Wall thickness for 3D printing: 0.8 mm minimum, 1.5 mm recommended

Wall thickness means two things. In CAD (computer-aided design) it is the distance between a wall’s two faces: model filament (FDM) walls at least 0.8 mm thick, and 1.5 mm where the part allows. In the slicer it is the wall count times the line width: on a 0.4 mm nozzle, 2 walls (the usual default) make 0.8 to 0.9 mm and 4 make 1.6 to 1.71 mm.

What does wall thickness mean in 3D printing?

Two settings share the name:

Meaning	Where it is set	Example
Model wall thickness	Your computer-aided design (CAD) program: the distance between a wall’s two faces	A 2 mm box wall
Slicer wall (shell) thickness	Wall loops in Bambu Studio and OrcaSlicer, Perimeters in PrusaSlicer, Wall Thickness or Wall Line Count in UltiMaker Cura	2 walls of 0.45 mm = 0.86 mm

The slicer prints its walls inside the model’s outline and fills the rest with infill. In Cura, Wall Thickness covers the side walls only; top and bottom thickness are separate settings.

What is a good wall thickness for 3D printing?

About 1.5 mm for FDM parts: Xometry’s design guide recommends 1.5 mm for supported and unsupported walls alike. On a 0.4 mm nozzle that means 4 walls, 1.6 mm in UltiMaker Cura and 1.67 mm in PrusaSlicer. The slicers’ default 2 walls (0.8 to 0.9 mm) only meet the 0.8 mm minimum.

Source	Process and wall	Minimum	Recommended
Protolabs	FDM, supported or unsupported	0.8 mm	not given
Hubs (Protolabs)	Any 3D printer	over 0.8 mm	not given
Xometry	FDM, supported	0.75 mm	1.5 mm
Xometry	FDM, unsupported	1 mm	1.5 mm
Hubs (Protolabs)	Enclosure walls	2 mm	not given
Formlabs	Resin, Form 4	0.2 mm	not given

A supported wall joins other walls on two or more sides; an unsupported one, such as a free-standing fin, joins fewer (Formlabs’ definitions). Hooks, brackets and toys get bent and dropped, so give them more walls before more infill.

What is the minimum wall thickness for 3D printing?

0.8 mm for FDM printing. Protolabs sets 0.8 mm for supported and unsupported walls. Xometry’s capability floor is 0.75 mm for a supported wall and 1 mm for an unsupported one. Resin goes thinner: Formlabs lists 0.2 mm on the Form 4.

The thinnest wall a slicer will print

Slicers print whole lines, counted from both faces of the wall. On a 0.4 mm nozzle:

Wall as drawn	What the slicer prints
2 lines or more: 0.83 mm Bambu Studio, 0.86 mm PrusaSlicer, 0.8 mm Cura	A full wall from each face
Between 0.34 mm and 2 lines, variable-width walls	One or two lines, their width varied to fill the wall
0.1 to 0.34 mm, variable-width walls	One line widened to 0.34 mm (85% of the nozzle)
Under 0.1 mm (25% of the nozzle), variable-width walls	Nothing
Under one 0.42 mm line, Bambu Studio’s Classic walls	No wall is generated, so the feature goes missing

The variable-width rows apply to Prusa’s PrusaSlicer profiles (Arachne generator) and to Cura (Minimum Wall Line Width, Minimum Feature Size). Bambu Studio’s own profiles use the Classic generator with Detect thin wall off. To print a thin feature there, set Wall generator to Arachne (Process → Quality) or turn on Detect thin wall (Process → Strength → Walls).

How thick are 2, 3 and 4 walls?

On a 0.4 mm nozzle, 2 walls are 0.8 to 0.9 mm, 3 are 1.2 to 1.31 mm and 4 are 1.6 to 1.71 mm. PrusaSlicer, Bambu Studio and OrcaSlicer overlap neighboring lines, so Prusa’s knowledge base puts two 0.45 mm perimeters at 0.86 mm rather than 0.90 mm.

Slic3r family:  wall = w + (walls − 1) × (w − 0.215 × h)
UltiMaker Cura: wall = walls × w

w is the line width and h the layer height. For 4 PrusaSlicer walls of 0.45 mm at 0.2 mm layers: 0.45 + 3 × (0.45 − 0.043) = 1.671 mm.

0.4 mm nozzle, 0.2 mm layers:

Walls	PrusaSlicer, 0.45 mm	Bambu Studio, 0.42 / 0.45 mm	OrcaSlicer 0.45 mm, Precise wall	UltiMaker Cura, 0.4 mm
1	0.45 mm	0.42 mm	0.45 mm	0.4 mm
2	0.857 mm	0.827 mm	0.9 mm	0.8 mm
3	1.264 mm	1.234 mm	1.307 mm	1.2 mm
4	1.671 mm	1.641 mm	1.714 mm	1.6 mm
5	2.078 mm	2.048 mm	2.121 mm	2.0 mm
6	2.485 mm	2.455 mm	2.528 mm	2.4 mm

OrcaSlicer’s Precise wall, on by default, removes the overlap between the outer wall and the first inner wall when walls print in the default inner/outer order. Bambu Studio ships with it disabled.

