HOW TO CHOOSE A LAYER HEIGHT

Layer height is the thickness of each printed layer. Smaller layers (0.08-0.12 mm) produce smoother surfaces and finer detail at the cost of much longer print time. Larger layers (0.28-0.32 mm) finish prints fast but show visible stair-stepping on curved surfaces and have weaker interlayer bonds. The rule that actually matters: layer height should be between 25% and 75% of your nozzle diameter. For a standard 0.4 mm nozzle, that's 0.1-0.3 mm. Outside that range, you either get extrusion problems (too thin) or weak layer bonds (too thick).

Use small layers (0.08-0.12 mm) for: miniatures, figurines, jewellery, models with fine surface detail. Trade-off: print takes 2-3x longer. Use standard (0.16-0.20 mm) for: general-purpose prints, functional parts, prototypes. Best balance of quality and speed. Use draft (0.24-0.32 mm) for: quick prototypes, structural parts where surface finish doesn't matter, large utility parts. Trade-off: visible layer lines and reduced strength. Don't use layer heights outside 25-75% of nozzle diameter. 0.05 mm on a 0.4 nozzle is too thin (extrusion is sketchy). 0.35 mm on a 0.4 nozzle is too thick (poor layer bonds).

1. Identify the use case. - Display piece / miniature: smaller is better. - Functional part: standard, prioritise strength over visuals. - Prototype / fast iteration: thicker layers. 2. Apply the nozzle-ratio rule. - Calculate min: nozzle diameter x 0.25. - Calculate max: nozzle diameter x 0.75. - For 0.4 mm nozzle: 0.10-0.30 mm range. - For 0.6 mm nozzle: 0.15-0.45 mm range. - For 0.2 mm nozzle: 0.05-0.15 mm range. 3. Common starting points by use case (0.4 mm nozzle): - Miniatures / figurines: 0.08 or 0.12 mm. - General prints / display: 0.16 or 0.20 mm. - Functional / mechanical: 0.20 or 0.24 mm. - Drafts / utility: 0.28 or 0.32 mm. 4. Match height to first layer too. - First layer should equal layer height or be slightly thicker (0.20 mm first layer for 0.16 mm subsequent layers). - Never first layer below 0.20 mm - too thin to bond reliably. 5. Special: variable layer height for mixed details. - Some slicers (PrusaSlicer, OrcaSlicer, Bambu Studio) support variable layer height - thicker layers in flat regions, thinner in curved regions. See how-to-use-variable-layer-height. 6. Slice and check print time. - Halving layer height roughly doubles print time. - Compare time estimates and decide if the visual gain is worth the time.

Layer height larger than 75% of nozzle. 0.32 mm on a 0.4 mm nozzle = poor interlayer bonding. Layer separation under load. Layer height smaller than 25% of nozzle. 0.05 mm on a 0.4 mm nozzle = extrusion too thin to flow consistently. Gaps and inconsistencies. Tiny layers on functional parts. A part for hot-glue gun mounting doesn't benefit from 0.08 mm layers - waste of time. Use 0.20 mm. Forgetting first-layer height. First layer at 0.10 mm doesn't bond well even though subsequent layers are fine. Keep first at 0.20 mm or thicker. Same layer height across all prints. Match to the use case - one default isn't optimal for everything.

For mixed detail in a single print, see how-to-use-variable-layer-height. For infill choice paired with layer height for strength, see how-to-choose-infill. Layer separation issues might trace to layer height too thick - see layer-separation.