact").

If err: multi reqs equally critical → decision matrix scoring (Step 6).

2. Material Filters

Filter 1: Process

• FDM: All thermoplastics
• SLA: All resins
• Printer constraints: Heated bed (60-110°C) for ABS|ASA|Nylon; enclosure for ABS|ASA

Filter 2: Temp Range

Operating Temperature → Minimum Material Glass Transition (Tg):

< 45°C:  PLA, PLA+, Standard Resin, Tough Resin
< 60°C:  PETG, Flexible Resin
< 80°C:  ABS, ASA, CPE
< 100°C: Nylon, Polycarbonate, High-Temp Resin
> 100°C: PEEK, PEI (Ultem) - specialty printers only

Filter 3: Mechanical

High tensile strength:     Nylon > ABS/ASA > PETG > PLA > TPU
High impact resistance:    Nylon > PETG > ABS > ASA > PLA
Flexibility:              TPU > Flexible Resin > PLA (brittle)
Fatigue resistance:       Nylon > PETG > ABS > PLA

Filter 4: Env

UV resistance:            ASA > PETG > ABS > PLA (poor)
Chemical resistance:      Nylon > PETG > ABS/ASA > PLA
Outdoor durability:       ASA > Nylon > PETG > PLA (degrades)
Moisture resistance:      ABS/ASA > PETG > PLA > Nylon (hygroscopic)

→ 2-5 candidates remain.

If err: no material passes → relax least-critical req or post-process (UV coat for PLA).

3. Compare Properties

FDM Filament Properties

Material	Print Temp	Bed Temp	Tensile Strength	Elongation	Tg/HDT	UV Resist	Ease	Hygroscopic
PLA	190-220°C	50-60°C	50-70 MPa	5-7%	55-60°C	Poor	Easy	Low
PLA+	200-230°C	50-60°C	60-75 MPa	10-15%	60-65°C	Poor	Easy	Low
PETG	220-250°C	70-85°C	50-60 MPa	15-20%	75-80°C	Good	Medium	Medium
ABS	230-260°C	95-110°C	40-50 MPa	20-40%	95-105°C	Fair	Hard	Low
ASA	240-260°C	95-110°C	45-55 MPa	15-30%	95-105°C	Excellent	Hard	Low
TPU	210-230°C	40-60°C	30-50 MPa	400-600%	60-80°C	Good	Medium	Low
Nylon	240-270°C	70-90°C	70-80 MPa	50-150%	75-90°C	Excellent	Hard	Very High

Notes:

• Tensile: Higher = stronger pull
• Elongation: Higher = more flex before break
• Tg/HDT: Glass transition|heat deflection temp (max op)
• Ease: Print difficulty (warp, adhesion, stringing, supports)
• Hygroscopic: Water absorb (needs dry box)

SLA Resin Properties

Resin Type	Cure Time	Tensile Strength	Elongation	HDT	Hardness	Best For
Standard	2-4s	45-55 MPa	6-8%	60-70°C	82-85 Shore D	Miniatures, prototypes
Tough	4-6s	55-65 MPa	15-25%	70-80°C	80-85 Shore D	Functional parts, snaps
Flexible	6-8s	5-10 MPa	80-120%	50-60°C	60-70 Shore A	Gaskets, grips
High-Temp	8-12s	60-70 MPa	6-10%	120-150°C	85-88 Shore D	Heat-resistant parts
Castable	3-5s	35-45 MPa	8-12%	60°C	80 Shore D	Jewelry (lost-wax)

→ Props compared, 1-3 top candidates ID'd.

If err: props unclear → manufacturer datasheets via WebFetch.

4. Eval Printability Tradeoffs

Easy (PLA, PLA+):

• Min warp, good bed adhesion
• Wide temp tolerance
• Low stringing, easy supports
• Beginner|proto ideal
• Tradeoff: Lower temp resist, UV degrade, brittle

Medium (PETG, TPU):

• Mod warp (PETG needs 70°C+ bed)
• Some stringing (tune retraction)
• TPU needs direct drive + slow speed
• Good strength-ease ratio
• Tradeoff: PETG strings, TPU hard overhangs

Hard (ABS, ASA, Nylon):

• Severe warp w/o enclosure
• Strong fumes (ABS|ASA need ventilation)
• Nylon extremely hygroscopic (dry box req)
• High bed temps (95-110°C) + chamber heat
• Tradeoff: Excellent mechanical+env

Cost:

Material cost per kg (typical):
PLA:    $15-25
PETG:   $20-30
ABS:    $18-28
ASA:    $25-35
TPU:    $30-45
Nylon:  $35-55
Standard Resin: $30-50/L
Specialty Resin: $60-150/L

→ Printability vs printer caps + user. Decision balances perf vs constraints.