Other nozzles, Bambu Studio’s standard presets:

Nozzle	Line width and layer	Preset walls	2 walls	3 walls	4 walls
0.2 mm	0.22 mm at 0.10 mm	4	0.42 mm	0.62 mm	0.82 mm
0.4 mm	0.42 / 0.45 mm at 0.20 mm	2	0.83 mm	1.23 mm	1.64 mm
0.6 mm	0.62 mm at 0.30 mm	2	1.18 mm	1.73 mm	2.29 mm
0.8 mm	0.82 mm at 0.40 mm	2	1.55 mm	2.29 mm	3.02 mm

To model a thin wall, draw it at the thickness listed above for its total line count, both faces included. The line width calculator gives the exact figure for any nozzle, line width and layer height.

How many walls should a 3D print have?

At least two, and four where you want the recommended 1.5 mm wall. Two is the default in Bambu Studio, Prusa’s PrusaSlicer profiles and UltiMaker Cura. On a 0.4 mm nozzle they make 0.8 to 0.9 mm, which meets the 0.8 mm minimum; four make 1.6 to 1.71 mm. OrcaSlicer’s generic profiles use three.

Slicer	Setting	Where	Default
Bambu Studio	Wall loops	Process → Strength → Walls	2; 4 with a 0.2 mm nozzle
OrcaSlicer	Wall loops	Process → Strength → Walls	3 in generic profiles, 2 built in
PrusaSlicer	Perimeters	Print Settings → Layers and perimeters → Vertical shells	2 in Prusa’s profiles, 3 built in
UltiMaker Cura	Wall Line Count, or Wall Thickness in mm	Print settings → Walls	2, from 0.8 mm

How to increase wall thickness

1. Pick the count from the tables above: 1.5 mm on a 0.4 mm nozzle takes 4 walls.
2. Set Wall loops (Bambu Studio, OrcaSlicer), Perimeters (PrusaSlicer) or Wall Line Count (Cura) to 4. In Cura you can type Wall Thickness 1.6 mm instead.
3. Check the model: a wall drawn 1 mm thick has no room for 4 lines from each face, so thicken it in CAD.

Are more walls or more infill better for strength?

More walls. Prusa’s knowledge base says a model’s strength is mostly defined by the number of perimeters, not infill, and UltiMaker says two extra perimeters often add more strength than raising infill from 20% to 30%. Infill still helps against crushing: Prusa credits it with compression resistance.

In a 2019 test, CNC Kitchen broke PLA (polylactic acid) hooks printed standing on an Original Prusa i3 MK3S with no infill, so only the walls carried the load. The weakest of 23 hooks (116 N) had 2 perimeters from a 0.4 mm nozzle: 0.84 mm walls. All five variants with 1.68 mm walls, whether 4 perimeters from a 0.4 mm nozzle or 2 from a 0.8 mm one, broke between 347 and 380 N. Strength rose roughly in proportion to the plastic in the walls.

Two extra walls also use less plastic than 10 more points of infill, except on small parts. PLA cubes in the print weight calculator’s model (0.45 mm lines, 5 top and 3 bottom layers at 0.2 mm, 1.24 g/cm³):

Cube	2 walls, 20%	Add 2 walls	Raise infill to 30%
20 mm	3.9 g	+1.3 g	+0.7 g
40 mm	23.9 g	+5.5 g	+6.9 g
60 mm	71.8 g	+12.5 g	+24.5 g

Wall thickness for PLA, PETG and resin

PLA and PETG (polyethylene terephthalate glycol) take the same wall thickness. Protolabs gives one 0.8 mm minimum for PLA, PETG, ASA, ABS and TPU.

Resin walls can be far thinner: Formlabs recommends at least 0.2 mm for supported and unsupported walls on the Form 4 (Grey Resin V5 at 50 µm layers), and its Form 2 guide (Clear Resin at 100 µm) set 0.4 mm. Walls at or under 0.2 mm may warp, and unsupported ones may detach. Thin walls also soak up isopropyl alcohol in the wash, so Formlabs advises short immersion.

A hollowed resin model needs a thicker shell. PrusaSlicer’s resin hollowing defaults to a 3 mm wall and accepts 1 to 10 mm (Print Settings → Hollowing → Wall thickness). Formlabs’ PreForm leaves any region thinner than twice the set wall thickness solid.

Wall thickness for a 3D printed box or lamp shade

Hubs (Protolabs) recommends at least 2 mm for every enclosure wall, with ribs and gussets at 75 to 80% of it. Around a screw hole it asks for at least one hole diameter of wall (5 mm around an M5).

On a 0.4 mm nozzle in PrusaSlicer, 2 mm falls between 4 lines (1.67 mm) and 5 (2.08 mm). A wall modeled 2.49 mm thick with 3 perimeters fills exactly with 6 lines. For a drop-in lid, the tolerance calculator gives the clearance per side and the snap-fit box lid guide sizes the skirt.

Spiral vase mode prints a vase or lamp shade as one perimeter with no infill or top layers, so the wall is one line wide: 0.45 mm in PrusaSlicer, 0.42 mm in Bambu Studio and 0.4 mm in Cura. Prusa suggests widening External perimeters (Print Settings → Advanced → Extrusion width) for a stronger, watertight vase, for example from 0.45 to 0.6 mm.

Slicer	Spiral vase setting
Bambu Studio, OrcaSlicer	Process → Others → Special mode → Spiral vase
PrusaSlicer	Print Settings → Layers and perimeters → Vertical shells → Spiral vase
UltiMaker Cura	Special Modes → Spiralize Outer Contour