PETG filament has gained significant popularity in 3D printing, especially among beginners. It has become one of the most sought-after materials in this field. To help you get started with PETG 3D printing, we have put together some crucial information.
In this article, you'll discover the advantages and drawbacks, historical background, and various applications of PETG 3D printer filament. Besides, at the end of the article, a pleasant bonus is waiting for you. Don't miss it 😉
Let's get started!
What is PETG Filament?
PETG, short for polyethylene terephthalate glycol, is a polyester-based thermoplastic that is often used in 3D printing because of its durability and ease of use. PETG filament is based on a modified form of PET plastic, which we usually know from food packaging. The classic example is disposable or reusable bottles for drinks.
However, PET in its original form does not have the properties required for 3D printing, as it is very brittle, for example. With the appropriate modification by binding glycol to the polymer chains, the flexibility improves and the impact strength increases. Only through this process does PET become the PETG from which filament can be made for 3D printing. In the meantime, printing with filaments made of PETG has become very widespread, as it is almost as easy to process as PLA, but the material properties are similar to ABS. PETG printing is therefore already multiply mentioned and recommended in many forums.
What are the ideal applications for PETG filament?
PETG filament is a good 3D material for printing technical parts that are exposed to higher temperatures or stronger mechanical stresses. For what, the use of PLA is no longer possible.
PETG 3d printer filament is slightly softer and more flexible, and therefore very impact resistant. In combination with its high tensile strength, it is ideally suited for 3D printing parts that require high mechanical resistance. The comparatively high UV and temperature resistance also make PETG filament an excellent choice for items that are to be used outdoors. Even at higher temperatures, such as inside cars on hot summer days, parts 3D printed with PETG filament are significantly more stable than those made from PLA.
Besides, PETG filament is also well suited for parts that require little or no post-processing. It is therefore hardly possible to smooth PETG in the field of 3D printing. Due to its high chemical resistance, it cannot be smoothed with solvents such as acetone after printing. PETG filament is also not well suited for sanding or subsequent varnishing. Therefore, try to design the parts in such a way that they require as little finishing work as possible. Due to the wide range of colours available, painting is usually no longer necessary.
How should PETG filament be stored correctly?
PETG 3D Filament is very sensitive to moisture. Therefore, it must be stored properly to maintain the quality of the material. PETG absorbs moisture from the air, which means it is hygroscopic. If the 3D filament is exposed to high humidity for a long time, the quality of the print as well as the mechanical properties will strongly deteriorate.
That's why PETG filaments should always be stored as dry as possible after printing. One possibility is to store the roll in the vacuum bag with desiccant in which it was delivered - preferably sealed with some tape. Another possibility is to use a filament drying box. It is helpful to remove moisture from PETG and extend its shelf life. If you do not have a drying box, PETG filament can also be dried for approx. 3-4 hours at a temperature of 60°C (CAUTION: maximum 65°C) in an oven with hot air function. To be safe, place a sheet of baking paper between the grid and the spool.
TIP: Learn more about how to storage and dry 3D Filament here.
3D Printing with PETG: What print and bed temperature should you use?
One reason why PETG filament has become a popular material for many 3D printing users is that the PETG 3D printing temperature is usually not much higher than PLA. This makes PETG an easy-to-print alternative for many desktop 3D printers, as it does not place particularly high additional demands on the hardware.
The ideal PETG printing temperature is between 220 °C and 250 °C, depending on the manufacturer. This means that PETG can be printed with almost all common printers and hotends.
Unlike PLA, PETG requires a heated print bed. The required setting for the 3D printing PETG temperature in the print bed is relatively low compared to other materials such as ABS or ASA and is usually between 70 °C and 80 °C. This is also a problem for most 3D printers. This is also no longer a problem for most 3D printer models.
Although PETG has a relatively low tendency to warp, printing in a closed, draught-free environment can be advantageous for very large components or in very cold ambient temperatures.
At what speed should you 3D print PETG?
PETG can best be printed at a speed between 40 mm/s and 60 mm/s. One of the material-related peculiarities when processing PETG is the pulling of threads, the so-called "stringing". This can be reduced by increasing the printing speed, but too high a printing speed may lead to a poor overall print result.
Therefore, the print speed of 60 mm/s should not be exceeded with conventional printers and hotends. Besides the print speed, however, there are some other parameters and settings with which one can significantly improve the print quality.
What are the best print settings for PETG filament?
When 3D printing with PETG, well-set settings (also known as retraction) are essential to ensure a clean print with this material. When referring to retraction, it usually involves two parameters: speed and distance. These are the two settings that should be paid the most attention to.
1. Retraction speed indicates how quickly the 3D printer's extruder pulls the filament back into the nozzle when moving between points without extruding material. For most 3D printers, a good retraction speed for PETG is around 25 mm/s.