If err: material too hard for setup → easier alt + design changes (thicker walls, fillets).

5. Special Reqs

Food Safety:

• Safe printed correctly: PLA, PETG (w/ food-safe additives)
• Never safe: ABS, ASA (toxic additives), Nylon (porous)
• Reqs: Food-safe nozzles (stainless not brass), seal w/ food-safe epoxy
• Note: FDM layers trap bacteria — SLA smooth resin better

Biocompat (medical|dental):

• FDM: Nylon (some grades), PLA (limited)
• SLA: Medical-grade certified resins
• Warning: Home 3D not sterile; consult regs for medical

Electrical:

• Insulation: PLA, PETG, ABS, ASA all good (>10^14 Ω·m)
• Conductivity: Conductive filaments (carbon black, metal-fill)
• Notes: Moisture (Nylon) ↓insulation

Transparency:

• FDM: Nearly impossible (layer scatter); thin walls + extensive polish
• SLA: Clear resins → transparency w/ post-process (sand|polish|coat)

UV Resist:

• Excellent: ASA, Nylon
• Good: PETG, TPU
• Poor: PLA, ABS

→ Special reqs verified vs caps.

If err: doesn't meet → post-process (UV-resist coat on PLA) or diff material.

6. Final Selection Decision Matrix

Score candidates across weighted criteria:

Outdoor functional part example:

Criterion	Weight	PLA	PETG	ABS	ASA	Nylon
UV Resistance	30%	1	6	5	10	9
Strength	25%	6	7	6	7	9
Printability	20%	10	7	4	3	3
Temperature	15%	2	6	8	8	9
Cost	10%	10	8	8	6	4
Weighted Total		5.35	6.80	5.90	7.25	7.45

Score: 1 (poor) → 10 (excellent)

Decision: Nylon highest (7.45) but ASA (7.25) close + better printability. Select ASA if enclosure, else PETG (6.80).

→ Final selected w/ documented rationale.

If err: unclear → default PETG (FDM) or Tough Resin (SLA) — best all-around.

7. Document Settings

FDM template:

material: PETG
brand: "PolyMaker PolyLite"
color: "Blue"
nozzle_temp: 245°C
bed_temp: 80°C
chamber_temp: ambient
print_speed: 50mm/s
retraction_distance: 4.5mm
retraction_speed: 40mm/s
cooling: 50% (after layer 3)
notes: "Strings moderately, Z-hop helps. Dried 6h at 65°C."

SLA template:

resin: "Anycubic Tough Resin"
color: "Clear"
layer_height: 0.05mm
exposure_time: 6s
bottom_exposure: 40s
lift_distance: 6mm
lift_speed: 65mm/min
notes: "Post-cure 15min at 60°C for full strength. Brittle without cure."

→ Settings documented in project notes|slicer profile.

If err: start manufacturer recommended → iterate + document.

Check

• Primary req ID'd (mech|env|special)
• Candidates filtered by process, temp, reqs
• Props compared via table|datasheet
• Printability vs printer caps
• Special reqs checked
• Final via decision matrix w/ weighted priorities
• Settings documented for reproducibility
• Cost + availability verified for quantity

Traps

1. PLA for everything: Easy but unsuitable >50°C, outdoor, long-term durability
2. Ignore hygroscopy: Nylon+TPU absorb moisture → bubbling, poor adhesion, brittle. Dry box.
3. ABS w/o enclosure: Severe warp w/o heated chamber; ASA slightly better but still needs
4. Assume food safety: FDM porous traps bacteria; true safety needs sealing|SLA smooth
5. Over-design strength: Expensive Nylon when PETG enough; overkill wastes $ + adds difficulty
6. Underestimate temp: Parts near motors, heated beds, cars reach 60°C+ → PLA softens
7. UV neglect: PLA+ABS yellow+degrade in sun within months; use ASA or coat
8. Wet filament: Moisture → steam bubbles in extruder, weak adhesion, stringing — always dry hygroscopic
9. Ignore fumes: ABS+ASA emit styrene; needs active ventilation
10. Resin handling: Uncured = skin sensitizer + toxic; always gloves + ventilated

→

• prepare-print-model: Slicer settings for material
• troubleshoot-print-issues: Fix material fails
• Dry Filament (future): Drying for hygroscopic
• Post-Process 3D Prints (future): Sand, vapor smooth, paint, anneal