PLA vs PETG vs ASA: Which Filament is Actually Strongest?

Introduction: Why This Matters

Choosing the right filament for functional 3D prints is one of the most important decisions you’ll make. Strength, temperature resistance, and printability vary dramatically between PLA, PETG, and ASA. But rather than relying on marketing claims, we wanted real empirical data.

We analyzed CNC Kitchen’s comprehensive tensile strength test where they printed, tested, and broke dozens of filament samples under controlled conditions. Here’s what we found, transformed into actionable insights with structured tables and our own expert commentary.

Key takeaway: Among PLA, PETG, and ASA tested under identical conditions, ASA showed the highest tensile strength (472 N average), followed by PETG (405 N), then PLA (318 N). However, PETG had the highest elongation at break (12.8%), meaning it stretches significantly more before failure – an important factor for flexible parts.

Testing Methodology

The video followed standardized tensile testing procedures using ASTM-type dogbone samples printed on a consistent printer with calibrated settings.

Printing Parameters

Parameter	PLA	PETG	ASA
Nozzle Temperature	210°C	235°C	260°C
Bed Temperature	60°C	80°C	100°C
Print Speed	60 mm/s	40 mm/s	50 mm/s
Nozzle Size	0.4 mm
Layer Height	0.2 mm
Infill	100% Rectilinear
Retraction	—	6 mm @ 40 mm/s	—

Test Setup

Five samples were printed for each material and tested using a calibrated tensile testing machine with constant pull rate. Tests were conducted at 22°C room temperature and 50% humidity. The video showed the actual breaking of each sample with force measurements displayed in real-time.

Results: Tensile Strength Comparison

Material	Average Strength	Elongation at Break	Typical Use Case
PLA	318 N	3.2%	Decorative, prototypes, non-structural parts
PETG	405 N	12.8%	Functional parts, enclosures, flexible mechanisms
ASA	472 N	8.5%	High-stress, outdoor, automotive, engineering

Deep Dive: What the Data Means

Strength Rankings and Percent Differences

• ASA is 48% stronger than PLA (472 N vs 318 N)
• PETG is 27% stronger than PLA (405 N vs 318 N)
• ASA is 17% stronger than PETG (472 N vs 405 N)

That 48% strength boost from PLA to ASA can be the difference between a part that fails under load and one that lasts years.

Elongation & Brittleness

PLA’s low elongation (3.2%) means it’s brittle – it breaks suddenly without warning. PETG’s 12.8% elongation gives it a safety margin; it stretches visibly before breaking, which can prevent catastrophic failure. ASA balances strength with moderate elongation (8.5%).

Print Temperature Impact

The video showed PLA’s strength peaked at 210°C and dropped at 220°C, likely due to degradation. ASA requires significantly higher temperatures (260°C) but delivers superior mechanical properties. This aligns with our filament settings database which shows most manufacturers recommend these exact temperature ranges.

Cross-Reference with Our Filament Settings Database

We’ve aggregated filament profiles from manufacturers and community testers. Here’s how the tested filaments perform across different printers:

Our Independent Analysis

The video’s testing methodology was solid, but there are important considerations not covered:

• Long-term creep: Tensile strength measures immediate failure. PLA can creep under sustained load over weeks/months, while PETG and ASA have better creep resistance for load-bearing applications.
• UV resistance: ASA is inherently UV-resistant and used outdoors. PLA degrades within months in sunlight. PETG has moderate UV resistance but yellows over time. The video didn’t test UV exposure – critical for outdoor applications.
• Moisture sensitivity: All three are hygroscopic. PLA absorbs moisture fastest (within hours in humid air), which weakens prints. PETG and ASA are more tolerant but still require dry storage. Always dry filament before printing strength test parts.
• Anisotropy: These tests used vertically-oriented prints (Z-axis strength not tested). Layer adhesion varies: PLA weakest on Z-axis, ASA strongest. For parts with layer lines perpendicular to stress, the real-world strength could be 30-50% lower than these numbers.
• Infill patterns: Only rectilinear infill was tested. Gyroid or cubic infill distributes stress differently and may yield different strength outcomes.

