Introduction
Layer height is the single setting that most directly trades speed against surface finish. Drop it too low and a simple print takes all day; raise it too high and your part looks ribbed and rough. Understanding what layer height does, and how it interacts with your nozzle and material, is the fastest way to print the right part at the right time.
What Layer Height Actually Is
Layer height is the vertical thickness of each slice of plastic the printer lays down. A 0.2 mm layer height means every layer is 0.2 mm tall, so a 20 mm cube contains 100 layers. Smaller layers stack more slices to fill the same height, which is why fine prints are smoother but slower. The visible horizontal ridges on a print are simply the boundaries between layers.
The Three Common Settings
Most slicers center their profiles around three useful values. A fine 0.10–0.12 mm layer height produces near-smooth curves and crisp details, ideal for miniatures, lithophanes, and cosmetic parts. A standard 0.20 mm layer height is the everyday workhorse, balancing quality and speed for most functional and decorative prints. A draft 0.28–0.32 mm layer height trades surface finish for speed, perfect for prototypes, brackets, and parts that will be sanded or painted.
Match Layer Height to Your Nozzle
Layer height is constrained by your nozzle diameter. A good rule of thumb is to stay between 25% and 75% of the nozzle width. On a standard 0.4 mm nozzle, that means roughly 0.10 mm to 0.30 mm. Going below the lower bound weakens layer bonding, while going above the upper bound leaves gaps and poor adhesion. If you want dramatically finer detail, switch to a smaller nozzle rather than cranking the layer height down.
How Layer Height Affects Strength
Counterintuitively, larger layers often produce stronger parts. Thicker layers fuse more completely and leave fewer weak interfaces, while ultra-fine layers can create more bond lines that concentrate stress. For load-bearing or functional parts, a 0.20 mm layer with solid wall and infill settings usually outperforms a 0.10 mm cosmetic print. Choose fine layers for looks, standard layers for strength.
Time and Material Trade-offs
The cost of fine detail is steep and non-linear. Halving the layer height from 0.20 mm to 0.10 mm roughly doubles the number of layers and the print time, but only improves smoothness by a modest amount on most geometry. Before you drop the resolution, ask whether the part is cosmetic or functional, and whether post-processing such as sanding or vapor smoothing would achieve the same finish faster.
Adaptive Layers as a Middle Ground
Many modern slicers offer adaptive layer heights, which use fine layers on steep curves and thick layers on flat walls automatically. This gives you smooth detail where it matters and speed everywhere else, without manually splitting the model. It is the best of both worlds for parts that mix organic curves with large flat areas.
Conclusion
Layer height is not a setting to max out; it is a dial that balances surface quality, strength, and time. Use fine layers for cosmetic parts, standard layers for functional parts, and draft layers when speed matters most. Match it to your nozzle, and let adaptive layers do the thinking when geometry gets complicated.