Choosing the right layer height for FDM production
How layer height from 0.10 to 0.30 mm affects strength, surface finish, Z accuracy, stair-stepping, hole quality, print time and cost.
Layer height is unusual among FDM parameters because it is not something you design into the geometry, it is a machine setting chosen per job. We run 0.10 to 0.30 mm depending on the part. That range sounds small, but it changes strength, surface finish, dimensional accuracy in Z, the visibility of stair-stepping, the roundness of small holes and the price of the part, all at once and often in opposite directions.
Effect on strength
Thinner layers generally bond slightly better to each other, because each new layer re-melts a thinner cross-section of the one below it, improving fusion. The effect on overall part strength is real but secondary to wall count, orientation and material choice. A part loaded mainly in the XY plane will not gain much from a finer layer height, while a part loaded across layer lines, in the Z direction, can see a modest improvement, though it is rarely enough on its own to fix a genuinely weak design.
Effect on surface finish and Z accuracy
Surface finish on vertical walls is dominated by extrusion width and cooling, but on sloped and curved surfaces layer height is the main driver of visible texture. Z accuracy, the dimension built up along the stacking direction, is generally tighter at finer layer heights because each layer contributes a smaller, more consistent increment and rounding error accumulates less over the height of the part. For features with a tight Z tolerance, choosing 0.15 mm or 0.10 mm over 0.30 mm can be the difference between passing and failing a fit check.
Stair-stepping on sloped and curved surfaces
Stair-stepping is the visible terracing that appears wherever a surface is not vertical or horizontal, because each layer is a flat slab and a sloped surface can only be approximated by the edges of stacked slabs. The size of each visible step is roughly the layer height divided by the sine of the slope angle from vertical, so a shallow slope shows much larger steps than a steep one at the same layer height. A 10 degree slope at 0.30 mm layer height produces steps around five times larger than the same slope at 0.10 mm, which is why cosmetic curved surfaces are usually printed at the finer end of the range or reoriented to reduce the shallow angles.
Small hole quality
Small holes printed with the axis vertical are built up as a series of stacked circular layers, and coarser layer heights make each individual layer's slight polygonal deviation more visible in the final bore, along with more pronounced ridges on the inside wall. For holes under about 5 mm diameter that need good roundness for a pin or dowel fit, a finer layer height, 0.10 to 0.15 mm, noticeably improves out-of-the-box roundness compared to 0.30 mm, though for critical fits we still recommend drilling or reaming to final size regardless of layer height.
Print time and price
Print time scales roughly inversely with layer height for a given part height, because a taller stack of thinner layers means more total layers to print, each with its own travel moves and settling time. Doubling the layer height from 0.15 mm to 0.30 mm roughly halves the number of layers and typically cuts print time by 35 to 45 percent, since some time-dependent steps like travel moves do not scale perfectly linearly. For production volumes, this makes layer height one of the most direct levers on unit cost.
| Layer height | Typical use case | Relative print time |
|---|---|---|
| 0.10 mm | High detail, tight Z tolerance, cosmetic curved surfaces | ~180 percent |
| 0.15 mm | Visual prototypes, small holes and pins, fine features | ~130 percent |
| 0.20 mm | Default for most functional and production parts | 100 percent (baseline) |
| 0.25 mm | Larger structural parts, moderate detail requirements | ~80 percent |
| 0.30 mm | Large, mostly cosmetic-tolerant structural parts, high volume | ~65 percent |
Frequently asked questions
- What layer height do you use by default?
- 0.20 mm for most functional and production parts, since it balances surface quality, accuracy and print time well. We move to finer settings for parts with cosmetic curved surfaces or tight Z tolerances, and coarser settings for large structural parts in higher volumes.
- Does a finer layer height make the part stronger overall?
- It helps modestly, mainly for loads that act across layer lines, but wall thickness, perimeter count and orientation have a much larger effect. Do not rely on layer height alone to fix a design that is weak for structural reasons.
- Should cosmetic parts always use the finest layer height?
- Only on the surfaces where it matters. We often print a part at a moderate layer height and orient the highest visibility surface to minimise stair-stepping instead of defaulting to the finest setting for the whole part, which keeps cost under control.
- Can layer height fix a hole that needs to be perfectly round?
- It improves roundness noticeably but does not eliminate the underlying limitation of building a circle from stacked layers. For a genuinely critical fit, we recommend printing slightly undersized and drilling or reaming to final diameter.
- How much does switching from 0.30 mm to 0.15 mm actually add to cost?
- As a rough guide, expect print time and therefore machine cost to roughly double, since the part needs about twice as many layers. Material use stays essentially the same, so the increase shows up mainly in machine time rather than filament.
Have your part reviewed before production
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