Why Is My PETG Filament Warping & How to Fix It? (Solved)

While it’s common knowledge that each filament type comes with advantages and disadvantages for the final product, a vital point to also consider is that you will also need different slicer settings for different filament types.

Since most beginner 3D printing enthusiasts who switch from PLA for the PETG for the first time aren’t aware of this, they face plenty of problems with factors such as layer adhesion, low print quality, warping, and many others.

We have noticed that many members in the community are facing issues related to warping (also known as curling or corner lifting) while printing with PETG in particular, which will be our topic today.

So, what can cause PETG filament to warp?

PETG filament can warp due to the following reasons:

  • Print bed not level / Z offset not correct
  • Nozzle temperature too high
  • Bed temperature too low
  • Print speed too high
  • Cooling fan speed too high
  • Filament not entirely dry
  • Build surface not clean

As the way of solving the PETG warping issue depends on the reason that’s causing it, the first order of business to fix to issue is to find the culprit.

Moving forward, we will analyze each of the possible reasons that can be causing the issue and look at the other symptoms they would also cause, which will help us pinpoint the root cause.

Why Is My PETG Filament Warping?

Unfortunately, PETG can warp due to many factors, making it impossible for us to tell you what’s causing the issue you’re facing in particular.

In this section, we will be listing all of the possible reasons that can cause PETG to warp with detailed explanations, and hopefully, help you find the one that’s giving you trouble.

Print Bed Not Level / Z Offset Not Correct

While print bed not being level and Z offset not being correct are two different issues, both can cause warping in a similar way.

When the bed is not level; or the Z offset is not correct, certain areas of the first layer of the model end up being squished due to the distance between the nozzle and the print bed not being consistent.

This inconsistency usually presents itself in the form of:

  • Warping
  • Weak bed adhesion
  • Under-extrusion in first-layer (usually with noticeable gaps)
  • Inconsistencies in filament width and height
  • Elephant’s foot

We highly recommend purchasing an auto bed leveling sensor (such as BLtouch) to eliminate issues related to bed leveling and Z offset, as these issues can easily plague your prints without you even noticing.

The best course of action to level your printer’s bed and calibrate its Z offset is to refer to the documentation of the firmware you’re using, where you can read about the process in detail.

Nozzle Temperature Too High

Nozzle temperature being too high is another one of the most common reasons behind PETG filament warping.

As warping happens due to the differences in temperature between layers, a nozzle temperature that is too high can easily cause the model to warp, especially at the lower layers.

Alongside warping, a nozzle temperature that is too high would also cause the signs below:

  • Stringing
  • Drooping
  • Blobbing / Oozing
  • Artifacts
  • Model sticking to the print bed

While the optimal nozzle temperature can show differences between manufacturers, you can use a nozzle temperature of 220 to 260 degrees for printing PETG and experiment to find the optimal value if the manufacturer does not state it.

Bed Temperature Too Low

Similar to a high nozzle temperature, a low bed temperature is another factor that causes PETG warping.

Alongside causing bed adhesion issues that also play a role, a low bed temperature increases the temperature gap between the layers of the model, which is the main reason for warping.

As a bed temperature that is too low will immediately cause glaring bed adhesion issues, you can quickly pinpoint the problem in this scenario.

We recommend starting with a bed temperature between 70 and 80 degrees Celsius and experimenting further to find the optimal value for the filament you use unless the manufacturer states the exact bed temperature you should be using.

Print Speed Too High

A high print speed can also be the culprit behind warping issues with PETG filament.

When the print speed is too high, the model doesn’t get enough time to cool down evenly, which can cause warping as a result. Lowering the print speed in conjunction with nozzle temperature is often a great way to solve warping issues.

Alongside warping, here are some of the other symptoms a print speed that is too high can cause:

  • Under-extrusion
  • Ringing
  • Weak layer adhesion

We recommend starting with a print speed between 40 mm/s and 60 mm/s and experimenting to find the optimal value.

