While solving problems related to the 3D printing process can be tedious for some 3D printing enthusiasts, it’s a learning experience that is a part of the journey for others, and after all, since issues are a part of 3D printing that we can’t avoid, making the most of them is all we can do.
Especially putting into consideration that problems in 3D printing can appear on many different fronts, with both mechanical hardware, electronic hardware, and software all coming together, there is usually a lot to learn from any troubleshooting process, regardless of how severe the problem is.
Today, we will be discussing one of the 3D printing issues that we can consider non-critical in the sense that it does not cause a print failure, yet still requires solving in most cases due to its effects on how the model looks from the outside, where the infill pattern of the model ends up becoming visible through the walls.
So, what can cause the infill pattern of your 3D printed model to become visible through the model’s walls?
There are three primary reasons that can cause the infill pattern to become visible through the walls of the model you have printed; a too high infill overlap value, a too low wall (shell) thickness value, and the activation of the infill before walls feature that you can find specifically in Cura.
In the upcoming sections, we will dive deeper into the factors that can cause the infill to show through the walls of your 3D printed model, discuss the potential solutions that can help to resolve the problem, and finally, take a quick look at a similar scenario, where the infill ends showing through the top layer instead of the walls.
What Can Cause Infill to Show Through the Walls of Your 3D Print?
The infill showing through the walls of your 3D printer is something you definitely want to avoid since the pattern of the infill being visible from the outside will cause your 3D printed model to look aesthetically displeasing.
As there are three main culprits behind the issue of infill showing through the walls of a 3D printed model, we will be analyzing each culprit in detail in this section to help you pinpoint the one that’s causing the problem in your case.
High Infill Overlap
The infill overlap parameter determines the length (or percentage) of infill that will overlay with the walls of the 3D model, where utilizing an increased value brings the primary advantage of improving the strength of adhesion between the infill and the walls.
When the infill overlap value is set to a value that is too high, the infill ends up pushing more into the walls and, as a result, gets closer to the surface of the 3D printed model, which can cause it to become visible through the walls.
As lowering it all the way would also cause issues in the front of adhesion strength between walls and infill, finding a balanced value is vital for a successful print.
Low Wall (Shell) Thickness
The wall thickness parameter determines how thick the walls of the model will be, and as the thickness increases, so does the distance between the surface and the infill.
When the wall (shell) thickness is set to a value that is too low, the distance between the surface and the infill of the 3D printed model will be too little due to the walls being way too thin, causing the infill to show itself through the walls.
Aside from the problem of infill showing through the walls, a way too low wall thickness value can also cause issues such as the model having reduced strength.
Infill Before Walls
Infill before walls is a Cura feature that reverses the order of printing for the walls and the infill, causing the 3D printer to print the infill first and the walls afterward, which prevents the walls from deforming as they get support from the infill.
On the other hand, when the infill before walls feature is active, the infill ends up pushing into the walls while the walls are in their melted state, causing the walls to deform, which can end up with the infill showing from the surface.
As the infill before walls is a feature that you should consider utilizing on a case-by-case basis, there is no right or wrong here.
How to Fix the Issue of Infill Showing Through the Walls?
Since a few distinct factors can cause the infill to show through the walls, unless you are sure which exact one is causing the problem in your case, you will need to go through a few potential solutions until you find the one that works for you.
Below are the solutions we recommend applying to fix the issue of infill showing through the walls of your 3D printed model, which correspond to the three main factors we have mentioned earlier:
- Reduce the Infill Overlap value – Reducing the infill overlap value will reduce the infill pushing into the walls, decreasing the chance that the infill becomes visible through the wall due to the increased distance between the infill and the surface. We recommend starting with a 30% infill overlap value and adjusting in 5% increments later.
- Increase the Wall (Shell) Thickness value – Increasing the wall thickness value will enlarge the area between the infill and the surface of your 3D model, making it less likely for the infill to make itself visible from the outside. We would recommend starting with a wall thickness value that falls in the range of 0.8 mm to 1.6 mm, and testing to optimize further.
- Deactivate the Infill Before Walls feature – Deactivating the infill before walls feature will cause the walls to be printed before the infill, giving them enough time to solidify and gain structural integrity before the infill comes. This way, the infill won’t be able to push into the walls and make themselves visible from the outside.
In most cases, going through these three solutions should prevent the infill from being visible through the walls of your 3D model.
Infill Showing Through the Top Layer – What to Do?
The infill showing through the top layer is a very similar problem to the infill showing through the walls, as in either scenario, the infill pattern ends up becoming visible from the outside when it should entirely be contained inside the 3D printed model instead.
In the specific case of the infill showing through the top layer of the model, the most likely culprits are a high infill overlap value and a low top layer thickness value, with each culprit being capable of causing the problem at hand individually.
While the optimal top layer thickness varies heavily on a case-by-case basis, we would recommend going with at least 0.8 mm of thickness to eliminate the problem of the infill showing through the top layer and increasing it even further if necessary.
For infill overlap, we recommend starting with a value of 30%. While it’s best to keep this value as low as possible to prevent large amounts of plastic overlapping, feel free to increase it if you’re having problems with the walls and the infill bonding with each other.
As there isn’t much else that can be behind this problem, applying the solutions above should do the job and prevent the infill from showing again.
The infill showing through the walls is a problem that can get pretty irritating even though it does not technically cause the print to fail or damage it in any way, especially if the models you are 3D printing are intended to serve aesthetic purposes.
To quickly recap, let’s take a final look at the factors that can cause the infill to show through the walls of the 3D model you have printed, which are:
- A high Infill Overlap value
- A low Wall (Shell) Thickness value
- Activating the Infill Before Walls feature
As all of the factors that may be the culprit can easily be eliminated without needing to delve into areas that are technically complex, solving the problem should, in most cases, be a straightforward task that won’t require a lot of your time.
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.