Choosing the right layer height: quality versus print time
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Layer height determines how thick each printed layer is. It is the setting with the greatest influence on print time and appearance. Thin layers look finer but take much longer. Thick layers are fast but show visible steps.
The rules of thumb
- Standard with a 0.4 mm nozzle: 0.2 mm. This is the best compromise for most prints.
- Upper limit: about 75 to 80 % of the nozzle diameter, so around 0.3 mm for 0.4 mm.
- Lower limit: about 25 % of the nozzle diameter, so around 0.1 mm for 0.4 mm. Going thinner brings hardly any visible gain with FDM.
- Halving the layer height roughly doubles the print time.
Which layer height for what?
| Layer height (0.4 mm nozzle) | Typical for | Print time |
|---|---|---|
| 0.08 to 0.12 mm | figures, fine details, round surfaces | very long |
| 0.16 mm | good appearance at a reasonable time | long |
| 0.20 mm | standard for almost everything | medium |
| 0.24 to 0.28 mm | functional parts, prototypes, large parts | short |
With larger nozzles, the values shift accordingly. A 0.6 mm nozzle prints well at 0.3 to 0.4 mm.
Where layer height becomes visible
On vertical walls, you can hardly see any difference between 0.12 and 0.2 mm. Layer height becomes clearly visible on sloping and round surfaces, for example on a dome or a face. There, thick layers produce visible stair steps.
Variable layer height
Many slicers can vary the layer height within a model: thin layers on sloping areas, thick layers on vertical ones. This saves a lot of time with almost the same appearance. The function is usually called “Variable layer height” or “Adaptive layer height” and can be calculated automatically or adjusted by hand.
And what about strength?
The layer boundaries are the weakest point of an FDM print. Layer height alone, however, hardly makes a part stronger or weaker. Much more important for strength are:
- the number of walls
- the right printing temperature for good layer adhesion
- the orientation of the part on the print bed, so that the forces do not act across the layers
The first layer
The first layer is often somewhat thicker, for example 0.2 to 0.3 mm. This compensates for small unevenness of the print bed and improves adhesion. The manufacturer profiles in the slicer usually already set this appropriately.