Glossary · Setting

3D printing

Infill

The fill inside a print. Printed parts are usually not solid inside but filled with a lattice pattern.

Explained in more detail

Given as a percentage of the interior volume. Decorative: 5 to 15%, everyday parts: 15 to 25%, load-bearing functional parts: 30 to 50%. Patterns such as gyroid, grid, cubic or lightning affect strength, print time and material use. For strength, extra walls (perimeters) and top layers are often more effective than more infill.

Where does the term come from?

Infill comes from "to fill in". It means the filling between the outer walls.

In practice

• Rule of thumb for functional parts: 3 to 4 walls, 4 to 5 top and bottom layers and 20 to 30% infill.
• If the pattern shows through on the top surface or holes appear, it is usually the top layers that are missing, not infill.
• With TPU, the infill controls hardness: little infill makes a part flexible, a lot of infill makes it firm.
• With modifiers you reinforce individual areas selectively, for example around screw holes, instead of filling the whole part more densely.

Not to be confused

The percentage applies only to the interior: 20% infill does not mean the part weighs 20% of a solid part, because walls and top layers are always printed solid.

Frequently asked questions

Which infill pattern is the strongest?

Gyroid and cubic are similarly strong in all directions and good all-rounders for functional parts. Honeycomb is very strong but prints slowly. Lightning supports only the top surface and suits decoration.

Does more infill make a part stronger?

Up to about 50% yes, above that hardly. A part with 4 walls and 20% infill is often stronger than one with 2 walls and 50% infill, and it prints faster.