Cura is one of the most popular slicing applications for FDM 3D printing in the world.
Part of its popularity stems from the fact that it is completely free. The slicer also offers wide range of printing parameters, model compatibly, great usability and advanced support setting.
Today, we’ll discuss the functionality of infill patterns and which one to choose for your model.
So, what are the best infill patterns that you should use in Cura?
While different patterns are best for different roles, the best all-rounder option is tri-hexagonal. It offers the best balance between strength, material usage, printing time, and load-bearing capacity.
What are Infill Patterns in 3D Printing?
To understand infill patterns, we need to understand 3D printing as a whole.
An FDM 3D printer extrudes and deposits filaments in layers until you get a solid 3D object. Thanks to gravity, we cannot print the roof before the house.
In 3D printing, you have to work in layers.
There is a small issue with what goes on inside the cavity of your 3D prints, the places that will never see the light of day.
The interior is usually a combination of plastic and space, and how you tackle this question is a subject of fierce debate to this day.
You also need to consider the geometrical structure of the internal plastic.
These patterns are necessary to maintain the structural integrity of your projects.
How you choose to fill the void inside your projects is up to you. You can go for grids, triangles, and other 2D and 3D patterns.
To test different infill patterns, you can also use the temperature tower to print different blocks with different kinds of patterns and find out their strengths.
The patterns you choose affect the material usage, strength, flexibility, and weight.
14 Best Cura Infill Patterns Based on Strength
Because geometries are not all strong, the infill pattern you choose affects part strength.
Do take this ranking with a grain of salt.
For instance, while the gyroid pattern ranks higher on my list, it does not handle compressive force nearly as well as the cubic/cubic3D pattern, for example.
It is the triangle pattern except the lines are offset a bit.
What happens is that instead of getting a grid of triangles of equal size, you get small triangles and hexagons instead.
This is arguably the strongest pattern you can get in Cura, at least for forces applied in any horizontal direction.
This infill pattern is very strong because it involves wavy lines in alternating directions.
It is strong in all directions without being stiff. A lot of people love the gyroid pattern because it also looks beautiful, especially when you use transparent filaments because you can see the internal geometry.
One downside to this pattern is that it is algorithmically complex, so slicing the 3D model in Cura will take longer than other patterns.
The grid pattern is very similar to the line pattern.
One notable difference is how the printer lays down the line. In the lines pattern, the printer only lays down lines in one direction, putting perpendicular lines in layers.
In the grid pattern, the lines go in two directions, giving it a fair amount of strength.
It is one of the strongest infill patterns in Cura, at least if you want to apply load horizontally along the XY axis.
Instead of filling your project with simple grids, this pattern involves the use of triangles. It is very strong in every horizontal direction, with the interruption of flow at intersections being the main drawback.
Lines pattern is only strong when you orient the load properly.
It will fail rather quickly if it has to withstand loads in more than one direction.
What it has going for it is the fact that it uses minimum material, making it suitable for decorative models and other visual projects.
Using this pattern, your printer will dispense filaments unidirectional lines at each layer, switching up directions by 90 degrees when it gets to the next layer.
What you get is a disconnected grid. At layers 1, 3, 5, etc. you may have lines on one axis and at layers 2, 4, 6, etc. you may have a line along another axis perpendicular to the previous one.
As the name suggests, this pattern creates concentric rings that follow the shape of the outer walls.
Though it has very low strength at a low infill density, it is best for flexible parts that you want to bend. But if you increase the infill density, you would get a more rigid part.
However, at 100% infill density, the lines do not intersect and can distribute the load evenly, creating the strongest prints.
7. Cubic Subdivision
One could say that this is a “smarter” variant of the cubic pattern.
This pattern uses an algorithmically complex pattern that minimizes material use while maximizing printing speed without compromising overall strength.
This pattern involves cubes of different sizes. The largest cubes would be in the center whereas smaller ones will occupy the outer areas of your build. If you are looking for strength, weight reduction, and printing time, then it is difficult to beat this pattern.
This pattern consists of 3D cubes standing in a corner.
This unique orientation prevents overhangs (extrusions with no support). What you get in the end is a fairly high strength regardless of the direction of the force.
Moreover, this pattern also prevents the formation of long pockets of hot hair, which lowers the chance of pillowing at the top layer.
This pattern is suitable for parts that require strength along all axes. The cubic/honeycomb pattern, although it is a solid all-purpose option, it does have a relatively weak tensile strength.
9. Quarter Cubic
This pattern involves tetrahedrons and truncated tetrahedrons.
Similar to the octet infill pattern, this one establishes an internal frame to distribute the load equally. It is best for very thin functional parts that require a lot of strength.
However, the surface quality might not be perfect because of the long bridging distance.
This pattern involves tetrahedrons, or triangular pyramids, as well as cubes. So, what you get is a very strong internal frame where the edges of these shape meet.
This is a good infill pattern to use if you make thin mechanical parts.
Despite its high strength, keep in mind that the Octet infill pattern can create poor top surface quality.
This is thanks to the long bridging distance, which is the distance between two supported positions that your printer has to bridge across without support.
Similar to the line pattern. The key difference is that the nozzle goes back on itself when it reaches an outer wall instead of starting a new line. It is faster but also lacks strength, making it suitable only for decorative projects.
