What Causes ABS Layer Separation in 3D Printing? (How to Fix?)

Adhesion issues are, without a doubt, some of the most prominent problems in 3D printing due to their capability of completely ruining prints and rendering them unusable, whether it’s a bed adhesion issue or a layer adhesion issue.

Combined with the fact that so many different factors can cause such issues, it can be a real pickle to find the root cause and apply the suitable fix in most instances, turning the 3D printing process into a complete nightmare at times.

Today, our topic is the commonly encountered issue of layer separation while printing with ABS filament, a problem where the layers of the object end up peeling off of each other due to the adhesion strength between the layers not being strong enough to hold the model together.

So, what causes ABS layer separation in 3D printing?

Here are the things that can cause layer separation while printing with ABS filament:

  • Too high print speed
  • Too low print temperature
  • Too much cooling
  • Too high layer height
  • Too low flow rate
  • Clogged nozzle
  • Moist filament

In the upcoming sections, we will analyze the issue of ABS layer separation in more detail, find out how to improve the layer adhesion to fix the layer separation problem and look at the signs that indicate you may be experiencing ABS layer separation.

What Causes ABS Layer Separation in 3D Printing?

As there are a fair few factors that can be behind the issue of layer separation while 3D printing with ABS filament, individually going through these factors will help us understand the problem more clearly.

Below, we have listed all the factors that can cause ABS layer separation and the detailed explanations for how these factors can cause the problem:

  • Print speed too high – When the print speed is way too high, there is a chance that the printer will keep printing the upcoming layers without giving the previous layers enough time to form strong bonds with each other, which will cause layer separation.
  • Print temperature too low – The ABS filament won’t reach the heat level that allows it to correctly melt with a too low nozzle temperature value, causing the plastic to solidify before the layers can form strong bonds with each other.
  • Cooling fan speed too high – A cooling fan directly blowing on the layers will prevent the layers from having enough time to form bonds before solidifying, and ABS plastic, in particular, is especially prone to layer separation in such a scenario.
  • Layer height too high – When the layers are larger than optimal, it will be harder for them to bond due to a large amount of space in between, which can cause the layers to separate from one another.
  • Flow rate too low – A low flow rate means that your printer is under-extruding, which can cause layer separation due to there not being enough plastic for the layers to merge strongly enough to each other.
  • Nozzle clogged – A partially clogged nozzle will cause under-extrusion, similar to a low flow rate value, which once again will prevent the layers from having enough plastic to bond successfully.
  • Filament absorbed moisture – There is no denying that a moist spool of ABS filament will cause all sorts of issues for your prints, and layer separation is one of the common problems that occur as a result.

How to Improve ABS Layer Adhesion and Fix Layer Separation?

Fixing the ABS layer separation issue is mainly about increasing the adhesion strength between layers of plastic, which mostly comes down to ensuring that the print configuration is optimized.

Below are the print settings we recommend re-configuring to improve the layer adhesion while printing with ABS and fix the issue of layer separation:

  • Decrease the print speed. Since keeping the print speed as high as possible is optimal, we recommend going down in small increments of 5-10 millimeters per second until you notice a change or until the print speed becomes slower than acceptable.
  • Increase the print temperature. While the best thing you can do is follow the manufacturer’s recommendations for setting the print temperature, it will be helpful to stay on the higher end of this range to eliminate the possibility of a temperature-related problem. Increasing the temperature in increments of 5-10 degrees Celsius while staying in the range of the manufacturer’s recommendations is a suitable way to go about this.
  • Decrease the part cooling fan speed. As ABS is pretty sensitive to cooling, pulling the cooling fan speed down to 0% is the best way to ensure that the cooling fan isn’t the culprit behind the layer separation issue you’re facing. If you prefer not to go all the way to 0% at once, a reduction in 5-10% increments should also work.
  • Decrease the layer height value. As the optimal layer height depends on the size of the nozzle, we recommend using a layer height value that falls between 25% and 75% of the nozzle size. Going down in small increments (like 0.04 mm for a 0.4 mm nozzle) will yield the best results.
  • Increase the flow rate value. Since the flow rate is a delicate setting that can easily cause over-extrusion, we recommend increasing your flow rate value in increments of 3-5% until you notice problems related to over-extrusion start appearing.

While re-configuring the print settings should solve the problem more often than not, we have also previously mentioned that physical factors can also be the culprit at times.

Here are the things we recommend doing to fix the layer separation issue while printing with ABS filament if re-configuring the print settings did not help:

  • Thoroughly clean the nozzle. While you should be able to get rid of any partial clogs with a wire brush or a needle, performing a cold pull with a cleaning filament should yield the best results in most cases.
  • Dry or replace the filament you’re using. Even though replacing the filament is the best way to ensure that your problem isn’t filament-related, ensuring that it’s dry and free of moisture should also do the job.

How to Identify ABS Layer Separation?

If you suspect that the objects you have printed with ABS filament may be suffering from layer separation but aren’t entirely sure, here are some signs that suggest layer separation is indeed the problem.

If the models you print with ABS filament are experiencing the issue of layer separation, the first thing you will notice are cracks between the layers of your print due to the layers not sticking to each other correctly.

While in severe cases, the cracks will be outright visible, in milder cases, you may not notice the weakness between the layers unless you apply force, which will immediately cause the model to crack as the bonds between the layers won’t hold.

Since the delamination of the layers essentially means that the model isn’t whole, we highly recommend checking models that you print for functional purposes for signs of this problem before usage.

Wrapping Up

Dealing with the problem of layer separation can definitely be irritating due to the extent of the damage it causes to your prints and the effort required to solve it due to the many factors that can be the culprit behind the issue.

To quickly recap, let’s quickly go through the factors that can cause ABS layer separation, which is as follows; too high print speed, too low print temperature, too much cooling, too high layer height, too low flow rate, a clogged nozzle, and a wet spool of ABS filament.

While in most cases, factors related to the print settings are the culprit, keeping in mind that physical factors can also cause the layer separation issue is vital to ensure that you solve the problem.

Happy printing!