2. Retraction distance indicates how far the 3D printer retracts the filament into the nozzle when moving from one point to another. The retraction settings can vary depending on the type of extruder installed in the printer. For a direct drive extruder, the retraction distance should be in the range of 2-4 mm. For a Bowden extruder, this value is larger and should be around 3-7 mm.
These two settings can vary from a filament manufacturer. 3D filament providers may also recommend specific settings for their respective materials. In case you get problems when printing PETG filament, adjust one of the two parameters to get better results.
Does PETG filament require cooling?
Technically speaking, PETG 3D printing filaments do not require a fan for printing. However, there are situations where different cooling settings can achieve certain effects or properties.
3D printing with PETG with a cooling fan results in a smoother and more aesthetically pleasing surface, but it reduces the adhesion between individual layers. Printing without cooling can significantly increase layer adhesion, resulting in better mechanical properties of the finished part.
Some cases where the use of part cooling is important and necessary are bridges and overhangs. In these areas, the material, when still warm, is unable to maintain its shape long enough to cool down. Using the cooling fan at around 70-80% of its maximum speed in these sections prevents sagging.
Cooling with a fan is also advantageous for thin wall thicknesses and short time intervals between applying each layer on top of each other. In such cases, the underlying layer may not have fully dried before the printer starts applying the next one. The fan speed should be set between 20-50% to reduce the cooling time of the layers.
At the beginning of the 3D print, cooling should be completely turned off to ensure good adhesion of the material to the print bed and proper bonding of the initial layers. These settings can be easily adjusted through slicing software, making the devices well-suited for PETG 3D printing.
What is the glass transition temperature for PETG Filament?
The glass transition temperature is the point at which a solid glass or polymer changes to a soft, rubbery to viscous state. For PETG 3D material, this is around 80°C. Unlike PLA filaments, whose glass transition temperature is around 60°C, PETG is an excellent choice for objects that must withstand higher temperatures and still be easy to print. For even higher application temperatures, ABS filaments is then recommended, where the glass transition temperature is around 100 °C to 110 °C.
Advantages and disadvantages of 3D printing with PETG
Surely, there are certain advantages of 3D printing with PETG filaments, similarly to its disadvantages. And you need to consider all of them when choosing the right material for 3D printing. Let's take a look at the advantages and disadvantages of PETG 3D printing.
Advantages of 3D printing with PETG
3D printing with PETG filament offers many advantages, which is why this material is becoming increasingly popular among 3D printing enthusiasts. PETG filament is easy to print, like PLA, but it possesses better properties similar to materials like ABS. Essentially, it combines the best characteristics from both worlds.
The biggest advantage of PETG filament is its ease of printability. Although it requires a slightly higher printing temperature compared to printing with PLA, it is still significantly lower than most other technical materials. It exhibits excellent first-layer adhesion to the print bed, and with a clean first layer, there will be no issues with warping even for larger print objects.
Printing with PETG filament is easily achievable on most common 3D printers, in case they have a direct drive extruder or a Bowden extruder. Almost all printers are suitable for 3D printing with PETG. The only aspect that may require more fine-tuning is adjusting the retraction distance for Bowden extruders. PETG 3D material is durable and strong in many aspects. It also has significantly higher temperature resistance than PLA.
PETG is slightly softer than many other plastics, which gives it greater flexibility, resulting in high impact resistance and excellent tensile strength for parts printed with PETG filaments. It is also resistant to UV radiation and chemicals, making it a versatile all-round material.
The surface of parts printed with PETG has a strong glossy finish, although many manufacturers offer variants with reduced gloss in their product range. The odor produced during printing is barely noticeable.
Disadvantages of 3D printing with PETG
Like everywhere, there are also some disadvantages when printing with PETG filaments. While the advantages outweigh many other 3D printing materials, it is still important to know the small downsides that come with using PETG.
As mentioned several times, one of the most common issues faced when 3D printing with PETG is stringing. This mainly depends on the printing settings, i.e. after finding the optimal parameters for the combination of 3D printer and material, one should be able to reduce stringing considerably.
PETG also tends to perform rather poorly with bridges and overhangs. It requires sufficient time to cool, which often causes bridges or overhangs of an object to begin to sag. The solution to this is to use a fan that cools strongly enough to allow the layers to set faster, but does not affect the overall layer adhesion of the print too much.
While good bed adhesion is usually considered a good property, with PETG it can actually be too good in some cases. If the nozzle is too close to the print bed, it can happen that objects adhere very strongly to the print bed or, in some cases, cannot even be completely detached from a PEI printing plate.
Troubleshooting for PETG 3D printing problems
1) Poor bed adhesion and warping
As mentioned earlier, PETG filament usually has a very good adhesion of the first layer to the print bed. Nevertheless, there are some factors that make it difficult for PETG to adhere to the print bed or cause the object to detach from the bed later in the printing process.
