What fan speed percentage should you use for cooling in 3D printing? Short answer: 100% for PLA, 30–50% for PETG, and only 0–20% for ABS and ASA — but that's just the starting point, because good cooling isn't one universal percentage, it's a curve matched to the material, the geometry, and the stage of the print. If your prints are stringing or have smeared top layers, nine times out of ten the fan is the culprit, not the nozzle temperature.
In this guide you'll find a ready-made settings table for every popular material, an explanation of why cooling works the way it does, and a list of the mistakes that most often ruin prints for beginners and experienced printers alike. These settings apply to standard 0.4 mm nozzles and typical radial (blower) part-cooling fans mounted on the hotend — if your setup differs, treat these numbers as a starting point for your own calibration.
Starting settings — fan speed table for every material
| Parameter | Value | Comment |
|---|---|---|
| PLA (standard, Premium) | 90–100% from layer 2–3 | The stronger the airflow, the sharper the edges and smaller the overhangs' sag |
| PLA with additives (CF, Wood, Stone) | 80–100% | Mineral and wood fillers conduct heat slightly worse than pure PLA |
| PLA Silk / Rainbow | 70–90% | Too much cooling kills the characteristic gloss |
| PETG | 30–50% | Too much cooling = weak layers, too little = stringing |
| HT-PETG | 30–50% | Similar to PETG, slightly higher heat tolerance |
| ABS | 0–20% | Turn it off on the body, keep it only for fine details |
| ASA | 0–20% | Like ABS — the priority is avoiding stress, not layer stiffness |
| TPU 95A (soft) | 20–40% | Too strong an airflow on a Bowden setup encourages jams |
| TPU 98A (harder) | 30–50% | Higher Shore hardness tolerates more cooling than 95A |
| PA (nylon) | 0–30% | Nylon is hygroscopic — cooling won't replace drying |
| First layer (any material) | 0% | Turn the fan on only from layer 2–3 onward |
| Bridges and fine details | +20–30 pts locally | Even ABS and ASA get a brief local airflow boost on thin elements |
You'll find full nozzle and bed temperature settings for each of these materials in our print temperature table — cooling and temperature are two parameters that need to be tuned together, not separately.
Why cooling matters
The part-cooling fan doesn't cool the filament — it solidifies it at the right moment. Freshly extruded material leaves the nozzle in a semi-liquid state and needs to firm up fast enough to hold the shape of the next layer, but slowly enough to still bond with the layer beneath it. That's exactly the same principle we cover in our guide on first layer settings — there it's about adhesion to the bed, here it's about adhesion between layers, but the thermal mechanism is identical.
Too little cooling and the printer can't keep up solidifying thin walls, bridges, or sharp corners — the result is smeared details, sagging bridges, and stringing, because the molten material stays liquid too long between head movements. Too much cooling and the layers cool before they can properly bond — the print becomes brittle, cracks along the layer lines, and in materials with high shrinkage (ABS, ASA, nylon) uneven cooling creates stresses that peel corners off the bed.
That's why there's no single "right" fan percentage — there's a correct percentage for a specific material, a specific geometry, and a specific stage of the print. The table above is a starting point, but the final calibration should always be done on a test model with bridges and overhangs, not on your target project.
How the cooling fan works on a 3D printer
Most FDM printers have two independent fans on the hotend, even though people often think of them as one device. The first is the part-cooling fan — a small radial "blower" aimed directly at the freshly printed layer, controlled by the slicer from 0 to 100% for every layer individually. The second is the hotend fan (heatbreak fan or side fan), which cools the heatsink above the melt zone and runs almost constantly, regardless of the material profile settings.
Part-cooling fan vs. hotend fan (side fan)
This distinction matters in practice: when this guide says "set the fan to 30% for PETG," it refers only to the part-cooling fan in the slicer profile (Cooling → Fan Speed). The hotend fan is never turned off, regardless of material — its job is to protect the heatsink from heat creep, meaning heat crawling upward into the hotend, which leads to a clogged nozzle right in the middle of a print. If your printer lets you control both fans separately in firmware, leave the side fan at 100% at all times.
Cooling PLA and PLA-based filaments
PLA is the one popular material where "more cooling" almost always means "better." Its low melting temperature and minimal shrinkage mean PLA tolerates a full 100% fan speed without losing inter-layer strength — which is exactly why it's the material most often recommended to beginners: it forgives mistakes that would end in a cracked print with ABS.
Standard and Premium PLA
For regular PLA and Porima PLA, set the fan to 0% on the first layer, then raise it to 90–100% from the second or third layer and leave it there until the end of the print. The only exception is very large, flat surfaces — there, a slight reduction to 70–80% limits microscopic stresses that can lift the corners of longer models.
PLA with additives — CF, Wood, Stone, Silk, Rainbow
Carbon-fiber PLA and Wood and Stone composites contain mineral or wood particles that conduct heat somewhat worse than pure PLA — so a safe range is 80–100%, tested downward if you notice weak inter-layer adhesion on thin walls. PLA Silk and Rainbow follow a different logic: they're still a PLA base, but overly aggressive cooling kills the characteristic silky sheen of the surface. For these variants, 70–90% usually gives the best compromise between gloss and detail sharpness.
Cooling PETG and technical materials
PETG is a material where most people make the same mistake: they copy PLA settings and run the fan at 100%. The result is excessive stringing and weak inter-layer adhesion, because PETG needs more time in a semi-liquid state for the layers to bond properly.
