PETG vs PLA – How Do These Common 3D Printing Filaments Compare?

PLA and PETG are two of the most popular materials for desktop FDM 3D printing. But how do these thermoplastics actually compare in terms of properties, print quality, ease of use, and suitable applications?

We’ll examine the key similarities and differences between PLA (polylactic acid) and PETG (polyethylene terephthalate glycol-modified) filaments to help you choose the right material for your next project.

Overview Of PLA and PETG Filaments

Both PLA and PETG are considered easy-to-print filaments, suitable for beginners while also offering advantages for experienced users. Let’s start with a quick overview:

PLA

• Made from renewable plant-based materials like corn starch.
• Biodegradable.
• Low printing temperature around 190°C-220°C.
• Hard, brittle plastic with low flexibility.
• Great surface finish and detail.
• Easy to print with good bed adhesion.
• Limited thermal and chemical resistance.
• Wide range of colors.

PETG

• Made from PET plastic with glycol modifications.
• Not biodegradable.
• Prints around 230°C-250°C.
• Durable and flexible plastic.
• Good surface quality and layer adhesion.
• Can be tricky with bed adhesion and stringing.
• Excellent thermal resistance and chemical resistance.
• Variety of translucent color options.

Keep this overview in mind as we delve into the comparative details.

Print Quality Comparison

A key consideration is the actual print quality each filament can achieve. Here’s how PLA and PETG compare:

• Resolution – PLA can produce slightly sharper prints with finer details thanks to its low printing temperature. PETG’s higher temperature can lead to some line blurring.
• Overhangs – PLA’s higher hardness results in less drooping on overhangs and bridging compared to flexible PETG.
• Layer adhesion – PETG creates strong interlayer bonding while PLA layers can separate more easily under stress.
• Warping – PETG’s flexibility makes it more prone to warping off the print bed compared to rigid PLA.
• Stringing – PETG is notorious for stringing during prints. PLA generally strings less thanks to its fast solidification.
• Fumes and odor – PLA gives off minimal fumes while PETG has a noticeable acidic smell when printing.

Overall, PLA eeks out PETG in pure print quality, but PETG’s advantages in layer adhesion and reduced warping make both good choices.

Material Properties Face-Off

The inherent properties and composition of these plastics greatly affect their real-world performance and applications.

• Strength – PETG is stronger than PLA in terms of durability, tensile strength, and flexural strength.
• Flexibility – PETG has much higher flexibility vs the rigid and brittle nature of PLA.
• Heat resistance – PETG offers excellent thermal resistance up to 70-80°C whereas PLA softens around 60°C.
• Chemical resistance – PETG also withstands solvents and acids much better than PLA.
• UV resistance – PETG holds up better than PLA over time when exposed to sunlight and UV.
• Glass transition – PLA becomes brittle below its glass transition around 55°C. PETG retains ductility below its 75°C transition.

This gives PETG the edge for high-performance engineering applications, while PLA is suitable for decorative prints.

Ease of Printing Comparison

In terms of ease-of-use, PLA generally offers a smoother printing experience:

• PLA can print on a wider variety of build surfaces like glass, PEI, and BuildTak. PETG often requires print surfaces like BuildTak.
• PLA needs lower nozzle/bed temperatures that are less likely to cause jams or oozing issues.
• PLA has minimal risk of layer delamination or warping when properly adhered.
• PLA’s faster cooling means less time for sagging, drooping, or elephant’s foot.
• PLA emits fewer fumes and odors during printing compared to PETG.

However, PETG allows more flexibility in dialing in print settings to match your machine and environment. And its interlayer bonding can actually help cover small print defects.

Suitable Print Applications

Considering all the factors above, here are typical applications both filaments excel at:

PLA Ideal For:

• Miniatures, gaming pieces, and figures needing fine details
• Decorative objects and ornamental prints
• Low-temperature prototyping molds and fittings
• Direct food contact applications like containers
• Biodegradable prints and environmentally friendly products

PETG Great For:

• Functional prints needing durability and heat resistance
• Tools, jigs, fixtures and workshop items
• End-use parts and final products rather than prototyping
• Outdoor use with exposure to sunlight and moisture
• Mechanical pieces needing flexibility and impact resistance
• Chemical and laboratory equipment like containers

Which One Should You Choose?

With this full comparison in mind, should you choose PLA or PETG for your next project?

For most beginner uses and smaller prints, PLA is easier to handle and provides great quality. The low printing temperature helps avoid many issues new users face. The wide range of colors and opaque finishes make it ideal for decorative prints with fine details.

In terms of material properties, PETG really shines for advanced engineering uses where temperature resistance, chemical compatibility, and durability are critical. The layer bonding resists breakage and delamination under load. PETG finishes have a glossy transparency great for lights, lenses, water containers, and functional prints.

Consider your specific application and required material qualities. For larger, stronger, outdoor-usable prints, PETG is probably the best option. But for small indoor prints, prototyping, and display objects, user-friendly PLA fits the bill.

Matching your filament to the model and its real-world uses ensures optimal long term print results.

Alternatives To PLA and PETG

While PLA and PETG represent over 80% of consumer 3D printing, other materials also deserve consideration:

• ABS and ASA are stronger high-temperature resins but require more controlled printing environments.
• Nylon filaments like PA6 offer excellent layer adhesion and are extremely durable for mechanical uses.
• More exotic filaments like PEEK and PEKK can withstand sterilization and high heat for engineering applications.
• Flexible TPU filaments create rubbery prints for bendable objects, phone cases, grips, and more.

Don’t limit yourself to just PLA and PETG – explore this wide world of 3D printing materials to perfectly match the function you need.

Make the Best Choice For Your Needs

For most users, PLA and PETG cover the majority of common printing applications ranging from prototypes to end-use parts and products. Think about layer adhesion, flexibility, heat and chemical resistance, finishing, and accuracy to pick the right filament for each job.

Understanding the core differences between these two standard materials helps ensure ideal prints with the desired properties in any situation. Equipped with this knowledge, you can tackle a huge range of projects in PLA or PETG to achieve the perfect printed object.

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