PETG vs PLA: The Ultimate Strength Comparison Guide for 3D Printing

When choosing between PETG and PLA filaments for your next 3D printing project, understanding their mechanical properties can make the difference between a successful print and a failed one. At Eolas Prints, we manufacture both materials in-house in Cantabria, Spain, ensuring consistent quality backed by our ISO 9001 and ISO 14001 certifications.

Understanding the Strength Fundamentals

Tensile Strength: The Numbers Tell Part of the Story

PLA typically demonstrates higher raw tensile strength at around 50-60 MPa, while PETG ranges from 40-50 MPa. However, these numbers only tell part of the story. PLA's strength comes with a critical weakness - brittleness. When PLA reaches its limit, it fails catastrophically, shattering rather than deforming.

PETG, despite lower tensile numbers, exhibits superior toughness. It can absorb significantly more impact energy before failure, making it ideal for functional parts that need to withstand real-world stress.

Impact Resistance: Where PETG Shines

The most significant difference between these materials lies in their impact resistance. PETG's flexibility allows it to bend and deform under stress rather than breaking. This makes it perfect for:

• Protective cases and housings
• Tool handles and grips
• Mechanical components subject to vibration
• Parts that might be dropped or knocked around

PLA's rigidity makes it excellent for structural components that need to maintain their shape, but poor for applications requiring shock absorption.

Temperature Performance: A Critical Factor

Heat Resistance Comparison:

• PLA: Begins softening around 60°C (140°F)
• PETG: Maintains integrity up to 80°C (176°F)

This 20°C difference opens up entirely different application possibilities. PETG works for automotive interior parts, outdoor summer applications, and kitchen accessories, while PLA is limited to stable, room-temperature environments.

Real-World Application Testing

For Prototyping: PLA excels due to its ease of printing, minimal warping, and excellent surface finish. The brittleness isn't a concern for visual prototypes or fit-testing parts.

For Functional Parts: PETG dominates with its chemical resistance, impact toughness, and temperature stability. It's ideal for brackets, housings, containers, and mechanical components.

For Educational Projects: PLA's forgiveness during printing makes it perfect for beginners, while PETG rewards experienced users with more durable results.

Chemical and Environmental Resistance

PETG demonstrates superior resistance to common household chemicals, cleaning agents, and oils. It also handles UV exposure better than PLA, though neither is ideal for long-term outdoor use without UV-resistant additives.

Both materials absorb moisture from air, but PETG is less affected by humidity during use, maintaining consistent properties across different environmental conditions.

Making the Right Choice for Your Project

Choose PLA when:

• Learning 3D printing or teaching others
• Creating prototypes, models, or decorative items
• Working in temperature-controlled indoor environments
• Prioritising ease of printing and surface finish
• Budget constraints favor lower-cost material

Choose PETG when:

• Creating functional parts requiring durability
• Applications involve temperature exposure above 50°C
• Parts need impact resistance or flexibility
• Chemical resistance is important
• Long-term durability outweighs printing convenience

Expert Recommendations from Eolas Prints

After extensive testing with both materials in our Cantabria facility, we recommend PETG for functional parts, protective components, and applications requiring longevity. PLA remains excellent for prototyping, educational use, and decorative applications.

Our technical support team can help you select the right material for your specific application. With our free shipping over €100 to most EU countries and next-day delivery within Spain, you can start your project with confidence.

Conclusion

While PLA offers higher raw tensile strength and easier printing, PETG provides superior impact resistance, temperature stability, and overall durability for functional applications. The choice depends on your specific project requirements, printing experience, and intended use.

Both materials have their place in professional 3D printing, and understanding their strengths helps you make informed decisions that lead to successful projects.

 

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