PETG and HT-PETG
For PETG and HT-PETG, moderate cooling around 30–50% works well. Too low a percentage worsens bridges and overhangs — the sagging material doesn't firm up in time and droops. Too high a percentage shows up as a matte, "frosted" surface and weakened layers that separate easily by hand. A good starting point is 40%, with further calibration depending on whether your model has more bridges (raise it) or more large, flat surfaces (lower it).
ABS and ASA
ABS and ASA are high-shrinkage materials during cooling, which is why intensive part cooling is an enemy here, not an ally. Uneven cooling between the center and the edge of the print generates stresses that pull corners off the bed — this exact mechanism is behind most cases of warping. A safe range is 0–20%, essentially fan off across the whole body, with only a brief, local airflow boost on very thin elements and bridges, where the material would otherwise simply sag.
Cooling TPU and nylon (PA)
Flexible and technical filaments need cooling more for process stability than for surface quality. In TPU, too strong an airflow aimed close to the nozzle in a Bowden setup can cool the material fast enough that it loses the flexibility it needs to pass through the PTFE tube — the result is jams and skipped extruder steps.
TPU 95A vs. TPU 98A — the cooling difference
The harder TPU 98A has a higher Shore hardness than TPU 95A and tolerates stronger cooling better — 30–50% usually causes no problems, especially on direct-drive printers. TPU 95A, being softer, needs a more careful approach: 20–40%, with a lower value on Bowden setups, where the material's path to the nozzle is longer and more prone to buckling. Nylon (PA) follows a different rule entirely: the key parameter isn't fan percentage, it's filament moisture — even perfect cooling won't fix a print made from nylon that has already absorbed moisture from the air. For PA, start at 0–30% and treat drying as the first calibration step, not the last.
How to dial in cooling step by step
Instead of guessing a percentage on your target model, print a classic cooling calibration tower — a model with growing overhangs, bridges, and thin walls, where the slicer automatically changes the fan percentage every few layers. After printing, you can visually judge at which percentage the bridges are cleanest and the overhangs smoothest, without running many separate tests.
Start from the middle value in the table above and change the percentage in steps of 10 points, watching two effects at once: surface quality (too little cooling causes blurring) and inter-layer strength (too much cooling causes brittleness, which you can check by gently trying to bend a printed sample by hand). A good setting sits exactly between these two extremes, not at either end.
Settings for popular setups
| Setup | Recommended fan % | Comment |
|---|---|---|
| Bowden (standard setup) | per the material table | Longer material path to the nozzle — don't push TPU cooling above the recommended range |
| Direct drive | per the table, +5–10 pts for TPU | A short path to the nozzle tolerates stronger airflow without jam risk |
| CoreXY in an enclosure | −10–20 pts for PLA | The raised ambient temperature inside the enclosure already assists cooling |
| AMS / CFS (multi-color system) | as for the base material | Watch the nozzle purge time on color changes — it affects layer temperature |
Most common mistakes
Too much cooling on ABS and ASA. Set the part-cooling fan to 0–20% and let stresses release evenly instead of fighting warping by raising cooling.
No cooling on PETG. A completely disabled fan on PETG ends in stringing and smeared bridges — 30–50% is a safe starting point.
Fan at 100% from the first layer. Cooling turned on too early weakens bed adhesion — start at 0% and raise it only from layer 2–3 onward.
The same percentage for every material. Copying PLA settings into a PETG or ABS profile is the most common cause of failed first prints with a new material.
Ignoring the hotend fan. Turning off the side fan to "save on noise" leads to heat creep and a clogged nozzle halfway through a long print.
Too little cooling on bridges and fine details. Even materials printed with low base cooling (ABS, ASA) need a local, temporary airflow boost on thin elements — set a higher percentage for overhangs in the slicer profile.
TPU cooling maxed out on a Bowden setup. Too strong and too close an airflow cools the material before it can pass through the tube, ending in an extruder jam — stay near the lower end of the 20–40% range.
Frequently asked questions
What fan percentage should I set for PLA?
For standard and Premium PLA, 90–100% from the second or third layer works well, with the fan off on the first layer.
Does PETG need cooling at all?
Yes, but a moderate amount — 30–50% is enough to stabilize bridges and overhangs without weakening the bonds between layers.
Why does ABS crack under strong cooling?
Uneven, rapid cooling generates internal stresses in a high-shrinkage material, which leads to cracking along the layers and corners peeling off the bed.
How do I cool TPU so it doesn't clog the nozzle?
Stay near the lower end of the recommended range (20–40% for TPU 95A) and avoid directing airflow too close to the nozzle in Bowden setups.
Do I need to turn off the fan on the first layer?
Yes, regardless of material — cooling turned on from the first layer weakens bed adhesion and increases the risk of the print detaching mid-job.
Summary
Cooling is one of those parameters that's easy to ignore until it starts ruining your prints — and at the same time one of the fastest to fix, since changing the fan percentage doesn't require re-tooling your printer or buying new hardware. Start with the values from the table, test on a model with bridges and overhangs, and fine-tune the rest in small steps.
If you're just starting out and looking for a material that forgives imperfect cooling settings, browse our range of PLA filaments — it's the most predictable starting point for learning calibration before moving on to more demanding technical materials.