A little about PETG
PETG is a common 3D printing filament. Polyethylene Terephthalate Glycol can be readily found in some mechanical parts and especially in water or drink bottles because of it’s waterproof nature and food safe abilities. You may have also heard about PET, the original PETG. The difference is the glycol (which is where the G comes from), which is what makes PETG near transparent, making it very effective at showing you water levels inside a bottle.
Positives and negatives of PETG
You’ll find that PETG has lots of strengths. The material prints nicely and looks glossy, which is mostly a good thing even for hidden mechanical parts - but it does make an attractive bottle or container. Compared to somewhat similar ABS, PETG is cheaper and is less likely to experience warping, which is part of the reason why it is used on the process of making many, many bottles.
PETG also does not bridge well. When printing, the support structure for your print might not use PETG. Some might also find the tiny strings of plastic produced at the edges of a print with PETG to be kind of annoying - though they are easily removed.
How do you set up a CURA printer to best print with PETG?
Let’s go over a few settings that will help make your PETG print more likely to succeed, look good, and reduce the chances that you’ll have to intervene afterward.
One quick note: the common temperature measurement for 3D printers is not in American standardized Fahrenheit, but Celsius. All temperatures listed below are in Celsius or °
The nozzle temperature should be set to about 235°. The right nozzle temperature allows PETG to flow properly and melt at the right speed. If you do choose to make changes to the temperature based on poor performance or want different performance, we suggest you make small changes because even small changes make a big difference in temperature.
This is the temperature of the heated bed you’ll want when printing PETG. A heated bed is designed to allow the melted and printed filament to have a warmer place to slowly reach the desired room temperature. You’ll prevent warping better this day. The bed temperature should be set to 70°.
Note that for smaller PETG prints, you won’t need a bed as it cools down efficiently on its own.
The recommended print speed for PETG on a CURA 3D printer is around 40mm per second. 40mm is a little on the slower end of the printing process when many 3D printers can print at speeds around 60mm per second or more. Slower is better for PETG. The stock setting on a CURA printer is around 50mm per second, which is closer. You can readily adjust this print speed if you find that you want to shave off some time while taking small risks with getting blobs or stretching.
If your PETG print is especially detailed, we recommend even slower. If quality and detail aren’t all that important, go faster.
Initial Layer Print Speed
The initial layer provides a solid foundation for whatever you are printing with PETG. The lower speed lets your printer make sure you get a good first layer so that later adhesion comes easier.
Travel speed refers to how fast the nozzle and extruder move when the 3D printer isn’t printing - more literally when the the extruder is moving to the next spot to start printing. A low travel speed can result in smudge and stringing as the extruder can continue to melt PETG as it comes out. We recommend setting this to 120 mm per second.
With a somewhat fast travel speed and a low print speed, we recommend a longer retraction distance of 6mm for PETG on CURA. Since PETG can string, the retraction speed needs to be faster.
There is a difference with Bowden and Direct Drive printers here, too. A direct drive should be around 2 to 3mm.
This describes how quickly your PETG retractions back into the exturder when not printing. A fast retraction speed reduces the chances of having the filament dribble and string. Too quick and the filament might separate from the hot nozzle.
We recommend starting at 25mm per second and moving faster if the print quality is retained. 35 to 40mm isn’t out of the question. Test carefully!
Cooling is an understated part of 3D printing because it can change the quality of the final print a lot. We recommend leaving your fan at about 50% because PETG cools efficiently without more power, and because faster temperature changes can accidentally encourage warping.
Less cooling also helps PETG remain stronger as it adheres better to itself. If you can leave the fan off, you’ll get the most sturdy possible product.
Build plate adhesion
PETG is rather sticky. A brim or raft setting works best. Glossy PETG will remove from the wide, deep base that a raft produces. The brim setting is good too because it sets a smaller base than raft. If you have an issue removing your print after raft, switch to brim.
How do I find settings with CURA?
Settings are ground under material-specific menus. You should be able to click on “Material” on the right side, then “Generic” then “PETG”.
We certainly recommend the idea of changing any necessary settings based on the print quality you are getting or any problems you are having.
How do I store PETG for best use with CURA?
PETG readily absorbs water prior to being extruded. You’ll want to keep PETG in an airtight, dry container in a non-humid room. In other words, if the weather is humid, you don’t want to leave the windows open!
Does CURA provide a guide?
CURA generally does a good job of explaining, in just a few words, what a change will do to a print. With that said, CURA has no idea what you are printing or your quality expectations, so feel free to explore and see what they mean by high quality.