The single biggest lever on bed adhesion in OrcaSlicer is the first layer height, and it is set independently of the rest of the print under Quality > Layer height > Initial layer height (the variable is initial_layer_print_height). The default is 0.20 mm regardless of the layer height you print the rest of the model at. A thicker first layer squashes more plastic into the build surface, bridges small levelling errors and gives the part a wider footing to hold on with — but go too thick and you invite elephant foot, go too thin and it will not stick at all. Everything else in this guide tunes around that one decision.
Below are the OrcaSlicer first layer settings for adhesion that actually matter, the numbers to start from, and the mechanisms behind each one so you can adapt them to your plate, nozzle and material rather than copying a profile blind.
First layer height: 50–65% of nozzle diameter
OrcaSlicer’s own wiki recommends 0.25 mm for a 0.4 mm nozzle — that is 62.5% of nozzle diameter — and caps the sensible maximum at 65%. Another rule of thumb in the docs puts the optimal point at 50% of nozzle width (0.20 mm on a 0.4 mm nozzle), with 65% as the ceiling before adhesion starts to suffer.
Sources genuinely disagree on the exact ideal here: 0.20, 0.24, 0.25 and 0.28 mm all appear in reputable guidance. That is not sloppiness — the right value depends on how flat your bed is and how aggressive your Z-offset is. On a textured PEI sheet with a slightly uneven plate, 0.24–0.28 mm fills the texture and hides minor low spots. On a glass-flat surface with a well-dialled offset, 0.20 mm prints cleaner. The practical guidance:
- Textured PEI / uneven bed: 0.24–0.28 mm (60–70% of a 0.4 mm nozzle).
- Smooth PEI / well-levelled bed: 0.20–0.24 mm.
- Avoid below 0.16 mm for the first layer unless your bed is exceptionally level — there is no margin for error.
A thicker first layer only works if your Z-offset is calibrated to match. If the first layer is too thin it will not bond; too thick and the extra plastic spreads sideways at the base as elephant foot. The two settings are joined at the hip.
First layer line width: go wider for the squish
Line width is a separate, underrated adhesion lever. The variable initial_layer_line_width (Advanced mode, accepts a float in mm or a percentage) controls how wide each first-layer extrusion is — and it also overrides the brim’s and skirt’s line width, so it sets the tone for the whole base.
The general line-width rule is to start at 100% of nozzle diameter. Going below that hurts adhesion; going above 150% causes over-extrusion, blobs and poor surface finish. For the first layer specifically, a slightly wider line gives you that “squish” that makes prints stick:
| Setting | Value (0.4 mm nozzle) | Note |
|---|---|---|
| Standard line width | 0.42 mm | Baseline for the model |
| First layer line width | 0.42–0.45 mm | Wider squish, better bed contact |
| Aggressive first layer | 0.45–0.50 mm | 125% of nozzle — near the over-extrusion zone, bed-dependent |
0.42–0.45 mm is the safe, widely used starting range. 0.50 mm on a 0.4 mm nozzle is 125% of diameter — it will fill the surface aggressively but sits close to over-extrusion, so only push there if you are chasing stubborn adhesion and you are watching the first layer go down.
First layer speed: slow it right down
Printing the first layer slower is one of the most reliable adhesion wins there is. Slower extrusion gives the molten plastic time to bond to the plate, reduces edge curling and lets the machine compensate for minor levelling inconsistencies. OrcaSlicer splits this into two settings:
initial_layer_speed— walls, and sparse infill when bottom layers is set to 0.initial_layer_infill_speed— solid infill regions of the first layer.
Recommended starting values:
| Printer type | First layer speed | First layer infill |
|---|---|---|
| Budget / older printers | 20–30 mm/s | 35–50 mm/s |
| High-speed printers | 40–50 mm/s | 35–50 mm/s |
| Safe universal default | 20 mm/s | 35 mm/s |
Community profiles sit around 15–45 mm/s for first-layer walls and 35–50 mm/s for first-layer infill, with initial-layer travel at 50% of normal. If a print keeps lifting at a corner, dropping first-layer speed to 20 mm/s is almost always more effective than cranking the temperature.
First layer temperature: a little hotter helps
OrcaSlicer carries separate first-layer temperatures for both nozzle (first_layer_temperature) and bed (first_layer_bed_temperature), and most filament profiles handle this automatically. Running the first-layer nozzle 5–10 °C hotter than the rest of the print lets the plastic flow into the texture of the plate and form a stronger mechanical bond.
The caution — straight from OrcaSlicer’s wiki — is that a higher first-layer temperature also encourages elephant foot. If you raise it, keep an eye on the base of the part and be ready to add elephant-foot compensation rather than drop the temperature back.
Bed temperature does the heavy lifting on adhesion. These are starting points, not absolutes; the ranges differ between sources, and material surface matters:
| Material | Nozzle (first layer) | Bed (first layer) | Enclosure |
|---|---|---|---|
| PLA | 180–220 °C | 50–60 °C | No |
| PETG | ~230–250 °C | 70–80 °C on PEI* | No |
| ABS / ASA | 230–250 °C | 90–110 °C | Yes |
*PETG bed temperature is genuinely contested: Bambu’s own PETG docs cite 45–70 °C on both textured and smooth PEI, while OrcaSlicer’s Generic PETG profile defaults to a 70 °C bed. In practice 70–80 °C on PEI is the community sweet spot. PETG also bonds too well to bare PEI — use a glue stick or textured sheet as a release layer or you will tear chunks out of the plate.