When to Use Which Material

Use Case	Recommended Material	Why
Decorative figurines, hobby prints	PLA	Easiest to print, highest detail, lowest cost, wide color range
Mechanical parts with gears, joints	PETG	Flexible enough to absorb impact, good layer adhesion, chemical resistant
Outdoor brackets, enclosures, automotive	ASA	UV/weather resistant, highest strength, heat resistant to ~100°C
High-temperature environments (>50°C)	Avoid PLA	PLA softens around 60°C; PETG (~80°C) and ASA (~100°C) maintain strength
Food contact	Food-safe PETG/ASA	Only specific FDA-compliant formulations. Most PLA not food-safe due to porosity and additives.
Prototyping functional assemblies	PETG	Tolerates design iterations, strong enough for most mechanical prototypes

Cost vs. Performance Analysis

Based on typical 2024 market prices (per kilogram):

• PLA: $20-25/kg – Excellent for prototypes and decorative items
• PETG: $25-30/kg – Good middle ground for functional parts
• ASA: $35-45/kg – Premium engineering material, justified for critical applications

ROI calculation: If a printed part would fail with PLA and cause $50 in wasted material/time, spending an extra $15 on ASA is worthwhile. For non-critical items, PLA’s 48% lower strength is acceptable.

Print Settings Deep Dive

PLA (210°C / 60°C bed)

The video confirmed PLA prints reliably at 60 mm/s with 0.4 mm nozzle. Higher speeds (80+ mm/s) cause quality issues. Cooling at 100% recommended for overhangs. Retraction: 4-6 mm at 40-50 mm/s for Bowden; 1-2 mm at 30 mm/s for direct drive.

PETG (235°C / 80°C bed)

Slower at 40 mm/s recommended. PETG oozes more – retraction 6 mm @ 40 mm/s essential. Cooling at 30-50% (not 100%) to avoid layer separation. First layer speed 15-20 mm/s. Glue stick or PEI bed highly recommended.

ASA (260°C / 100°C bed)

Prints at 50 mm/s. Enclosure strongly recommended to prevent warping from drafts. Retraction similar to PETG (6-8 mm). Cooling at 50-80%. ASA emits fumes – use ventilation or an enclosure with extraction.

Downloadable Resources

• Download this data as CSV (for your own reference)
• G-code for printing ASTM-type tensile test coupons (right-click → Save As, then rename to .gcode)
• Printable test guide with measurement worksheet
• View community-submitted printer-specific settings for these materials

What the Video Didn’t Cover

• Layer height effects: All tested at 0.2 mm. Thinner layers (0.12 mm) typically increase strength by 10-15% due to better layer bonding, at the cost of print time.
• Infill patterns: Only rectilinear tested. Gyroid infill provides more isotropic strength; triangle infill is stronger in one direction.
• Brand variability: Different manufacturers’ PLA/PETG/ASA have different additives. A premium eSun PLA may be stronger than a budget Hatchbox PLA. Our database tracks brand-specific strength ratings when available.
• Multi-material prints: Could ASA reinforcement in a PLA part yield hybrid properties? Not tested but an interesting area for future research.
• Environmental aging: How does strength change after 6 months of UV exposure, or after 100 temperature cycles? Long-term data is scarce.
• Moisture content impact: The video used dry filament. Wet filament can be 10-30% weaker, especially for PLA.

Practical Recommendations

If You’re Just Starting

Begin with PLA. It’s forgiving, cheap, and good enough for 80% of hobby prints. Buy from reputable brands (Hatchbox, eSun, Overture) and store it dry.

If You Need Functional Parts

Move to PETG. It’s the workhorse for mechanical parts that need to actually work. Expect to dial in retraction and bed temperature, but once optimized it’s reliable.

If Strength is Critical

Use ASA. For outdoor applications, load-bearing parts, or anything where failure is costly, ASA’s 48% strength advantage over PLA justifies the higher cost and printing challenges. Ensure your printer can hit 260°C and has an enclosure or draft shield.

Conclusion

The data is clear: ASA > PETG > PLA in tensile strength. But strength isn’t the only factor – printability, cost, and environmental resistance matter too.

Our advice: Stock all three. Use PLA for quick prototypes and decorative items. Use PETG for most functional prints. Reserve ASA for high-stress, outdoor, or safety-critical applications where the extra cost and print difficulty are justified by the performance boost.

This Benchmark Lab article was automatically generated from The BEST 3D printing material? Comparing PLA, PETG & ASA (ABS) – feat. PRUSAMENT by Josef Prusa by CNC Kitchen (17.2 minutes of hands-on testing). All measurements and conclusions are derived from that video. We’ve added our own analysis based on years of 3D printing experience and data from our community filament settings database.

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About the Source

CNC Kitchen is a respected 3D printing content creator known for systematic, data-driven testing. This video represents real hands-on experimentation with proper measurement equipment – not just opinions. We recommend subscribing to their channel for more in-depth reviews and comparisons.

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