When you’re looking at making something out of plastic, you need a material that provides a delicate balance of features. It has to have a high melting point, but not so high that it’s completely not moldable. While you want to be able to shape it in the ways you need, once it’s cooled, you also need it to be strong enough to take a beating.
Polyethylene terephthalate glycol, or PETG, offers all of these benefits and more. Read on to learn more about printing PETG and why it’s such a popular option among commercial and private plastics manufacturers alike.
What Is PETG?
Before we dive into all the advantages PETG can provide, let’s talk some about what it is. Polyethylene terephthalate glycol, better known as PETG, is a variety of polyester that can be used in 3D printing. It’s a thermoplastic, which means it’s solid at room temperature but gets softer and eventually turns into a liquid as it’s heated up.
PETG is a subcategory of a polyethylene terephthalate that is more durable and heat-resistant than its standard PET cousin. As we’ll discuss more later, while PETG is more heat-resistant than standard PET, it still has relatively low melting temperatures. This makes it easy to form into a wide variety of shapes, including filament used for 3D printing.
How Is It Made?
PET was invented in 1941 when Joh Whinfield and James Dickson combined phthalic acid and glycol to create a material that could be pulled out into long fibers. While the material was revolutionary in the textile and food packaging world, it still had some problems. In particular, when it gets hot, PET tends to crystallize, which turns it opaque and makes it weaker.
PETG swapped out the traditional glycol used in PET production for cyclohexane dimethanol. This helps to prevent crystallization at higher temperatures, making the material stronger. The inclusion of cyclohexane dimethanol is what makes PETG suitable for use in 3D printing and other such higher temperature applications.
As we’ve mentioned, PETG is enormously popular as a 3D printing material. Many home crafters use a method of 3D printing known as fused deposition modeling or FDM. The process involves melting filament at the bring head and then laying it down in layers to build your object; PETG’s melting qualities make it a perfect choice for this.
Because PETG is so much more stable than standard PET, it has also gained popularity in manufacturing industries. You’ll often see it used in packaging, both for retail and medical uses, since it’s so durable and heat-resistant. It’s also popular as an electronic insulator since it won’t melt when the components warm up.
One of the major questions when it comes to plastics these days is what sort of impact they have on the environment. Traditional petroleum-based plastics are terrible for the environment before, during, and after their production.
Petroleum is a non-renewable resource. The production process releases tons of deadly chemicals into the atmosphere, and petroleum-based plastics do not break down over time.
While PETG is not fully biodegradable, it is easier to break down than some traditional plastics. There are chemicals that can easily break down the polymer chain that makes up PETG, reducing it to its original components. Those components can then get recycled into new plastics, ensuring we make the most of those non-renewable resources.
Part of the reason PETG has gotten as popular as it has is because of the improved strength it provides compared to standard PET. Manufacturers need plastic parts to stand up to certain stresses, and normal PET isn’t strong enough to get the job done. This is especially true of the plastic that has been heated to mold it into a specific shape.
But because PETG uses a different molecule in its makeup, it’s much more suited to carry heavy loads and stand up to wear and tear. In addition to overall strength, PETG is also much more impact-resistant. This makes it a great option for packaging, displays, and signs that may take a beating during their life.
As plastics have become more and more ubiquitous in our world, the question of affordability has become more critical. Saving even a few cents per part on plastics can help manufacturers cut production costs by thousands of dollars a year. Thanks to its simple manufacturing process, PETG is one of the most affordable plastics on the market today.
Affordability is also important for home crafters making 3D printed objects. There’s little point in 3D printing a laptop stand for yourself if the cost of the materials will be higher than the price to purchase one from a retailer. PETG is affordable enough to make it a viable option for people using 3D printers at home.
Another big question for plastics producers, whether commercial or personal, is whether a material is food safe. Some plastics may break off and shed microplastics into your food. Others can leech dangerous chemicals into food that make it unsafe to eat.
PETG has none of these problems; in fact, it has been popular as a food packaging material since 1952. This makes it a great option for manufacturers who want to mold custom containers that can stand up to the stresses of shipping. It’s also great for home 3D printers who want to make their mom a coffee mug for Mother’s Day or print a new butter dish for their breakfast table.
Of course, the amazing formability of PETG is another one of its huge advantages. This plastic provides the best of both worlds in that it’s heat-resistant, but not unmeltable. At the right temperature (above about 500 F), PETG becomes very soft and pliable without losing any of its original strength.
This kind of formability makes PETG a perfect choice for manufacturers looking to mold plastic pieces for a variety of uses. And this working temperature also makes PETG a feasible option for 3D printers, since the filament can be melted at the print head. It will bond with the layer below it, hardening into one solid piece.
Whether you’re a home crafter or an industrial manufacturer, getting the right color in your plastics is important. You may need something to have the right presentation, or you might need it to match other parts you’re manufacturing. Some plastics take color better than others, and thankfully, PETG is one of those that takes color beautifully.
Pure PETG is colorless and transparent, making it the perfect canvas to make your technicolor plastic dreams come true. You can use it to create interesting visual effects and stunning colors. You can also mix a few different colors together to create different appearances for your plastics.
One of the things home 3D printers need to take into consideration is the toxicity of the material they’re working with. Some materials tend to put off fumes that can be incredibly dangerous. When working with these materials, you may find you have to use special ventilation or wear PPE to stay safe.
Luckily, PETG comes with none of these concerns, as it is non-toxic during the 3D printing process. Better than that, it is odorless, so you don’t even have to worry about your home smelling like burning plastic. You can use your standard safety precautions with your 3D printer, confident that your home is safe.
Disadvantages of PETG
Of course, PETG isn’t a miracle material, and like anything, it has its downsides. In particular, PETG’s heat resistance makes it somewhat demanding to work with, especially for a home crafter. You have to be sure your printer can operate within specific parameters or the filament won’t behave the way it’s supposed to.
PETG also tends to ooze more during the printing process than PLA or ABS, so you may have to use some different bridging techniques to stabilize it. If it’s not stored correctly, PETG will absorb water and become more brittle. Like any plastic, PETG can have a negative environmental impact if not handled correctly.
Learn More About Printing PETG
In a world dominated by plastics, PETG offers a fantastic combination of affordability, strength, and formability. This material has a relatively high melting point, but it still retains its strength after it’s been melted. It’s also non-toxic and relatively cheap to produce, which makes it a great option for home crafters and large-scale manufacturers.
If you’d like to learn more about printing PETG, check out the rest of our site at 3DF Filaments.