Jun 22, 2018

Infill (3D Printing) – What It Means and How to Use It

When it comes to 3D printing, infill is a very important factor to a print's strength, structure, and weight. We look at the various forms and shapes of infill in order to find out why they're necessary and what makes them different.

The Purpose of 3D Printing Infill

If you try to look at the definition of 3D printing infill on Wikipedia or TechTerms, you’ll find that there isn’t one. Not to worry — it’s very easy to understand. Infill is simply a repetitive structure used to take up space inside an otherwise empty 3D print. For the majority of prints, infill is hidden from view, but occasionally, special infill patterns are more than worthy of showing off.

Of course, infill has other purposes. In addition to filling the empty space in a print, infill can also change it’s weight, depending on the material used. Furthermore, infill allows printers to print flat horizontal edges over empty space reliably and efficiently. Without it, prints wouldn’t have much structure or stability, making them incredibly fragile.

Often overlooked, infill is perhaps one of the most important factors in 3D printing, and a rather variable one at that. With numerous patterns, densities, styles, and orientations, optimizing infill can be a daunting task. However, with the right knowledge, customizing can be fun!

Styles and Uses of 3D Printing Infill

Infill comes in many shapes, sizes, and patterns. Each style has its own strengths and weaknesses, and each its own use. Though infill can take countless forms, there are several fairly standard patterns.

Since infill takes up the space inside a print, it makes sense that infill designed for structure works better than infill designed for aesthetics. In this case, patterns incorporating grids, lines, honeycombs as well as rectilinear or concentric patterns work best.

As long as the density is set correctly, these patterns give enough volume for printing between the gaps. This allows the printer to print over empty space more accurately, and with less error.

3D printing infill like the “octi” and “archi” designs in the image are more suitable for circular or rounded designs. Meanwhile the “Hilbert” and “3D honey” designs are better for block-oriented prints.

Densitiy of 3D Printing Infill

Once you’ve decided on a style, the next step is to set the density of your 3D printing infill, measured in percent. 0% is generally equivalent to no infill and 100% is equivalent to a solid print. Of course, there are many levels in between, and adjusting this value is incredibly useful in accommodating a variety of functions.

One very obvious use is to vary the mass of the print. A higher infill density makes for a heavier, more solid print. In contrast, a lower infill density would provide a simpler, more lightweight result. Infill density can also effect a print’s strength, bouyancy, and material used.

Common infill densities are between 20% and 25%. This offers a nice balance between durability and material consumption. If structure isn’t a concern but cost is, the best infill range is between 10% and 15%.

None of these ranges give much support, so don’t use them if your object needs to be strong, or needs structure during printing. Finally, if structure is a concern, and filament usage isn’t, the best range is somewhere between 30% and 50%.

Lastly, if you’re going for strength, as with a functional part, feel free to go right up to 100%.

With so much customization available, and with all of the differences between 3D printers, infill should be carefully considered to fit your needs. Without it, 3D printing as we know it today simply could not exist.

License: The text of "Infill (3D Printing) – What It Means and How to Use It" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.

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