Pillowing in 3D Printing: Causes and Solution

The use of 3D printing technology has several drawbacks and problems for different reasons. Thus, caution is necessary to achieve the ideal 3D printing results. To get accurate outcomes, the problem should be identified as soon as possible. Next, it is necessary to address the many causes of this issue. Finally, a workable solution must be identified, and the required steps must be taken.

 

When it comes to the "pillowing" issue, a lot of people become irritated since, with 3D printing services, pillowing becomes apparent or observable after half of the printing process is complete. This may result in a waste of time, effort, and resources. Generally speaking, pillowing happens as the top layer of the 3D print cools.

 

3D Printing Pillowing: What is it?

A common 3D printing issue called "pillowing" is the uneven surface of the top layer. This characteristic may seem as a patchwork of tiny lumps, an extremely uneven surface, or even tiny holes and gaps.

 

Pillowing is especially annoying because it only appears when a print is almost finished. You would have used quite a lot of filament and time by the time the top layer was printed. It results in a great deal of waste and necessitates a project restart.

 

Using any kind of 3D printer or filament will not prevent pillowing. The bright side of this is that fancy tools or accessories are not needed to solve it either.

 

When starting a 3D printing project, it is preferable to avoid pillowing because of the potential consequences. You'll save a tonne of filament, time, and effort.

 

What are the Causes of Pillowing?

The fact that pillowing only appears during the printing of the top layer, or when the print is always finished, makes it a particularly annoying issue. Pillowing is an issue worth expecting and understanding so you may take the necessary safeguards to prevent wasting so many hours of effort. Anyway, what exactly causes pillowing?

 

Filaments that Melt Quickly:

The performance of thermoplastic printing filament differs from that of 3D printers. They have varying print temperatures, and those that have a propensity to warp are more likely to show signs of pillowing.

 

As the filament cools, the top layer begins to warp. The material is drawn towards the infill pattern right beneath the top layer by the stress caused by thermal contraction. Insufficient strength in the upper layer will result in noticeable holes or an uneven surface.

 

Improper cooling:

Cooling Process: Image Source: ecoreprap.com

If pillowing persists, then cooling must be enhanced. Before anything else, make sure the cooling fans are turned on and rotating during the printing of the upper layers. If so, it's possible that the fans aren't set up to properly chill your prints. To address this issue, a desk fan or something similar would be helpful, and there are lots of mods available internet.

 

The first thing you should do is switch on the fans if they are off during printing. Make sure the cooling fans in the slicer are turned on. You will have to manually edit the G-code if your slicers do not offer this option. You should be able to activate the cooling fans with the command M106.

 

Insufficient Supporting Material:

Sometimes the filament material falls through the gaps, causing holes to form in the top layer.

 

The filament with poor bridging performance will most likely experience pillowing because there is insufficient infill to support the top layer.

 

Soft Filaments:

Soft Filament: Image Source: ecoreprap.com

Soft filament is another kind of filament that has the potential to increase the issue. These can cause issues with the top layer of the 3D printers and are also very prone to pillowing.

 

When these succumb to pillowing, the entire print is readily destroyed. But there are many approaches of dealing with this. One thing you may try is using a greater infill rate. 

 

3D Pillowing Solutions

To get rid of pillowing in 3D printing services, a wide range of options are available.

 

Utilising a thicker top layer:

Thicker top layer: Image Source: pick3dprinter.com

Using a thicker top layer, which is designed to give the surface strength and robustness, is the most effective technique to reinforce the uppermost layer. It should also help with pillowing, as it is also the case with warping, and it is also the easiest way to solve the issue.

 

Just make the very bottom layer thicker to prevent any potential warping. In this manner, the increased mechanical resistance against the thermal stress brought on by filament cooling can be ensured. 

 

You can both quit pillowing as well. In this scenario, the top layer's thickness is increased to help it retain the deformation caused by the material cooling.

 

However, in order to properly avoid pillowing, how thick must the top layer be? You may use your simple method to get the ideal layer height:

 

The thickness of the top layer should be roughly five to six times that of the lower layers. This will not function if the normal layer height is configured to be thin.

 

The height of the top layer should be increased more than six times. Modify the settings for the top layer. Experiment with different parameters to see what your print object responds to the best.

 

Through Raising the Infill Proportion:

As this article has already pointed out, the issue arises when the top layer's weight becomes unsustainable and moves into the gaps between the infill.

 

It makes its way through the openings left by the infill structure, increasing the likelihood of pillowing in these prints.

 

According to online guidelines, 12% of infill is sufficient to print the models without creating difficulties when the model passes through the infill gaps.

 

To avoid pillowing, you must, however, set the infill percentage to 25% when experiencing pillowing problems.

 

Even though it's a simple remedy, makers save this for last when they can't figure out how to address pillowing. Without any difficulty, the slicer program allows you to adjust the parameters. But it comes with its own set of drawbacks.

 

Both the quantity of filament needed for the print and the printing time are increasing. Therefore, the technique might not be very popular with people whose goals are high speed or cost savings by using as little filament as feasible.

 

Enhance Your Cooling:

Making the most of the cooling of the top layer of your product is one of the easiest ways to avoid pillowing. This motion can quickly acquire stiffness and strength before buckling or warping causes it to become distorted.

 

Sometimes pillowing can occur even with the cooling fan set to its highest setting. In the event that you encounter such circumstances, a basic desk fan may prove beneficial. A well-ventilated room is essential for printing since the cool, fresh air from the outside helps hasten the filament's cooling process.

 

Reduce the Printing Temperature:

Why heat the filament initially if cooling is the issue? A good method is to lower the printing temperature for your print's top layer. By easing the filament's development of rigidity sooner, it aids in reducing thermal stress during cooling.

 

As previously said, lowering the printing temperature and speed go hand in hand. It is important to change both of these factors at the same time to avoid extrusion issues.

 

Take care to only do this once printing of the top layer has begun. Lowering the printing temperature usually results in a decrease in layer adhesion. But in the top layer of a print, layer adhesion is no longer as crucial.

 

Expanding the distance between the print head and the building plate:

The top layer can cool down and stop pillowing more quickly if the space between the print head and the construction board is increased.

 

This is usually caused by an extremely high nozzle temperature, which also causes an exaggeration of the near temperature. On the other hand, the ambient temperature stays the same if you remove the print head from the building platform significantly.

 

You should be familiar with using a 3D printer to some extent as this step could result in problems similar to poor layer adhesion in 3D printing services if it is not done correctly.

 

Best 3D Printing Software: SelfCAD

SelfCAD is among the greatest 3D design and printing software for creating both simple and complex objects. It is easy to use for people of all skill levels and features a straightforward user interface. You can utilise the intriguing freehand drawing and sketching tools that are included, along with other modification tools, to start from zero while creating your creations. In order to precisely and creatively shape, change, and refine 3D objects, there are also a lot of 3D sculpting brushes available.

 

The program's online slicer makes it easier to prepare models for 3D printing and works with the majority of popular FDM 3D printers. Because the software is cloud-based, users can access it on any device and from any location. Additionally, SelfCAD is available for download, allowing for offline use. These two versions are synchronised with each other.

 

Conclusion

Pillowing isn't really one of the trickiest 3D printing difficulties. Nevertheless, because pillowing occurs right before a printing work is done, it can be very discouraging.

 

Thankfully, there are also comparatively easy fixes for pillowing. Just prepare to dive right in when your print gets closer to the outermost layer. It could require some trial and error, but as long as you get the basics of filament behaviour during cooling, you should be able to solve the problem rather easily.