Many enthusiasts and experts have debated among themselves the pros and cons of PLA and PETG as filament materials. Nowadays, because the information about both is abundant on the web, it’s easy to get overwhelmed, but that’s why we’re here with a simple comparison. PLA, also known as polylactic acid, is a natural material made of fermented plant starch. It’s one of the cheapest, most common filament materials in the market. PETG, Polyethylene terephthalate glycol, is a non-biodegradable oil-based polymer. It’s similar to that in plastic bottles, except for the addition of glycol which makes it more flexible and durable. Given this information, which is best for you? Here’s all that you need to know.
In order to choose a fitting material, whether it’s PLA or PETG, the decision should depend on what you want to print and how you intend on using the item. One of the reasons PLA is so common with amateur printing enthusiasts is that it is reasonably strong, but the PETG is stronger. While both have high tensile strengths, or in other words, can withstand a high amount of pressure, the PLA will simply snap when the pressure gets too much. Nevertheless, the PETG’s ductility gives it the ultimate advantage when it comes to toughness.
Since both materials have similar properties, they have similar uses. PETG and PLA can be used in making forks, spoons, plates, as well as, screws, bolts, and even prototypes. You should, however, keep in mind that when it comes to water containers and designs where the filament will be constantly subjected to water or sun, your best bet is the PETG because of its resistance to the elements, not to mention, the PLA is biodegradable. If you’re planning on creating complex designs, PLA would be the way to go.
The cost of each filament differs according to material, color, tolerance, and brand, but overall, PLA is cheaper than PETG, though not by much. You’ll only see a notable difference if you’re buying large quantities. It’s also important to note that the cost of PETG is because the element covers a wide range of uses from domestic to industrial. One more thing to keep in mind when judging price is that your failed PLA and PETG designs can be extruded into more filament and reused in other designs. Don’t forget that PLA is also naturally compostable which makes it safer for the environment.
We’ve mentioned before that PLA is more popular with beginners. It’s soft, yet strong which makes it perfect for a starter. Meanwhile, the tricky part when it comes to printing with PETG is that it requires a hotter temperature or else, according to this 3d printing filament comparison, the material gets stringy. Add to that, PLA is much more forgiving during the printing process, while PETG requires you to put more effort into perfecting the first layer of your print. Since PETG is denser and more sticky, you’ll need to add a separator between the material and the printing bed. The first layer has to be thick, yet perfectly level, too, which will require you to change the slicer’s settings.
PETG has an advantage when it comes to many aspects, but when it comes to appearance, PLA takes the prize. Polylactic acid is not only widely available, but it’s also available in an extensive range of colors. If you’re looking for a translucent filament, a color blend, or a glossy finish, you can find that when shopping for PLA. PETG also comes in a variety of colors, though not as much as PLA. Add to that, a smooth, glossy finish is much more guaranteed with PLA than with PETG.
The fumes exuded from melting plastic have always been a concern for some, but the good news is that such fumes are harmless. Until now, science has failed to produce concrete evidence regarding the toxicity of PLA and PETG fumes. While this means you shouldn’t worry, it doesn’t mean that you shouldn’t keep your 3D printing room properly ventilated, as long-term exposure to any type of fumes can potentially be harmful. As for food safety, both materials are generally food-safe, but you should check with your filament manufacturer because it’s not far off for some to add certain additives to their material to improve quality or color.
Because of PETG’s flexibility, it’s considered a perfect material for clips and hangers. While it is strong, it has a bit of giving due to its viscosity and stickiness which make each layer stronger than the one before. PLA, on the other hand, is quite brittle as it snaps once the load exceeds a certain amount, even worse, it gets more brittle with time. This goes back to two factors. First, the inherent brittleness of polylactic acid, and second, its high tendency to absorb moisture from the air. Needless to say, the material could get more brittle with certain color additives and with increased exposure to nature.
As mentioned above, PLA is a biodegradable material. When a material is already brittle and then is exposed to natural elements, it’s quite unlikely for it to last. That’s why PLA isn’t recommended for use in hot, humid climates and where it will be constantly exposed to water. On the contrary, PETG can survive powerful impacts, exposure to high temperatures and water, and is chemical-resistant. Granted, the material’s surface gets scratched easily, but that’s about it.
As you can see, the answer to the question of which is better is a little more complicated than usual. In a direct comparison, each material has its advantages. PLA is cheap, eco-friendly, easy to use, and looks great. PETG is more expensive and non-biodegradable, yet it’s stronger and more durable. Ultimately, it’s a matter of preference, skill, and intention. There’s no reason for you to buy PETG if you’re still figuring your way around the basics or if you want to reduce your plastic usage. On the other hand, if you want to make a water container or a durable TV mount, PLA won’t serve you well, regardless of how skilled you are.