One reason to opt for the zig-zag pattern instead of a line pattern comes down to the nozzle movement. With the zig-zag pattern, it does not have to retract the filament and traverse.
This lowers the chance of the filament oozing, especially for low-viscosity filaments such as PETG. However, the zig-zag pattern does use a bit more material than the line pattern.
The cross pattern involves a pattern with bends to avoid creating any long straight horizontal lines.
What you get is a high level of flexibility across all horizontal directions. The cross pattern also does not require retraction, meaning that there is no oozing of materials.
However, one downside to this pattern comes down to its flexibility. Yes, the pattern is suitable for flexible parts due to its low geometrical strength, but only horizontally. It is pretty rigid along the Z-axis.
13. Cross 3D
The vertical strength in the cross pattern is no longer present when you take it up another dimension to 3D. In the end, you still have a relatively weak overall strength in all directions.
But that is okay because you should only use it for flexible parts. In terms of flexibility, the cross 3D pattern is better than the concentric or cross patterns.
Similar to the cross pattern, there is no retraction, meaning no oozing.
This one is the newest and probably the most efficient infill on the list. Cura introduced Lightening infill in 2022 available on from version 4.12.
The printed model is filled as “internal support” and creates an infill structure inside of the model in areas that are more challenging for your printer to print.
On the other hand, it reduces the amount of infill in areas which does not require being strong, or even can be printed with no infill.
The benefits are obvious: less material, lower printing time.
Lightening requires a bit of experience and knowledge, but is definitely worth exploring. You can read more about this new infill approach at Ultimaker blog.
Factors that Affect Infill Pattern Strength
Of course, the pattern is only one piece of the puzzle.
There are a few other things to consider that can affect the overall strength of your 3D prints.
Infill density is the ratio of plastic to space.
If your project has close to 0% density, that means it is mostly hollow, whereas anything close to 100% means that it is mostly solid.
Now, I know what you are thinking. Yes, 100% density will provide the best strength, but it is not practical for a few reasons.
For one, it is going to take your printer much longer to fill in the void with filament.
It will also make your build much heavier, and you will burn through much more filament.
Even worse still, there is a point of diminishing return in terms of overall strength.
Most builds only require 20-50% infill density because you would not get much more strength from your build beyond that point.
So, it is not practical to go 100% density in many cases.
Type of Force
Your 3D parts will have to withstand compressive or tensile force.
A compressive force is a crushing force, whereas a tensile force pulls the part along an axis.
Understanding the kind of load your 3D parts will have to withstand is critical in picking the best infill pattern.
3D parts perform better under compression force because of the plastic material and the layer-by-layer process of 3D printing.
Direction of Force
The overall strength of the infill patterns depends on the direction of the force.
For instance, the cubic infill pattern can handle compressive force along the Z axis well, but can fall apart if the horizontal force does not run parallel to the infill lines.
Understanding what kind of force and how it acts on your 3D print can help you figure out how to orient the infill pattern for maximum strength.
Here is a quick tip from yours truly: orient the layers parallel to the direction of the force.
You get the best strength under tensile and compressive loading. You can go a bit further on the parts before they start to fail.
The filament you use is also going to be critical for your project as the material you use is going to determine the overall strength of your infill.
ABS, PETG, and nylon can all provide great strength to your projects. PLA+ filaments with extra additives can also improve the PLA’s mechanical characteristics.
Overall, fibrous filaments will impart greater strength to your infill.
The quality of the filament also matters. A high-quality filament is a high-performing filament with higher tolerances, no impurities, and offers predictable results for your 3D projects.
While the deals from shady vendors seem tempting, I urge you to only purchase fresh and dry filaments from reputable vendors for the best results.
Not to mention, lower-quality filaments can also cause warping, voids, and other defects that compromise the structural integrity of your builds.
Flow Width and Rate
You can change the material’s width or flow rate during the printing process, or after it in the slicer settings.
By increasing the extrusion, you increase the surface area of the infill pattern, therefore improving the overall strength.
What you get is a project with a better capacity thanks to the optimization of load distribution over a larger area.
Keep in mind that you should use this sparingly because over-extruding can cause the shells to bulge. It can also ruin the appearance of your build and lower the precision of your 3D printer.
Number of Shells and Thickness
Another important factor comes down to understanding how your 3D parts bend.
The cubic subdivision puts smaller cubes toward the outer edge because that is where failure starts to form when under stress. Take a pencil and snap it in half.
You will notice that the outside area falls apart first.
So, you want to reinforce the outer perimeter of your build if you want to improve its strength. In this case, that would be the “shell”, wall, or perimeter (these 3 terms are synonymous).
How you approach this is up to you. Increasing the thickness of your wall has a similar effect to having multiple thinner walls.
And there you have it. These are my top picks for the strongest infill patterns in Cura. Of course, different patterns excel in handling different kinds of loads. Ultimately, it is up to you to understand each pattern’s strength and apply it to your projects.
Not to mention, you also need to consider other factors such as orientation, filament material, quality, etc.
For your convenience, consider the following:
- For decorative prints: lines and zig-zag
- For general prints: grid, triangles, tri-hexagon
- For functional prints: cubic, octet, cubic subdivision, quarter cubic, gyroid
- For flexible prints: cross, cross 3D, concentric and lightening
Hope you have found the answers to your questions. If you are interested to learn more about Cura and the functions it offers, check my other articles like how to use “pause at height“.