Wall thickness: how many millimetres you need in 3D printing

Why nozzle diameter matters

Our printers have a 0.4 mm nozzle, so one line of plastic is roughly 0.4 mm wide. A wall is made of a whole number of these lines. One line gives a wall of about 0.4 mm, two about 0.8 mm, three about 1.2 mm and so on.

If you design a 0.5 mm wall, the slicer rounds it, or it does not print at all. Thicknesses close to multiples of 0.4 mm work best.

Which thicknesses to use

• Under 0.8 mm. The wall may drop out or be fragile. See also smallest feature.
• 0.8 to 1.2 mm. Decorative parts and covers that do not carry anything.
• 1.2 to 2 mm. Ordinary boxes, holders and functional parts.
• 2 mm and more. Parts that flex, get screwed down or carry a load.

Walls, infill and strength

In 3D printing the load is not carried by the infill but mainly by the walls around the perimeter. See also walls in the slicer and infill. A thicker wall gives a stronger part faster than simply raising the infill.

In the calculator you choose light (10%), standard (15%) and strong (40%) infill. The wall thickness, however, comes from your model, and if a wall is too thin, infill will not make up for it.

Thickness and price

Thicker walls mean more grams and a longer print time, so a higher price per piece. Material costs 8 € per kilogram for PLA and 9 € for PETG, but most of the price is print time. More in the entry on hollow models.