PLA vs. PETG: Key Differences and Full Comparison

PLA and PETG are two of the most popular types of filament used in fused deposition modeling (FDM) 3D printing. Each material has different characteristics and is best suited for different types of projects, but you might find it challenging to choose one if you’re a beginner. Knowing how PLA vs. PETG compares might help you pick the right filament for your project.

PLA vs. PETG: Side-by-Side Comparison

Polylactic acid (PLA) is the most commonly used 3D printing filament. The material is environmentally friendly, easy to work with, and suitable for food-grade parts.

Polyethylene terephthalate glycol (PETG) is a modified version of PET plastic used in water bottles and other plastic products. It has high tensile strength and higher stress resistance than PLA, characteristics that make it a better choice for high-impact or high-stress parts.

However, PETG is much more difficult to work with. PETG is highly hygroscopic and prone to stringing, factors that can reduce the part’s overall quality. Briefly, here’s how the PLA vs. PETG filaments compare.

PLA vs. PETG: What’s the Difference?

The first thing you might hear when getting into FDM 3D printing is that PLA is a better material for beginners than PETG. But why, exactly? Let’s find it out.

Material Characteristics  

The main difference between PLA and PETG is the type of material. PLA stands for polylactic acid, which is a natural and biodegradable compound. PLA filament is derived from sugar cane or corn starch; the manufacturing process transforms it into a thermoplastic monomer. However, the manufacturing process involves biomass resources rather than fossil fuels, as it happens with PETG.

PETG stands for polyethylene terephthalate glycol. This material contains the same monomers as PET plastic, but the glycol added to the molecular level increases strength, durability, impact, and temperature resistance.

As a thermoplastic polyester, PETG is a fully synthetic material derived from fossil fuels and other chemicals. It is recyclable but not biodegradable, and it is generally not considered renewable.

Beyond their fundamentally different structure, an essential distinction between PLA and PETG is the type of filaments that can be created with each of these materials. PETG can only be found as it is, but PLA can be enhanced by adding other materials to provide different properties.

For instance, PLA is used in blends that create wood and metal filaments. Wood filaments can vary from bamboo to cedar, pine, walnut, or coconut wood. These filaments can be used for printing natural-looking furniture or decorative objects.

To make metal filaments, PLA can be mixed with iron, steel, brass, bronze, or copper. These filaments are often employed in jewelry making and art 3D printing.

Pre-Printing Preparation

The actual distinctions between PLA and PETG become obvious before starting the printing process. Each filament type requires some pre-printing preparation, but the process is faster and more straightforward for PLA.

This filament isn’t very fuzzy about printing temperature, and while results are improved when printing on a heated bed, you don’t have to pre-heat the build plate. This means that you can set the build plate temperature and start printing right away — the bed will heat up during the printing process and provide sufficient stability and adhesion as the part gets heavier.

A lower hot end temperature also cuts down pre-heating time. You can start printing faster compared to PETG. In fact, PETG is susceptible to temperature changes and requires a properly heated bed and hot end. Otherwise, you may be faced with poor layer adhesion, delamination, stringing, and warping.

Since both the hot end and build plate temperatures are higher for PETG, you’ll have to wait longer before you can start printing. A similarity between PLA and PETG is the hygroscopic nature of both materials. They absorb moisture from the air and must be dried before printing to prevent defects.

The best way to dry both PLA and PETG is with a filament dryer. These boxes come with pre-set drying temperatures for specific materials and let you know when the filament is ready to use. Alternatively, you can dry both filaments in the kitchen oven or in a food dehydrator at a max temperature of 65°C (149°F) for four to six hours.

To determine the right drying temperature for your PLA filament, read the product label and set the oven at a temperature lower than the glass transition temperature of the specific filament you’re using.

Printing

PETG requires more pre-printing preparation, but things don’t get easier when it comes to actual printing. This is one of the most challenging filaments. Getting calibration just right is crucial for successful printing with PETG, and the actual parameters can vary from one filament brand to another — and, sometimes, even between various colors from the same brand.

In broad terms, PETG requires a hot end temperature between 230°C to 250°C (240°C/ 464°F is a sweet spot for most filaments) and a heated bed between 70°C and 90°C (158°F and 194°F). However, these values can change based on the printer you’re using.

For instance, Ender 3 users may find that 60°C is enough for the heated bed, while the hot end temperature could go as low as 220°C. On Prusa printers, PETG usually requires higher temperatures — about 85°C for the build plate and up to 260°C for the hot end.

PLA requires lower bed and nozzle temperatures, but what truly makes it different than PETG is its ability to handle temperature fluctuations better than PETG. This filament type doesn’t require an enclosure (although you can use one), but an enclosure is almost mandatory for PETG.

