“Filling in” – What do we need to know when 3D print
Do you know what distinguishes 3D printing from most other manufacturing techniques? That while printing with a 3D printer, you have control over the simultaneous construction of both the outer walls of an object and what fills it. In this case, the walls form the outermost layers of the part you are building. The material between these walls is called filler.
In 3D printing, the filler plays a key role in the strength, structure and weight of the object you are creating. The interesting thing here is that you have the opportunity to define a number of parameters that control the type of this filling. The two most important are the filling density and the filling pattern. This is what we will be talking about in this article.
But first, let’s see why filling is so important for creating 3D objects.
3d printing vs traditional manufacturing
The “Filling in” is a different technique from other, more traditional manufacturing methods. To explain the difference, we will use injection molding and substrate production for examples.
Injection molding is done by inserting a material into a mold to form parts. The trick here is that it is virtually impossible to control internal structures. As a result, the parts are either too hard or hollow.
On the other hand, subtractive production, such as CNC milling, involves cutting material from a larger piece. Like injection molding, the filling cannot be adjusted as the interior is too hard.
This is what makes 3D printing so effective. As it involves selective extrusion of material, you do not have to face such difficulties.
Now that we understand why filling is so important in 3D printing, it’s time to look at the different types of densities and fill patterns.
Density
The filling density is the “completeness” of the inside of the object. In slicers, this is usually defined as a percentage between 0 and 100, with 0% making the object hollow and 100% completely solid. By logic, this has a big impact on the weight of the object: the fuller the inside – the heavier it is. In addition to weight, density also affects printing time, material consumption, and buoyancy.
Some slicers allow different filling densities within the same object. This is known as variable fill density, and specific settings in the slicer program allow you to set different density changes for each area of the model you are printing.
How to choose the correct density?
For most “standard” 3D printed models/objects that don’t need to be super strong, a fill density of 15% to 50% would do a great job. With this percentage of density, the printing time is not too long, saves material and provides good strength.
If you are printing more big or complicated objects, it would be good to set the density above 50%. This will increase the time for 3D printing, but as a result you will get a solid and heavier object.
But if you build smaller objects and don’t aim them be heavy or too hard, a density below 15% will work just as well. In addition, your 3D object will be printed much faster with much less material.
Keep in mind, however, that the lower the density is, the more flexible your objects will be.
Recommended density percentages:
- Standard objects: from 15% to 50%
- Functional objects: from 50% to 100%
- Smaller objects and models: from 0% to 15%
- Flexible objects: from 1% to 100%
Patterns
The fill pattern is the structure and shape of the material inside the 3D printed object. Ranging from simple lines to more complex geometric shapes, patterns can affect the strength, the weight, the printing time, and even the object flexibility.
Like the fill density, some patterns are better than others for certain features. Different filling patterns have different features, such as complexity, material efficiency and number of planes of bond strength (2D or 3D).
How to choose the correct pattern?
By examine the different types of patterns, you will be able to choose who would do the best job for you, according to the type and functionality of the elements you are 3d printing.
Lines: This template pattern contains lines printed in one direction (along the X or Y axis). This provides strength in just two dimensions, which is effective for fast prints. The lines do not use too much material and keep the object weight quite light.
Honeycomb: As the name suggests, this pattern creates the structure of a honeycomb, which makes an interesting visual effect. This type of filling is good for semi-fast prints that require moderate strength and do not require the consumption of too much material.
Grid: The grid resembles the appearance of lines, but instead of one-way lines on each subsequent layer, this pattern template contains two-dimensional lines on each layer, with twice the space between the rows. This provides two-dimensional strength, but is still somewhat strong. The mesh pattern consumes an average amount of material and takes an average time to complete.
Triangles: This pattern looks like overlapping triangular lines, with lines running in three directions in the XY-axes. This provides strength in only two dimensions, but is effective for prints that require more solid strength.
Tri-hexagon: The three-hexagon filling pattern contains a set of lines running in three directions in the XY-axes, creating hexagonal patterns with triangles in between. This pattern provides strength in two dimensions and is effective for strong prints.
Cubic: This pattern creates stacked cubes, but because they are tilted 45 degrees around both X and Y axes, they look more like triangles at any given time. The pattern provides excellent strength in three dimensions, but exhaust a little more material and time than the others.
Octet: The octet is similar to the cubic pattern, but instead of enlarging the inclined triangles, the pattern materializes as squares. This pattern is three-dimensional, which is extremely useful for parts that require serious durability.
Giroid: The Giroid pattern is probably the most attractive looking, but also the strangest filling pattern. It includes concave irregular curves that intersect. This achieves an optimal balance between strength, material and printing time.
Concentric: The concentric pattern is an internal structure composed of concentric lines that coincide with the outline of the object (its perimeters). This template pattern prints quickly, it is good for printing flexible objects and consumes significantly less material than most other patterns.
Recommended settings:
- Standard objects: Grid, Triangles
- Functional objects: Cubic, Gireoid, Octet
- Smaller figures and objects: Lines
- Flexible objects: Concentric pattern.
Other important settings for 3D printing:
In addition to density and fill pattern, there are two other key categories of filling settings: variable settings and artistic patterns. The interesting thing about both is that they allow you to be more creative with the fill settings.
Variable settings
Variable settings allow you to adjust the density of the filling as the object progresses in layers. For example, if you want the base of your object you’re to have 10% fill to layer 30 and then move up to 50% fill, the variable settings allow you to do that.
Artistic patterns
Artistic patterns help you turn ordinary templates into a real work of art. This would be extremely useful if you make jewelry or other decorative patterns.
