Print speed, which determines how quickly the motors, and as a result, the extruder moves, is perhaps the most significant parameter for the 3D printing process to be successful due to the many factors it affects.
While printing speeds that are too low can cause many issues, such as stringing, oozing, and deformation of the print, to name a few, printing speeds that are way too high are no good either, causing problems such as lower print quality, ghosting, weak layers, and many more.
Due to its level of popularity as the second most popular filament on the market, and on the other hand, due to it not being as easy to print as PLA, getting the print speed correct with PETG, in particular, is one of the most common obstacles in the 3D printing community, bringing us to our question for today.
What is the optimal print speed for PETG?
We recommend a print speed value that falls in the range of 40 to 60 mm/s for 3D printing PETG to obtain the best print quality possible without increasing the print time way too much.
On the other hand, if the manufacturer of the PETG you use mentions a print speed value – the best course of action is to go with that value instead.
Moving forward, we will take a more detailed look at how you can find the optimal print speed for PETG, how it can change during the printing of some parts (such as bridges), and how different print speed values can affect the printing process.
What Is the Optimal Print Speed for PETG?
Even though we can consider configuring the print speed to be more straightforward compared to most other parameters, there is no denying that correctly configuring it is vital to the printing process.
The optimal print speed for printing PETG is between 40 and 60 millimeters per second, which isn’t too fast, but not too slow either.
To fine-tune the print speed value, we recommend starting with a value of 60 millimeters per second and going down in increments of 5 mm/s if you face any issues related to print quality until you find a number where there are no issues.
The logic behind this process is to ensure that you stay at the highest print speed possible where issues don’t happen, which will provide the highest amount of time efficiency possible.
How Does Print Speed Affect Printing with PETG?
Understanding how different print speeds while printing with PETG impact the printing process will come in quite handy for fine-tuning the value as optimally as possible.
First off, let’s start with how a print speed value that is too high would affect the PETG printing process.
If you use a print speed value that is way too high while printing with PETG, the main issues you will experience are poor layer adhesion and low print quality.
Poor layer adhesion, as you may predict, happens due to the layers not having enough time to cool down and form strong bonds with each other before more and more layers keep coming.
As a result of poor layer adhesion, the model becomes structurally weak and prone to physical damage such as cracking.
Low print quality can show itself in the form of under-extruded areas where the print lines become inconsistent (thinner than they should be), holes, gaps, and artifacts on the surface, also known as rippling; echoing, ringing, or ghosting.
Now, let’s take a look at the potential issues you will face if you print PETG with print speeds that are way too low than what’s optimal.
With a print speed that is too slow while printing PETG, you will most likely notice blobs, stringing, deformation on the print surface, and very long print times.
In a nutshell, when the nozzle takes too long the move, the molten plastic will start oozing out, causing the issue we know as blobbing, where blobs of plastic start appearing on the surface of the print.
With a model that contains a lot of empty space, stringing is the main problem, where strings of filament appear in the paths that the extruder took during the printing process.
Finally, as you should always attend to your 3D printer while the printing process takes place, too long print times can quickly become a time sink, making achieving shorter print times rather significant.
Bottom line, due to both too high and too low print speeds being problematic, finding the optimal print speed value while printing with PETG is one of the cornerstones for a successful printing process and final product.
Can You Print Fast with PETG?
The word “fast” is subjective, but we can say that PETG is one of the filament types that benefit from print speeds on the lower side in general, primarily due to hardware limitations.
While it’s technically possible to print PETG as fast as PLA, one of the filament types that we print at the highest speeds, the reason behind the print speed recommendation for printing PETG being much lower than PLA is related to the printer hardware.
In a nutshell, PETG requires more hotend power (considering that PETG is denser and requires a higher print temperature) for the printer to melt and bond it successfully, where most stock extruders fall short when you introduce higher printing speeds.
As a result, printing PETG with these stock extruders yields better results when we use lower print speeds, which is the more feasible option as opposed to replacing the extruder with a better one unless you really need the higher print speed.
While experimentation is necessary for fine-tuning, just as many other things in 3D printing, we can say that print speed is one of the parameters that you can usually correctly configure by following the guidelines.
To quickly recap, a value between 40 and 60 millimeters per second is optimal for printing PETG as fast as possible while avoiding issues related to print speed, such as weak layer adhesion and artifacts on the print surface.
Unless the manufacturer states the exact print speed value you should use for printing the PETG you have – experimentation is vital to find the number that works best for your printer and filament.
We hope that this guide has been helpful for you to configure your print speed for PETG as smoothly as possible.
Mike started his 3D printing journey with the Anet A8 when it first came out back in 2017, and has been obsessed with 3D printers ever since. Nowadays, he primarily uses his Ender 3 to print functional parts that make his life more convenient whenever possible.