PLA is also less prone to stringing or warping. Due to its sticky surface, PETG is prone to stringing, which means that you also have to get the right parameters, including retraction speed and distance, infill pattern, and Z-offset. PLA doesn’t require all this tweaking, and you can usually obtain good results even when using the slicer software’s default settings.

Post-Processing

Another difference between PLA and PETG is the post-processing ease. If you’re not familiar with FDM printing, you should know that an object is built in layers. Depending on the resolution (layer height), the ridges between the layers may be more or less visible. However, post-processing is always necessary to remove them and obtain a smooth, shiny surface.

Both PLA and PETG can be smoothed in various ways, including sanding, coating, vapor smoothing, chemical smoothing, and heating treatments. However, PLA is less rigid once printed and a lot easier to post-process.

Part Quality

When discussing quality, it is important to consider the end purpose of your print. Do you need a highly aesthetical part or a very resistant one? In the first case, PLA is your best choice. This filament is easier to post-process and generally produces parts with high cosmetic quality.

However, PLA becomes rather brittle once printed, and it has lower resistance to impact and stress than PETG. Thus, it is not the best choice for parts that have to resist external forces. If strength and durability are more important than aesthetics, you should choose PETG.

PETG is also a good choice for parts printed for outdoor applications. As highlighted above, this thermoplastic has a higher glass transition temperature. Glass transition temperature is the temperature at which an amorphous material starts transitioning from solid to liquid, softening and losing its shape.

When kept under the elements, PLA is more likely to overheat and deform. PLA is also more susceptible to UV and chemical damage compared to PETG.

Applications

Its strength and durability make PETG the go-to choice for parts that require a high tensile strength or chemical resistance. This filament is often used for mechanical parts, holders or clamps, machine guards, display stands, medical implants, medical devices, and pharmaceutical packaging.

Despite its highly hygroscopic nature, PETG prints are fully waterproof. Food-grade PETG filament can be used for printing Tupperware, food and water containers, plates, cups, and other plastic items.

PLA is a food-grade material widely used for medical and food purposes. In the medical industry, it is typically used for implants, pins, rods, screws, and packaging. In the food industry, PLA filament can be employed for printing disposable tableware, food packaging, cups, and bags.

But the material’s versatility also makes it the perfect choice for printing works of art, jewelry, accessories, and even furniture. The only thing to keep in mind is that PLA is not a good choice for outdoor applications unless you’re using an enhanced type, such as wood or metal filament.

Price

Price-wise, there aren’t wide cost gaps between PLA and PETG, but the former is generally cheaper. A spool of PLA can cost anywhere from $17 to $100+, depending on the size and manufacturer. Factors like filament diameter and color can also influence costs. Metallic finishes and other specialty filaments are more expensive than standard PLA.

Things are similar for PETG, but this filament’s prices start around $22 for a standard (1kg) spool. The brand, color, diameter, and spool size can all affect the final price. Regardless of the filament, an important thing to keep in mind is that high-quality filament will cost you less in the long run.

Quality filaments, such as Hatchbox, Overture, or Prusament — to name just a few — are easier to print and less likely to cause defects. In 3D printing, defects typically mean that you have to throw away everything that’s already printed and start over.

PLA vs. PETG: 8 Must-Known Facts

1. PLA is the most common FDM filament used in 3D printing. The material has high cosmetic quality but low resistance to impact and stress.
2. PETG is somewhat less popular than PLA, but it still is one of the most common FDM printing filaments. It has high impact and stress resistance but lower cosmetic quality.
3. PLA is easier to print than PETG. It is less affected by environmental factors and produces quality prints even if the calibration isn’t ideal.
4. PETG requires perfect calibration. Results may vary based on the filament brand, printer, and even environmental factors such as room temperature or printer location. It is recommended to use an enclosure.
5. Both PETG and PLA are highly hygroscopic and must be dried before printing, but printing with slightly wet PLA can result in satisfactory prints. PETG has to be fully dried to obtain quality prints.
6. PETG is ideal for industrial prints, including mechanical parts, medical or pharmaceutical equipment, tools, and clamps.
7. PLA is ideal for arts and crafts, food-grade products, medical devices, implants, and furniture.
8. Both PLA and PETG are recyclable, but only PLA is biodegradable. PLA is derived from corn starch or sugar cane and degrades over time. PETG is plastic and is less environmentally friendly than PLA.

PLA vs. PETG: Which One Is Better? Which One Should You Use?

PLA and PETG have different characteristics and suit different applications. Choosing the best one comes down to your needs and purpose. If you want to print decorative items, accessories, miniatures, figurines, and the like, PLA is your best choice. This material is also the right choice for printing jewelry.

PETG is a better option for functional parts, especially parts that have to withstand stress or impact. This filament is also a better option for outdoor applications, as it has a higher temperature resistance. PETG also resists UV radiation and chemicals. However, if you’re new to 3D printing, starting with PLA and switching to PETG once you’ve gained some experience might be best.