Cooling: keep the fan off early
Part-cooling fans fight adhesion by chilling the plastic before it bonds. OrcaSlicer gives you two controls:
close_fan_the_first_x_layers(“No cooling for the first”, Simple mode) — disables part-cooling fans for a set number of opening layers.initial_layer_fan_speed(“First layer fan speed”, Advanced; in nightly builds and releases after 2.4.2) — sets an exact first-layer fan percentage that overrides everything else.
Material-specific fan behaviour, which directly affects both adhesion and layer bonding:
- PLA: 100% after layer 2 — fine to cool early because PLA bonds to the plate readily.
- PETG: 30–50%, off for the first 4–6 layers. Too much fan ruins layer adhesion.
- ABS / ASA: 0–10%, off for the first several layers, enclosure required — fan causes warping and cracking.
- TPU: 0–30%.
Brim: the real adhesion helper
When settings alone will not hold a part down, a brim is the answer — extra first-layer loops printed around the model that massively increase contact area. The brim_type options are auto_brim, brim_ears (mouse ears), painted, outer_only, inner_only, outer_and_inner and no_brim. The default brim_width is 5 mm.
Useful specifics from OrcaSlicer’s auto-brim logic: the computed width is capped at 20 mm and at 1.5× the thermal length, and it scales adhesion by material coefficient — default 1, PETG/PCTG 2, TPU 0.5. That is why PETG and TPU get noticeably different auto brims from PLA.
| Situation | Brim? | Recommended width |
|---|---|---|
| Small base area | Yes | 5–10 mm |
| Sharp corners (ABS) | Yes | 8–15 mm or brim ears |
| Tall thin models | Yes | 10–15 mm |
| PLA on textured PEI | Often no | 3–5 mm or none |
Two settings make brims far more usable. The brim-object gap (set 0.1–0.15 mm) leaves a tiny separation so the brim peels off cleanly instead of fusing to the part. And combine_brims merges touching brims into longer continuous loops — a real help for small or closely spaced objects. For sharp-cornered rectangular ABS parts, brim ears painted onto the corners localise the adhesion exactly where lifting happens and leave almost nothing to clean up.
Outer-only brims are easier to remove; outer-and-inner gives the most adhesion but is harder to clean and can obscure fine detail. Start with outer-only and only add inner if a part keeps lifting from the middle.
Skirt: priming, not adhesion
A skirt is one or more perimeters printed around — but not touching — the model on the first layers. It primes the hotend, stabilises extrusion before the real print starts, and can double as a draft shield when built tall. skirt_loops defaults to around 2; more loops prime better and buffer the nozzle, at the cost of filament and time (0 disables it). skirt_distance sets how far the skirt sits from the brim or object.
Do not confuse the two: a skirt is a priming and diagnostic aid, not an adhesion feature. It is excellent for verifying adhesion, though — watch the skirt go down and you will see a dragging nozzle (too low), gappy lines (too high) or clean fat lines (just right) before the model commits.
A sensible starting recipe
For PLA on textured PEI, dialled in and reliable:
- First layer height: 0.24 mm
- First layer line width: 0.45 mm
- First layer speed: 20 mm/s walls, 35 mm/s infill
- Nozzle: +5 °C over print temp; bed 55–60 °C
- Fan: off for layer 1
- Brim: only if the base is small — then 5 mm outer with a 0.1 mm gap
If you want these verified before you commit filament, the G-code pre-flight checklist flags first-layer values that will cause trouble, and if a print has already failed, the diagnose-from-a-photo tool reads the defect and recommends the exact slicer change. For the deeper dive on each value, see our guide to OrcaSlicer first layer adhesion settings, and if you are on a Bambu machine, the P1S-specific settings. Over-extruding a wide first layer can also point to a calibration issue — our flow rate calibration method covers that.
FAQ
What is the best first layer height for adhesion in OrcaSlicer?
Between 50% and 65% of nozzle diameter — roughly 0.20–0.28 mm on a 0.4 mm nozzle. OrcaSlicer’s wiki recommends 0.25 mm. Use 0.24–0.28 mm on textured or slightly uneven beds and 0.20–0.24 mm on flat, well-levelled surfaces. Avoid going below 0.16 mm.
Should the first layer be hotter in OrcaSlicer?
Yes — most profiles set the first-layer nozzle 5–10 °C higher so the plastic flows into the plate texture and bonds. Watch for elephant foot; if it appears, add elephant-foot compensation rather than dropping the temperature.
Do I need a brim or a skirt for adhesion?
A brim, not a skirt. A brim adds first-layer contact area and directly fights lifting; 5–10 mm for small bases, 8–15 mm or brim ears for sharp ABS corners. A skirt only primes the nozzle and helps you check the first layer — it does nothing for adhesion.
Why does my PETG stick too well and damage the plate?
PETG bonds aggressively to bare PEI. Use a glue stick as a release layer or print on a textured sheet, keep the bed around 70–80 °C, and keep the part fan off for the first 4–6 layers so the base cures gently rather than being ripped out on removal.
Related: First Layer Settings in OrcaSlicer: The Exact Values That Make Prints Stick