2) Uneven print bed
Like most 3D printing filaments, PETG does not adhere well to an uneven print bed. If the bed is not completely flat - also referred to as poorly "leveled" - the gap may be too large at some points on the part to be printed to make sufficient contact with the print bed and thus the first layer. If there are problems with warpage or peeling of the part to be printed, checking or leveling the printing plate should be the first step to solve the problem.
When leveling the print bed, especially when 3D printing with PETG filament, keep in mind that a little more distance is needed between the print nozzle, or "nozzle" and the build plate than with other materials. Otherwise, the object print can stick to the bed and damage the coating of the printing plate.
3) Dirty print bed
If the 3D printer's printing plate is not cleaned at regular intervals, it is likely that it will be covered with dirt, dust or deposits of prints. This will prevent the material from adhering sufficiently to the print bed. If the PETG material still warps despite a leveled bed and increased bed temperature, it should be cleaned thoroughly. Different types of print beds require different approaches to cleaning. Glass plates should be thoroughly wiped with a streak-free glass cleaner and a clean cloth. PEI build plate surfaces are best cleaned with isopropanol.
5) Too much cooling
If you use the fan when printing with PETG, the layers may cool down too quickly. PETG has a very low shrinkage rate compared to ABS or ASA, but it still contracts slightly during cooling. Cooling too quickly increases this shrinkage and thus warpage.
The easiest way to solve this problem is to turn off the cooling for the first few layers - either completely or adjust fan speed according to printing progress. This ensures that the fan does not directly affect the first layers, so they have a better chance of maintaining the temperature until the end of the print.
6) Cold print bed
Another possible reason for a poor adhesion to the print bed can be that the temperature of the print bed is too low. This causes the material to cool down faster and begin to warp and separate from the bed, usually around the edges.
To avoid this 3D printing problem, it is important to find out which print bed temperature is best suited for the particular printer and the PETG filament used. The optimum temperature can be found out with a series of test prints of the same object with a gradual increase in the bed temperature, preferably 5° C per print. It makes sense to start with the temperatures recommended by the manufacturers and continue testing from there.
7) Blobs and pimples
Blobs and pimples occur quite often when 3D printing PETG filaments and are usually caused by over-extrusion. Blobs usually occur when the printer has to stop for a moment to start the next layer, and a little extra material spills out of the nozzle onto the object. They can occur at any point in the layer when the printer tries to push out more material than necessary.
For the most part, finding the cause of this problem is not easy, as over-extrusion can be caused by a number of things. Possible solutions could be:
Lowering the extruder flow rate
Increasing the retraction settings
Lowering the die temperature
These pieces of advice can all help with blobs and spots. Often these settings need to be changed several times until the right setting is found for the machine.
8) Stringing
Stringing while 3D printing is one of the best known and most common problems when printing PETG filaments. A too high set printing temperature, the use of wrong retraction settings or a too low set feed speed can be possible causes for stringing. All of these parameters can be easily changed in the slicer software used, and should significantly reduce stringing if corrected correctly.
9) A printed item with PETG cannot be detached from the print bed
As already mentioned elsewhere, the good adhesive properties of PETG sometimes even lead to the fact that the printed items can no longer be detached from the print bed, or only partially. The most common reason for this is insufficient distance between the bed and the nozzle, which causes too much material to be pressed onto the bed. PETG requires slightly more layer distance than other materials, so when switching to PETG, the print bed should always be re-leveled to ensure that the distance is always sufficient.
To remove a stuck, cooled object, it usually helps to heat the temperature of the print bed back up to the recommended temperatures for PETG and then to loosen it with a scraper. Always take care about it in order not to damage the printing plate.
Recycled PETG: Can it print the same as conventional PETG filament?
For producing Nobufil recycled PETG, we take mostly production waste left from the manufacture of medical packaging films. Due to the high material requirements, this waste is an excellent raw material for the production of filaments for 3D printing, with which one can achieve the same printing results as if he/she would 3D print with conventional PETG filament.
In the production of the Nobufil PETG filament, the recycling of this production waste is done in-house on our own equipment. We continuously monitor the product quality along the entire value chain. This ensures that printability and material properties are no different than with non-recycled PETG filaments.
Here is a small video of how we produce recycled 3D filaments:
However, for better printing results, it is recommended to follow the printing settings that written on the Nobufil recycled PETG boxes.
Try it yourself! Use the discount code TRYPETG15 to get a 15% off on any PETG filament.
To sum it up, 3D printing with recycled PETG offers the same printing results as 3D printing with traditional PETG filament. Plus, it's your personal contribution to protecting the environment and conserving resources.
Conclusion
Well, now you know PETG filaments better. We hope that this article was useful for you and you learned a lot of new information.
Feel free to test the Nobufil recycled PETG 3D filaments using the discounted code TRYPETG15 at the checkout in our shop.
Have you already printed with PETG 3D printing filaments? What are your experiences? Let us know in the comments to this post.
Have fun with 3D printing!
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