As higher print speeds are favorable, the best course of action is to start with 60 mm/s and reduce the value in 5 mm/s increments until warping isn’t an issue anymore.

Cooling Fan Speed Too High

As the cooling fan speed affects the object’s temperature, an incorrectly set fan speed can also cause it to warp.

When the cooling fan speed is too high, the first layer of the print will end up cooling way too fast. As a result, the adhesion between the bed and the model will be weak, causing warping.

Aside from bed adhesion and warping issues, a cooling fan speed that is too high can also create adhesion issues between layers due to the layers cooling down too quickly.

To eliminate issues related to the cooling fan speed, we recommend printing with a fan speed of 0% during the first few layers to ensure that the bed adhesion is as optimal as possible.

As most slicers allow you to set different fan speeds for layers, you can gradually increase the fan speed as you move up in layers moving forward.

Filament Not Entirely Dry

A factor that isn’t mentioned too commonly is filament not being dry, which can easily cause PETG to warp due to the moisture content.

Here are some of the things you may experience while printing with a filament that has absorbed moisture:

  • Cracking sounds during the printing process
  • Steam coming out of the printhead
  • Low print quality (hairy, fuzzy prints)
  • Weak layer adhesion
  • Inconsistencies in extrusion

Upon noticing any of these signs, we recommend stopping the printing process immediately and drying the filament before using it again.

While the optimal way to dry PETG filament is with a filament dryer, there are also alternative ways to do it with household items such as a food dehydrator or an oven.

Build Surface Not Clean

Finally, a dirty print surface can cause warping through the bed adhesion issues it creates.

When the build surface is not clean, PETG will have issues sticking to the bed, and as a result, your model will warp.

Poor bed adhesion and warping go hand-in-hand no matter what causes it, and a dirty build surface is no exception to the rule.

In this case, we recommend thoroughly cleaning the build surface with isopropyl alcohol and refraining from touching the build plate or placing items on it to ensure that it stays clean.

How to Prevent Warping in PETG Filament?

If you are facing issues even after ensuring that you have configured everything correctly, fear not, as adjusting the print settings isn’t the only thing you can do to prevent warping in PETG.

We only recommend applying these solutions after you have made sure that you have configured your printer settings correctly.

Add a Raft or Brim

Rafts and brims are extra layers that you can add to the bottom of your print. While a brim is an outline, a raft covers the whole area at the base of the model you’re printing.

Adding a raft or a brim to the model allows it to have a larger surface area that connects it to the print bed, which is a quick way of eliminating bed adhesion and warping-related issues.

As rafts and brims are excess materials, you will need to remove them after the printing process is over.

Use an Enclosure

An enclosure is a box that covers the model during the printing process, which comes in handy to regulate the temperature and protect the model from drafts that can harm it.

When you print in an enclosure, the temperature of the printing environment is much more controlled and consistent, which allows the model to cool down as evenly as possible.

As the primary cause of warping is uneven cooling, an enclosure can solve the issue surprisingly quickly.

Use Adhesives on the Build Plate

Poor bed adhesion is a factor that causes warping, and in some cases, it’s not very possible to solve it by only cleaning the build plate.

By using adhesives on the build plate, such as a glue stick, painter’s tape, or hair spray, you can effortlessly strengthen the adhesion between the bed and the model, which can be helpful to eliminate warping.

Please note that this solution will only work if the source of the warping is poor bed adhesion.

Wrapping Up

Warping is a pretty common issue when printing with PETG filament – but also an easy one to solve.

Ensuring that your PETG doesn’t warp mostly comes down to configuring the settings of your slicer and your printer correctly, as using the settings you’ve been using for PLA (or any other filament type) won’t work optimally with PETG.

On the other hand, if you’re still facing issues after confirming that all the settings are correct, extra measures such as using an enclosure, printing a brim, or applying adhesive to the bed can also be helpful.

We hope that this article has been helpful in fixing the warping issue, and we will see you next time!